Adherence (medicine)

In medicine, compliance (synonymous with adherence, capacitance) describes the degree to which a patient correctly follows medical advice. Most commonly, it refers to medication or drug compliance, but it can also apply to medical device use, self care, self-directed exercises, or therapy sessions. Both patient and health-care provider affect compliance, and a positive physician-patient relationship is the most important factor in improving compliance.{{cite book |author=World Health Organization |title=Adherence to long-term therapies: evidence for action |publisher=World Health Organisation |location=Geneva |year=2003 |isbn=978-92-4-154599-0 |url=https://www.who.int/chp/knowledge/publications/adherence_full_report.pdf}}

As of 2003, US health care professionals more commonly used the term "adherence" to a regimen rather than "compliance", because it has been thought to reflect better the diverse reasons for patients not following treatment directions in part or in full.{{cite journal | vauthors = Ngoh LN | title = Health literacy: a barrier to pharmacist-patient communication and medication adherence | journal = Journal of the American Pharmacists Association | volume = 49 | issue = 5 | pages = e132-46; quiz e147-9 | year = 2009 | pmid = 19748861 | doi = 10.1331/JAPhA.2009.07075 | s2cid = 22522485 }}{{cite journal | vauthors = Tilson HH | title = Adherence or compliance? Changes in terminology | journal = The Annals of Pharmacotherapy | volume = 38 | issue = 1 | pages = 161–162 | date = January 2004 | pmid = 14742813 | doi = 10.1345/aph.1D207 | s2cid = 44291441 }} Additionally, the term adherence includes the ability of the patient to take medications as prescribed by their physician with regards to the correct drug, dose, route, timing, and frequency.{{cite report | vauthors = Viswanathan M, Golin CE, Jones CD, Ashok M, Blalock S, Wines RC, Coker-Schwimmer EJ, Grodensky CA, Rosen DL, Yuen A, Sista P, Lohr KN | url = http://www.effectivehealthcare.ahrq.gov/reports/final.cfm | title = Medication Adherence Interventions: Comparative Effectiveness. Closing the Quality Gap: Revisiting the State of the Science. | archive-url = https://web.archive.org/web/20170106114324/http://www.effectivehealthcare.ahrq.gov/reports/final.cfm. | archive-date=2017-01-06 | work = Evidence Report No. 208 | publisher = RTI International–University of North Carolina Evidence-based Practice Center under Contract No. 290-2007-10056-I. AHRQ Publication No. 12-E010-EF. Rockville, MD: Agency for Healthcare Research and Quality. | date = September 2012 }} It has been noted that compliance may only refer to passively following orders.{{cite journal | vauthors = Nizar R, Elham AJ, Hasan AA | year = 2013| title = The golden factor in adherence to inhaled corticosteroid in asthma patients | journal = Egyptian Journal of Chest Diseases and Tuberculosis | volume = 62 | issue = 3| pages = 371–376 | doi = 10.1016/j.ejcdt.2013.07.010| doi-access = free }} The term adherence is often used to imply a collaborative approach to decision-making and treatment between a patient and clinician.

The term concordance has been used in the United Kingdom to involve a patient in the treatment process to improve compliance, and refers to a 2003 NHS initiative. In this context, the patient is informed about their condition and treatment options, involved in the decision as to which course of action to take, and partially responsible for monitoring and reporting back to the team.{{cite journal | vauthors = Marinker M, Shaw J | title = Not to be taken as directed | journal = BMJ | volume = 326 | issue = 7385 | pages = 348–349 | date = February 2003 | pmid = 12586645 | pmc = 1125224 | doi = 10.1136/bmj.326.7385.348 }} Informed intentional non-adherence is when the patient, after understanding the risks and benefits, chooses not to take the treatment.{{cite web |title=Therapeutics Initiative {{!}} [132] Rethinking Medication Adherence |url=https://www.ti.ubc.ca/2021/09/08/132-rethinking-medication-adherence/ |access-date=5 April 2022 |language=en-CA}}

As of 2005, the preferred terminology remained a matter of debate.{{cite journal | vauthors = Osterberg L, Blaschke T | title = Adherence to medication | journal = The New England Journal of Medicine | volume = 353 | issue = 5 | pages = 487–497 | date = August 2005 | pmid = 16079372 | doi = 10.1056/NEJMra050100 | s2cid = 36218142 }} As of 2007, concordance has been used to refer specifically to patient adherence to a treatment regimen which the physician sets up collaboratively with the patient, to differentiate it from adherence to a physician-only prescribed treatment regimen.{{cite journal | vauthors = Bell JS, Airaksinen MS, Lyles A, Chen TF, Aslani P | title = Concordance is not synonymous with compliance or adherence | journal = British Journal of Clinical Pharmacology | volume = 64 | issue = 5 | pages = 710–1; author reply 711–3 | date = November 2007 | pmid = 17875196 | pmc = 2203263 | doi = 10.1111/j.1365-2125.2007.02971_1.x }}{{cite journal | vauthors = Aronson JK | title = Compliance, concordance, adherence | journal = British Journal of Clinical Pharmacology | volume = 63 | issue = 4 | pages = 383–384 | date = April 2007 | pmid = 17378797 | pmc = 2203247 | doi = 10.1111/j.1365-2125.2007.02893.x }}{{cite web |author=US NIH Office of Behavior and Social Sciences Research |url=http://obssr.od.nih.gov/pdf/Workshop_final_report.pdf |title=Framework for adherence research and translation: a blueprint for the next ten years |year=2008 |access-date=2010-05-12 |archive-url=https://web.archive.org/web/20100528015152/http://obssr.od.nih.gov/pdf/Workshop_final_report.pdf |archive-date=2010-05-28 |url-status=dead }} Despite the ongoing debate, adherence has been the preferred term for the World Health Organization, The American Pharmacists Association,{{cite web |work=APA Highlights Newsletter |title=Enhancing Patient Adherence: Proceedings of the Pinnacle Roundtable Discussion |date=October 2004 |volume=7 |issue=4 |url=http://www.pharmacist.com/AM/Template.cfm?Section=Home2&TEMPLATE=/CM/ContentDisplay.cfm&CONTENTID=11174 |access-date=2018-10-02 |archive-url=https://web.archive.org/web/20110615092834/http://www.pharmacist.com/AM/Template.cfm?Section=Home2&TEMPLATE=%2FCM%2FContentDisplay.cfm&CONTENTID=11174 |archive-date=2011-06-15 |url-status=dead }} and the U.S. National Institutes of Health Adherence Research Network.{{cite web |author=Office of Behavior and Social Sciences Research |publisher=U.S. National Institutes of Health |title=Adherence Research Network |url=http://obssr.od.nih.gov/scientific_areas/health_behaviour/adherence/adherenceresearchnetwork.aspx |access-date=12 May 2010 |archive-url=https://web.archive.org/web/20100502064804/http://obssr.od.nih.gov/scientific_areas/health_behaviour/adherence/adherenceresearchnetwork.aspx |archive-date=2010-05-02 |url-status=dead }} The Medical Subject Headings of the United States National Library of Medicine defines various terms with the words [https://www.ncbi.nlm.nih.gov/mesh/?term=adherence adherence] and [https://www.ncbi.nlm.nih.gov/mesh/?term=compliance compliance]. [https://www.ncbi.nlm.nih.gov/mesh/68010349 Patient Compliance] and [https://www.ncbi.nlm.nih.gov/mesh/68055118 Medication Adherence] are distinguished under the MeSH tree of [https://www.ncbi.nlm.nih.gov/mesh/2023381 Treatment Adherence and Compliance].

In 2003 WHO estimated that half of those for whom long term treatment regimens are prescribed do not follow them as directed.

In general, adherence is higher in diseases where people see a greater health threat, such as HIV/AIDS and cancer, and it is lower for chronic conditions such as hypertension, asthma or diabetes.{{Cite journal |last1=McQuaid |first1=Elizabeth L. |last2=Landier |first2=Wendy |date=February 2018 |title=Cultural Issues in Medication Adherence: Disparities and Directions |journal=Journal of General Internal Medicine |volume=33 |issue=2 |pages=200–206 |doi=10.1007/s11606-017-4199-3 |issn=1525-1497 |pmc=5789102 |pmid=29204971}}

Factors can be categorized on 3 levels: individual, cultural and healthcare system level.

Depressive symptoms and perceived discrimination have been correlated with poor adherence.

Negative side effects of a medicine can influence adherence.{{cite journal | vauthors = Jin J, Sklar GE, Min Sen Oh V, Chuen Li S | title = Factors affecting therapeutic compliance: A review from the patient's perspective | journal = Therapeutics and Clinical Risk Management | volume = 4 | issue = 1 | pages = 269–286 | date = February 2008 | pmid = 18728716 | pmc = 2503662 | doi = 10.2147/tcrm.s1458 | doi-access = free }}{{Rp|280}}

Medication adherence rates are typically lower with lower socioeconomic status, increased stress related to difficult life circumstances.

Poverty is associated with Low levels of literacy and numeracy. Adults in more deprived areas, such as the North East of England, performed at a lower level than those in less deprived areas such as the South East. Local authority tenants and those in poor health were particularly likely to lack basic skills.

In 1999 one fifth of UK adults, nearly seven million people, had problems with basic skills, especially functional literacy and functional numeracy, described as: "The ability to read, write and speak in English, and to use mathematics at a level necessary to function at work and in society in general." This made it impossible for them to effectively take medication, read labels, follow drug regimes, and find out more.[https://web.archive.org/web/20120506180044/http://educationengland.org.uk/documents/pdfs/1999-moser-summary.pdf Moser Report Summary] educationengland.org, 14 pages (1999)retrieved 28. 12. 2017

In 2003, 20% of adults in the UK had a long-standing illness or disability and a national study for the UK Department of Health, found more than one-third of people with poor or very poor health had literary skills of Entry Level 3 or below.{{cite web|vauthors=Williams J, Clemens S, Oleinikova K, Tarvin K |year=2003 |title=The skills for life survey. A national needs and impact survey of literacy, numeracy and ICT skills |location=London |publisher=Department for Education and Skills |url=https://www.education.gov.uk/publications/RSG/BasicSkills/Page3/RB490}}

A study of the relationship of literacy to asthma knowledge revealed that only 31% of asthma patients with a reading level of a ten-year-old knew they needed to see the doctors, even when they were not having an asthma attack, compared to 90% with a high school graduate reading level.{{cite journal | vauthors = Williams MV, Baker DW, Honig EG, Lee TM, Nowlan A | title = Inadequate literacy is a barrier to asthma knowledge and self-care | journal = Chest | volume = 114 | issue = 4 | pages = 1008–1015 | date = October 1998 | pmid = 9792569 | doi = 10.1378/chest.114.4.1008 }}

In 2013 the US National Community Pharmacists Association sampled for one month 1,020 Americans above age 40 for with an ongoing prescription to take medication for a chronic condition and gave a grade C+ on adherence.[http://www.pharmacytimes.com/association-news/new-report-card-on-medication-use-gives-americans-a-c New Report Card on Medication Use Gives Americans a C+] {{Webarchive|url=https://web.archive.org/web/20171228232027/http://www.pharmacytimes.com/association-news/new-report-card-on-medication-use-gives-americans-a-c |date=2017-12-28 }} Pharmacy Times. JUNE 25, 2013{{better source needed|date=December 2017}} In 2009, this contributed to an estimated cost of $290 billion annually.Thinking Outside the Pillbox: A System-wide Approach to Improving Patient Adherence for Chronic Disease." NEHI. 2009 In 2012, increase in patient medication cost share was found to be associated with low adherence to medication.{{cite journal | vauthors = Eaddy MT, Cook CL, O'Day K, Burch SP, Cantrell CR | title = How patient cost-sharing trends affect adherence and outcomes: a literature review | journal = P & T | volume = 37 | issue = 1 | pages = 45–55 | date = January 2012 | pmid = 22346336 | pmc = 3278192 }}

The United States is among the countries with the highest prices of prescription drugs mainly attributed to the government's lack of negotiating lower prices with monopolies in the pharmaceutical industry especially with brand name drugs.{{cite journal | vauthors = Kesselheim AS, Avorn J, Sarpatwari A | title = The High Cost of Prescription Drugs in the United States: Origins and Prospects for Reform | journal = JAMA | volume = 316 | issue = 8 | pages = 858–871 | year = 2016 | pmid = 27552619 | doi = 10.1001/jama.2016.11237 }} In order to manage medication costs, many US patients on long term therapies fail to fill their prescription, skip or reduce doses. According to a Kaiser Family Foundation survey in 2015, about three quarters (73%) of the public think drug prices are unreasonable and blame pharmaceutical companies for setting prices so high.{{cite web | title = Kaiser Family Foundation: Poll Finds Nearly Three Quarters of Americans Say Prescription Drug Costs Are Unreasonable, and Most Blame Drug Makers Rather Than Insurers for the Problem | date = 16 June 2015 | url = https://www.kff.org/health-costs/press-release/poll-finds-nearly-three-quarters-of-americans-say-prescription-drug-costs-are-unreasonable-and-most-blame-drug-makers-rather-than-insurers-for-the-problem/ | work = Kaiser Family Foundation }} In the same report, half of the public reported that they are taking prescription drugs and a "quarter (25%) of those currently taking prescription medicine report they or a family member have not filled a prescription in the past 12 months due to cost, and 18 percent report cutting pills in half or skipping doses". In a 2009 comparison to Canada, only 8% of adults reported to have skipped their doses or not filling their prescriptions due to the cost of their prescribed medications.{{cite journal | vauthors = Kennedy J, Morgan S | title = Cost-related prescription nonadherence in the United States and Canada: a system-level comparison using the 2007 International Health Policy Survey in Seven Countries | journal = Clinical Therapeutics | volume = 31 | issue = 1 | pages = 213–219 | date = January 2009 | pmid = 19243719 | doi = 10.1016/j.clinthera.2009.01.006 }}

Cost and poor understanding of the directions for the treatment, referred to as 'health literacy' have been known to be major barriers to treatment adherence.{{cite web|title=Enhancing Patient Adherence: Proceedings of the Pinnacle Roundtable Discussion|work=APA Highlights Newsletter|date= October 2004|url=http://www.pharmacist.com/AM/Template.cfm?Section=Home2&TEMPLATE=/CM/ContentDisplay.cfm&CONTENTID=11174 |access-date=2018-10-02|archive-url=https://web.archive.org/web/20110615092834/http://www.pharmacist.com/AM/Template.cfm?Section=Home2&TEMPLATE=%2FCM%2FContentDisplay.cfm&CONTENTID=11174 |archive-date=2011-06-15|url-status=dead}}{{cite journal | vauthors = Elliott RA, Marriott JL | title = Standardised assessment of patients' capacity to manage medications: a systematic review of published instruments | journal = BMC Geriatrics | volume = 9 | pages = 27 | date = July 2009 | pmid = 19594913 | pmc = 2719637 | doi = 10.1186/1471-2318-9-27 | doi-access = free }} Misinformation from the internet and social media can also lead to a delay or lack of compliance in following medical advice.{{Cite journal |last=Borges do Nascimento |first=Israel Júnior |last2=Pizarro |first2=Ana Beatriz |last3=Almeida |first3=Jussara M. |last4=Azzopardi-Muscat |first4=Natasha |last5=Gonçalves |first5=Marcos André |last6=Björklund |first6=Maria |last7=Novillo-Ortiz |first7=David |date=2022-09-01 |title=Infodemics and health misinformation: a systematic review of reviews |url=https://pmc.ncbi.nlm.nih.gov/articles/PMC9421549/ |journal=Bulletin of the World Health Organization |volume=100 |issue=9 |pages=544–561 |doi=10.2471/BLT.21.287654 |issn=1564-0604 |pmc=9421549 |pmid=36062247 |via=World Health Organization}}

The recent National Service Framework on the care of older people highlighted the importance of taking and effectively managing medicines in the elderly. Elderly individuals may face challenges, including multiple medications with frequent dosing, and potentially decreased dexterity or cognitive functioning. Patient knowledge is also a factor.{{cite journal | vauthors = Park DC, Hertzog C, Leventhal H, Morrell RW, Leventhal E, Birchmore D, Martin M, Bennett J | display-authors = 6 | title = Medication adherence in rheumatoid arthritis patients: older is wiser | journal = Journal of the American Geriatrics Society | volume = 47 | issue = 2 | pages = 172–183 | date = February 1999 | pmid = 9988288 | doi = 10.1111/j.1532-5415.1999.tb04575.x | hdl-access = free | s2cid = 25724467 | hdl = 2027.42/111192 }}

In 1999 Cline et al. identified several gaps in knowledge about medication in elderly patients discharged from hospital.{{cite journal | vauthors = Cline CM, Björck-Linné AK, Israelsson BY, Willenheimer RB, Erhardt LR | title = Non-compliance and knowledge of prescribed medication in elderly patients with heart failure | journal = European Journal of Heart Failure | volume = 1 | issue = 2 | pages = 145–149 | date = June 1999 | pmid = 10937924 | doi = 10.1016/S1388-9842(99)00014-8 | s2cid = 32043403 | doi-access = free }} Despite receiving written and verbal information, 27% of older people discharged after heart failure were classed as non-adherent within 30 days. Half the patients surveyed could not recall the dose of the medication that they were prescribed and nearly two-thirds did not know what time of day to take them. A 2001 study by Barat et al. evaluated the medical knowledge and factors of adherence in a population of 75-year-olds living at home. They found that 40% of elderly patients do not know the purpose of their regimen and only 20% knew the consequences of non-adherence.{{cite journal | vauthors = Barat I, Andreasen F, Damsgaard EM | title = Drug therapy in the elderly: what doctors believe and patients actually do | journal = British Journal of Clinical Pharmacology | volume = 51 | issue = 6 | pages = 615–622 | date = June 2001 | pmid = 11422022 | pmc = 2014493 | doi = 10.1046/j.0306-5251.2001.01401.x }} Comprehension, polypharmacy, living arrangement, multiple doctors, and use of compliance aids was correlated with adherence.

In children with asthma, self-management compliance is critical and co-morbidities have been noted to affect outcomes; in 2013 it has been suggested that electronic monitoring may help adherence.{{cite journal | vauthors = Guglani L, Havstad SL, Ownby DR, Saltzgaber J, Johnson DA, Johnson CC, Joseph CL | title = Exploring the impact of elevated depressive symptoms on the ability of a tailored asthma intervention to improve medication adherence among urban adolescents with asthma | journal = Allergy, Asthma, and Clinical Immunology | volume = 9 | issue = 1 | pages = 45 | date = November 2013 | pmid = 24479403 | pmc = 3832221 | doi = 10.1186/1710-1492-9-45 | doi-access = free }}

People of different ethnic backgrounds have unique adherence issues through, for example, limited English language proficiency, their cultural belief system rooted in historical experience (Tuskeegee experiment), resulting in medical mistrust. There are few published studies on adherence in medicine taking in ethnic minority communities. Ethnicity and culture influence some health-determining behaviour, such as participation in health screening programmes and attendance at follow-up appointments.{{cite journal | vauthors = Courtenay WH, McCreary DR, Merighi JR | title = Gender and ethnic differences in health beliefs and behaviors | journal = Journal of Health Psychology | volume = 7 | issue = 3 | pages = 219–231 | date = May 2002 | pmid = 22114246 | doi = 10.1177/1359105302007003216 | s2cid = 41828950 }}{{cite journal | vauthors = Meyerowitz BE, Richardson J, Hudson S, Leedham B | title = Ethnicity and cancer outcomes: behavioral and psychosocial considerations | journal = Psychological Bulletin | volume = 123 | issue = 1 | pages = 47–70 | date = January 1998 | pmid = 9461853 | doi = 10.1037/0033-2909.123.1.47 }}

Ethnic groups differ in their attitudes, values, culture and beliefs about health and illness, particularly with preventive treatments and medication for asymptomatic conditions. Additionally, some cultures fatalistically attribute their good or poor health to their god(s), and attach less importance to self-care than others.{{cite journal | vauthors = Prieto LR, Miller DS, Gayowski T, Marino IR | title = Multicultural issues in organ transplantation: the influence of patients' cultural perspectives on compliance with treatment | journal = Clinical Transplantation | volume = 11 | issue = 6 | pages = 529–535 | date = December 1997 | doi = 10.1111/j.1399-0012.1997.tb01038.x | pmid = 9408680 }} Complementary and alternative medicine may be taken with or instead of teh prescribed medications especially in Mexican American and Vietnamese people.

Studies have shown that black patients and those with non-private insurance are more likely to be labeled as non-adherent.Beltrán, Sourik, Lanair A. Lett, and Peter F. Cronholm. "Nonadherence labeling in primary care: bias by race and insurance type for adults with type 2 diabetes." American journal of preventive medicine 57.5 (2019): 652-658.https://doi.org/10.1016/j.amepre.2019.06.005 An increased risk for non adherence was observed even after controlling for A1c, and socioeconomic factors.Beltrán, Sourik, et al. "Associations of race, insurance, and zip code-level income with nonadherence diagnoses in primary and specialty diabetes care." The Journal of the American Board of Family Medicine 34.5 (2021): 891-897. https://doi.org/10.3122/jabfm.2021.05.200639

Not all patients will fill the prescription at a pharmacy. In a 2010 U.S. study, 20–30% of prescriptions were never filled at the pharmacy.{{cite journal | vauthors = Fischer MA, Stedman MR, Lii J, Vogeli C, Shrank WH, Brookhart MA, Weissman JS | title = Primary medication non-adherence: analysis of 195,930 electronic prescriptions | journal = Journal of General Internal Medicine | volume = 25 | issue = 4 | pages = 284–290 | date = April 2010 | pmid = 20131023 | pmc = 2842539 | doi = 10.1007/s11606-010-1253-9 }}{{cite news |author=Norton M |publisher=Reuters Health |title=Many patients may not fill their prescriptions |year=2010 |url=https://www.reuters.com/article/idUSTRE61G3QX20100217 |access-date=May 12, 2010}} Reasons people do not fill prescriptions include the cost of the medication,{{cite news |publisher=Harris Interactive |title=Out-of-pocket costs may be a substantial barrier to prescription drug compliance |url=http://www.harrisinteractive.com/news/newsletters/healthnews/HI_HealthCareNews2001Vol1_iss32.pdf |access-date=May 12, 2010 |archive-url=https://web.archive.org/web/20100103211324/http://harrisinteractive.com/news/newsletters/healthnews/HI_HealthCareNews2001Vol1_iss32.pdf |archive-date=January 3, 2010 |url-status=dead }} A US nationwide survey of 1,010 adults in 2001 found that 22% chose not to fill prescriptions because of the price, which is similar to the 20–30% overall rate of unfilled prescriptions. Other factors are doubting the need for medication, or preference for self-care measures other than medication.{{cite journal | vauthors = Shah NR, Hirsch AG, Zacker C, Taylor S, Wood GC, Stewart WF | title = Factors associated with first-fill adherence rates for diabetic medications: a cohort study | journal = Journal of General Internal Medicine | volume = 24 | issue = 2 | pages = 233–237 | date = February 2009 | pmid = 19093157 | pmc = 2629003 | doi = 10.1007/s11606-008-0870-z }}{{cite journal | vauthors = Shah NR, Hirsch AG, Zacker C, Wood GC, Schoenthaler A, Ogedegbe G, Stewart WF | title = Predictors of first-fill adherence for patients with hypertension | journal = American Journal of Hypertension | volume = 22 | issue = 4 | pages = 392–396 | date = April 2009 | pmid = 19180061 | pmc = 2693322 | doi = 10.1038/ajh.2008.367 }} Convenience, side effects and lack of demonstrated benefit are also factors.{{citation needed|date=December 2017}}

Prescription medical claims records can be used to estimate medication adherence based on fill rate. Patients can be routinely defined as being 'Adherent Patients' if the amount of medication furnished is at least 80% based on days' supply of medication divided by the number of days patient should be consuming the medication. This percentage is called the medication possession ratio (MPR). 2013 work has suggested that a medication possession ratio of 90% or above may be a better threshold for deeming consumption as 'Adherent'.{{cite journal | vauthors = Watanabe JH, Bounthavong M, Chen T | title = Revisiting the medication possession ratio threshold for adherence in lipid management | journal = Current Medical Research and Opinion | volume = 29 | issue = 3 | pages = 175–180 | date = March 2013 | pmid = 23320610 | doi = 10.1185/03007995.2013.766164 | s2cid = 206967136 }}

Two forms of MPR can be calculated, fixed and variable.{{cite journal | vauthors = Kozma CM, Dickson M, Phillips AL, Meletiche DM | title = Medication possession ratio: implications of using fixed and variable observation periods in assessing adherence with disease-modifying drugs in patients with multiple sclerosis | journal = Patient Preference and Adherence | volume = 7 | pages = 509–516 | year = 2013 | pmid = 23807840 | pmc = 3685450 | doi = 10.2147/PPA.S40736 | doi-access = free }} Calculating either is relatively straightforward, for Variable MPR (VMPR) it is calculated as the number of days' supply divided by the number of elapsed days including the last prescription.

VMPR = \dfrac{\text{All days' supply}}{\text{Elapsed days (inclusive of last prescription)}}

For the Fixed MPR (FMPR) the calculation is similar but the denominator is the number of days in a year whilst the numerator is constrained to be the number of days' supply within the year that the patient has been prescribed.

FMPR = \dfrac{\text{All days' supply} \le 365}{365}

For medication in tablet form it is relatively straightforward to calculate the number of days' supply based on a prescription. Some medications are less straightforward though because a prescription of a given number of doses may have a variable number of days' supply because the number of doses to be taken per day varies, for example with preventative corticosteroid inhalers prescribed for asthma where the number of inhalations to be taken daily may vary between individuals based on the severity of the disease.{{citation needed|date=December 2017}}

Contextual factors along with intrapersonal circumstances such as mental states affect decisions. They can accurately predict decisions where most contextual information is identified.{{Cite journal |title=Extending the Choice Architecture Toolbox: The Choice Context Mapping |url=https://psyarxiv.com/cbrwt/ |website=PsyArXiv |access-date=2022-12-01 |doi=10.31234/osf.io/cbrwt|last1=Hajdu |first1=Nandor |last2=Szaszi |first2=Barnabas |last3=Aczel |first3=Balazs |s2cid=236803979 }} General compliance with recommendations to follow isolation is influenced beliefs such as taking health precaution to be protected against infection, perceived vulnerability, getting COVID-19 and trust in the government.{{Cite journal |last1=Clark |first1=Cory |last2=Davila |first2=Andrés |last3=Regis |first3=Maxime |last4=Kraus |first4=Sascha |date=2020-01-01 |title=Predictors of COVID-19 voluntary compliance behaviors: An international investigation |journal=Global Transitions |language=en |volume=2 |pages=76–82 |doi=10.1016/j.glt.2020.06.003 |issn=2589-7918 |pmc=7318969 |pmid=32835202|bibcode=2020GloT....2...76C }} Mobility reduction, compliance with quarantine regulations in European regions where level of trust in policymakers is high can influence whether one complies with isolation rules.{{Cite journal |last1=Bargain |first1=Olivier |last2=Aminjonov |first2=Ulugbek |date=2020-12-01 |title=Trust and compliance to public health policies in times of COVID-19 |journal=Journal of Public Economics |language=en |volume=192 |pages=104316 |doi=10.1016/j.jpubeco.2020.104316 |issn=0047-2727 |pmc=7598751 |pmid=33162621}} In addition, perceived infectiousness of COVID-19 is a strong predictor of rule compliance such that the more contagious people think COVID-19 is, the less willing social distancing measures are taken, while the sense of duty and fear of the virus contribute to staying at home.{{Cite journal |last1=Harper |first1=Craig A. |last2=Satchell |first2=Liam P. |last3=Fido |first3=Dean |last4=Latzman |first4=Robert D. |date=2021-10-01 |title=Functional Fear Predicts Public Health Compliance in the COVID-19 Pandemic |url=https://doi.org/10.1007/s11469-020-00281-5 |journal=International Journal of Mental Health and Addiction |language=en |volume=19 |issue=5 |pages=1875–1888 |doi=10.1007/s11469-020-00281-5 |issn=1557-1882 |pmc=7185265 |pmid=32346359}}{{Cite journal |last1=French Bourgeois |first1=Laura |last2=Harell |first2=Allison |last3=Stephenson |first3=Laura B. |date=June 2020 |title=To Follow or Not to Follow: Social Norms and Civic Duty during a Pandemic |journal=Canadian Journal of Political Science |language=en |volume=53 |issue=2 |pages=273–278 |doi=10.1017/S0008423920000554 |issn=0008-4239 |pmc=7330279}}{{Cite journal |last1=Hajdu |first1=Nandor |last2=Schmidt |first2=Kathleen |last3=Acs |first3=Gergely |last4=Röer |first4=Jan P. |last5=Mirisola |first5=Alberto |last6=Giammusso |first6=Isabella |last7=Arriaga |first7=Patrícia |last8=Ribeiro |first8=Rafael |last9=Dubrov |first9=Dmitrii |last10=Grigoryev |first10=Dmitry |last11=Arinze |first11=Nwadiogo C. |last12=Voracek |first12=Martin |last13=Stieger |first13=Stefan |last14=Adamkovic |first14=Matus |last15=Elsherif |first15=Mahmoud |date=2022-11-28 |title=Contextual factors predicting compliance behavior during the COVID-19 pandemic: A machine learning analysis on survey data from 16 countries |journal=PLOS ONE |language=en |volume=17 |issue=11 |pages=e0276970 |doi=10.1371/journal.pone.0276970 |pmid=36441720 |issn=1932-6203 |pmc=9704675|bibcode=2022PLoSO..1776970H |doi-access=free }} People might not leave their homes due to trusting regulations to be effective or placing it in a higher power such that individuals who trust others demonstrate more compliance than those who do not.{{Cite journal |last1=DeFranza |first1=David |last2=Lindow |first2=Mike |last3=Harrison |first3=Kevin |last4=Mishra |first4=Arul |last5=Mishra |first5=Himanshu |date=July 2021 |title=Religion and reactance to COVID-19 mitigation guidelines. |url=https://doi.org/10.1037/amp0000717 |journal=American Psychologist |language=en |volume=76 |issue=5 |pages=744–754 |doi=10.1037/amp0000717 |pmid=32772540 |issn=1935-990X}}{{Cite journal |last1=Alessandri |first1=Guido |last2=Filosa |first2=Lorenzo |last3=Tisak |first3=Marie S. |last4=Crocetti |first4=Elisabetta |last5=Crea |first5=Giuseppe |last6=Avanzi |first6=Lorenzo |date=2020 |title=Moral Disengagement and Generalized Social Trust as Mediators and Moderators of Rule-Respecting Behaviors During the COVID-19 Outbreak |journal=Frontiers in Psychology |volume=11 |page=2102 |doi=10.3389/fpsyg.2020.02102 |issn=1664-1078 |pmc=7481453 |pmid=32973632|doi-access=free }} Compliant individuals see protective measures as effective, while non-compliant people see them as problematic.{{Cite journal |last1=Kleitman |first1=Sabina |last2=Fullerton |first2=Dayna J. |last3=Zhang |first3=Lisa M. |last4=Blanchard |first4=Matthew D. |last5=Lee |first5=Jihyun |last6=Stankov |first6=Lazar |last7=Thompson |first7=Valerie |date=2021-07-29 |title=To comply or not comply? A latent profile analysis of behaviours and attitudes during the COVID-19 pandemic |journal=PLOS ONE |language=en |volume=16 |issue=7 |pages=e0255268 |doi=10.1371/journal.pone.0255268 |issn=1932-6203 |pmc=8321369 |pmid=34324567|bibcode=2021PLoSO..1655268K |doi-access=free }}

Once started, patients seldom follow treatment regimens as directed, and seldom complete the course of treatment. In respect of hypertension, 50% of patients completely drop out of care within a year of diagnosis.{{cite journal | vauthors = Mapes RE | title = Physicians' drug innovation and relinquishment | journal = Social Science & Medicine | volume = 11 | issue = 11–13 | pages = 619–624 | date = September 1977 | pmid = 607411 | doi = 10.1016/0037-7856(77)90044-0 }} Persistence with first-line single antihypertensive drugs is extremely low during the first year of treatment.{{cite journal | vauthors = Mazzaglia G, Mantovani LG, Sturkenboom MC, Filippi A, Trifirò G, Cricelli C, Brignoli O, Caputi AP | display-authors = 6 | title = Patterns of persistence with antihypertensive medications in newly diagnosed hypertensive patients in Italy: a retrospective cohort study in primary care | journal = Journal of Hypertension | volume = 23 | issue = 11 | pages = 2093–2100 | date = November 2005 | pmid = 16208153 | doi = 10.1097/01.hjh.0000186832.41125.8a | s2cid = 26366054 }} As far as lipid-lowering treatment is concerned, only one third of patients are compliant with at least 90% of their treatment.{{cite journal | vauthors = Sung JC, Nichol MB, Venturini F, Bailey KL, McCombs JS, Cody M | title = Factors affecting patient compliance with antihyperlipidemic medications in an HMO population | journal = The American Journal of Managed Care | volume = 4 | issue = 10 | pages = 1421–1430 | date = October 1998 | pmid = 10338735 }} Intensification of patient care interventions (e.g. electronic reminders, pharmacist-led interventions, healthcare professional education of patients) improves patient adherence rates to lipid-lowering medicines, as well as total cholesterol and LDL-cholesterol levels.{{cite journal | vauthors = van Driel ML, Morledge MD, Ulep R, Shaffer JP, Davies P, Deichmann R | title = Interventions to improve adherence to lipid-lowering medication | journal = The Cochrane Database of Systematic Reviews | volume = 12 | issue = 3 | pages = CD004371 | date = December 2016 | pmid = 28000212 | pmc = 4163627 | doi = 10.1002/14651858.CD004371.pub4 }}

The World Health Organization (WHO) estimated in 2003 that only 50% of people complete long-term therapy for chronic illnesses as they were prescribed, which puts patient health at risk.{{cite book |author=World Health Organization |year=2003 |title=Adherence to long-term therapies: evidence for action |location=Geneva |publisher=World Health Organisation |isbn=978-92-4-154599-0 |url=https://www.who.int/chp/knowledge/publications/adherence_full_report.pdf}} For example, in 2002 statin compliance dropped to between 25 and 40% after two years of treatment, with patients taking statins for what they perceive to be preventative reasons being unusually poor compliers.{{cite journal | vauthors = Jackevicius CA, Mamdani M, Tu JV | title = Adherence with statin therapy in elderly patients with and without acute coronary syndromes | journal = JAMA | volume = 288 | issue = 4 | pages = 462–467 | year = 2002 | pmid = 12132976 | doi = 10.1001/jama.288.4.462 | doi-access = free }}

A wide variety of packaging approaches have been proposed to help patients complete prescribed treatments. These approaches include formats that increase the ease of remembering the dosage regimen as well as different labels for increasing patient understanding of directions.{{cite journal | vauthors = Shrank W, Avorn J, Rolon C, Shekelle P | title = Effect of content and format of prescription drug labels on readability, understanding, and medication use: a systematic review | journal = The Annals of Pharmacotherapy | volume = 41 | issue = 5 | pages = 783–801 | date = May 2007 | pmid = 17426075 | doi = 10.1345/aph.1H582 | s2cid = 25171756 }}{{cite journal | vauthors = Mahtani KR, Heneghan CJ, Glasziou PP, Perera R | title = Reminder packaging for improving adherence to self-administered long-term medications | journal = The Cochrane Database of Systematic Reviews | issue = 9 | pages = CD005025 | date = September 2011 | pmid = 21901694 | doi = 10.1002/14651858.CD005025.pub3 }} For example, medications are sometimes packed with reminder systems for the day and/or time of the week to take the medicine. Some evidence shows that reminder packaging may improve clinical outcomes such as blood pressure.

A not-for-profit organisation called the Healthcare Compliance Packaging Council of Europe] (HCPC-Europe) was set up{{when|date=December 2017}} between the pharmaceutical industry, the packaging industry with representatives of European patients organisations. The mission of HCPC-Europe is to assist and to educate the healthcare sector in the improvement of patient compliance through the use of packaging solutions. A variety of packaging solutions have been developed by this collaboration.[https://web.archive.org/web/20081019100628/http://www.hcpc-europe.org/cms/front_content.php?idcat=94 Healthcare Compliance Packaging Council of Europe] www.hcpc-europe.org

The World Health Organization (WHO) groups barriers to medication adherence into five categories; health care team and system-related factors, social and economic factors, condition-related factors, therapy-related factors, and patient-related factors. Common barriers include:{{Cite web|url=http://apps.who.int/medicinedocs/en/d/Js4883e/7.2.html|archive-url=https://web.archive.org/web/20120307010053/http://apps.who.int/medicinedocs/en/d/Js4883e/7.2.html|url-status=dead|archive-date=March 7, 2012|title=Adherence to Long-Term Therapies - Evidence for Action: Section II - Improving adherence rates: guidance for countries: Chapter V - Towards the solution: 1. Five interacting dimensions affect adherence|website=apps.who.int|access-date=2018-03-23}}

Health care providers play a great role in improving adherence issues. Providers can improve patient interactions through motivational interviewing and active listening.{{cite journal | vauthors = Stefanacci RG, Guerin S | title = Why medication adherence matters to patients, payers, providers | journal = Managed Care (Langhorne, Pa.) | volume = 22 | issue = 1 | pages = 37–9 | date = January 2013 | pmid = 23373139 | doi = | url = }} Health care providers should work with patients to devise a plan that is meaningful for the patient's needs. A relationship that offers trust, cooperation, and mutual responsibility can greatly improve the connection between provider and patient for a positive impact. The wording that health care professionals take when sharing health advice may have an impact on adherence and health behaviours, however, further research is needed to understand if positive framing (e.g., the chance of surviving is improved if you go for screening) versus negative framing (e.g., the chance of dying is higher if you do not go for screening) is more effective for specific conditions.{{cite journal | vauthors = Akl EA, Oxman AD, Herrin J, Vist GE, Terrenato I, Sperati F, Costiniuk C, Blank D, Schünemann H | display-authors = 6 | title = Framing of health information messages | journal = The Cochrane Database of Systematic Reviews | issue = 12 | pages = CD006777 | date = December 2011 | pmid = 22161408 | doi = 10.1002/14651858.CD006777.pub2 }}

In 2012 it was predicted that as telemedicine technology improves, physicians will have better capabilities to remotely monitor patients in real-time and to communicate recommendations and medication adjustments using personal mobile devices, such as smartphones, rather than waiting until the next office visit.{{cite journal | vauthors = Torrieri M | title = Patient compliance: technology tools for physicians. | journal = Physicians Practice | date = 2012 | url = http://www.physicianspractice.com/technology/content/article/1462168/2099609 | archive-url = https://web.archive.org/web/20121006022320/http://www.physicianspractice.com/technology/content/article/1462168/2099609 | archive-date = 2012-10-06 }}

Medication Event Monitoring Systems (MEMS), as in the form of smart medicine bottle tops, smart pharmacy vials or smart blister packages as used in clinical trials and other applications where exact compliance data are required, work without any patient input, and record the time and date the bottle or vial was accessed, or the medication removed from a blister package. The data can be read via proprietary readers, or NFC enabled devices, such as smartphones or tablets. A 2009 study stated that such devices can help improve adherence.{{cite journal | vauthors = Santschi V, Chiolero A, Burnier M | title = Electronic monitors of drug adherence: tools to make rational therapeutic decisions | journal = Journal of Hypertension | volume = 27 | issue = 11 | pages = 2294–5; author reply 2295 | date = November 2009 | pmid = 20724871 | doi = 10.1097/hjh.0b013e328332a501 }} More recently a 2016 scoping review suggested that in comparison to MEMS, median mediction adherence was grossly overestimated by 17% using self-report, by 8% using pill count and by 6% using rating as alternative methods for measuring medication adherence.{{Cite journal |last1=El Alili |first1=Mohamed |last2=Vrijens |first2=Bernard |last3=Demonceau |first3=Jenny |last4=Evers |first4=Silvia M. |last5=Hiligsmann |first5=Mickael |date=July 2016 |title=A scoping review of studies comparing the medication event monitoring system (MEMS) with alternative methods for measuring medication adherence |journal=British Journal of Clinical Pharmacology |language=en |volume=82 |issue=1 |pages=268–279 |doi=10.1111/bcp.12942 |issn=0306-5251 |pmc=4917812 |pmid=27005306}}

The effectiveness of two-way email communication between health care professionals and their patients has not been adequately assessed.{{cite journal | vauthors = Atherton H, Sawmynaden P, Sheikh A, Majeed A, Car J | title = Email for clinical communication between patients/caregivers and healthcare professionals | journal = The Cochrane Database of Systematic Reviews | volume = 2012 | pages = CD007978 | date = November 2012 | issue = 11 | pmid = 23152249 | doi = 10.1002/14651858.CD007978.pub2 | pmc = 11627151 }}

{{as of|2019}}, 5.15 billion people, which equates to 67% of the global population, have a mobile device and this number is growing.{{Cite web|url=https://www.bankmycell.com/blog/how-many-phones-are-in-the-world|title=1 Billion More Phones Than People In The World! BankMyCell| vauthors = Turner A |date=2018-07-10|website=BankMyCell|language=en-US|access-date=2019-12-04}} Mobile phones have been used in healthcare and has fostered its own term, mHealth. They have also played a role in improving adherence to medication.{{cite journal | vauthors = Thakkar J, Kurup R, Laba TL, Santo K, Thiagalingam A, Rodgers A, Woodward M, Redfern J, Chow CK | display-authors = 6 | title = Mobile Telephone Text Messaging for Medication Adherence in Chronic Disease: A Meta-analysis | journal = JAMA Internal Medicine | volume = 176 | issue = 3 | pages = 340–349 | date = March 2016 | pmid = 26831740 | doi = 10.1001/jamainternmed.2015.7667 | doi-access = free }} For example, text messaging has been used to remind patients to take medication in patients with chronic conditions such as asthma and hypertension.{{cite journal | vauthors = Anglada-Martinez H, Riu-Viladoms G, Martin-Conde M, Rovira-Illamola M, Sotoca-Momblona JM, Codina-Jane C | title = Does mHealth increase adherence to medication? Results of a systematic review | journal = International Journal of Clinical Practice | volume = 69 | issue = 1 | pages = 9–32 | date = January 2015 | pmid = 25472682 | doi = 10.1111/ijcp.12582 | s2cid = 9259305 | doi-access = free }} Other examples include the use of smartphones for synchronous and asynchronous Video Observed Therapy (VOT) as a replacement for the currently resource intensive{{cite journal | vauthors = Raviglione MC | title = The new Stop TB Strategy and the Global Plan to Stop TB, 2006-2015 | journal = Bulletin of the World Health Organization | volume = 85 | issue = 5 | pages = 327 | date = May 2007 | pmid = 17639210 | pmc = 2636638 | doi = 10.2471/blt.06.038513 }} standard of Directly Observed Therapy (DOT) (recommended by the WHO{{Cite journal| vauthors = Bhandari R |date=2018-07-22|title=International Standards for Tuberculosis Care (ISTC) and Patients' Charter: New Advances in Tuberculosis Care|journal=Health Prospect|volume=10|pages=43–45|doi=10.3126/hprospect.v10i0.5651|issn=2091-203X|doi-access=free}}) for Tuberculosis management.{{cite journal | vauthors = Ngwatu BK, Nsengiyumva NP, Oxlade O, Mappin-Kasirer B, Nguyen NL, Jaramillo E, Falzon D, Schwartzman K | display-authors = 6 | title = The impact of digital health technologies on tuberculosis treatment: a systematic review | journal = The European Respiratory Journal | volume = 51 | issue = 1 | pages = 1701596 | date = January 2018 | pmid = 29326332 | pmc = 5764088 | doi = 10.1183/13993003.01596-2017 }} Other mHealth interventions for improving adherence to medication include smartphone applications,{{cite journal | vauthors = Subhi Y, Bube SH, Rolskov Bojsen S, Skou Thomsen AS, Konge L | title = Expert Involvement and Adherence to Medical Evidence in Medical Mobile Phone Apps: A Systematic Review | journal = JMIR mHealth and uHealth | volume = 3 | issue = 3 | pages = e79 | date = July 2015 | pmid = 26215371 | pmc = 4705370 | doi = 10.2196/mhealth.4169 | doi-access = free }} voice recognition in interactive phone calls{{cite journal | vauthors = Gandapur Y, Kianoush S, Kelli HM, Misra S, Urrea B, Blaha MJ, Graham G, Marvel FA, Martin SS | display-authors = 6 | title = The role of mHealth for improving medication adherence in patients with cardiovascular disease: a systematic review | journal = European Heart Journal - Quality of Care & Clinical Outcomes | volume = 2 | issue = 4 | pages = 237–244 | date = October 2016 | pmid = 29474713 | pmc = 5862021 | doi = 10.1093/ehjqcco/qcw018 }} and Telepharmacy.{{cite journal | vauthors = Jeminiwa R, Hohmann L, Qian J, Garza K, Hansen R, Fox BI | title = Impact of eHealth on medication adherence among patients with asthma: A systematic review and meta-analysis | journal = Respiratory Medicine | volume = 149 | pages = 59–68 | date = March 2019 | pmid = 30803887 | doi = 10.1016/j.rmed.2019.02.011 | s2cid = 73479465 | doi-access = free }} Some results show that the use of mHealth improves adherence to medication and is cost-effective, though some reviews report mixed results.{{cite journal | vauthors = Hamine S, Gerth-Guyette E, Faulx D, Green BB, Ginsburg AS | title = Impact of mHealth chronic disease management on treatment adherence and patient outcomes: a systematic review | journal = Journal of Medical Internet Research | volume = 17 | issue = 2 | pages = e52 | date = February 2015 | pmid = 25803266 | pmc = 4376208 | doi = 10.2196/jmir.3951 | doi-access = free }} Studies show that using mHealth to improve adherence to medication is feasible and accepted by patients. Specific mobile applications might also support adherence.{{Cite journal |date=2020-06-02 |title=Apps to help patients take medication on time need to be evaluated in a consistent way |url=https://evidence.nihr.ac.uk/alert/apps-to-help-patients-take-medication-on-time-need-to-be-evaluated-in-a-consistent-way/ |journal=NIHR Evidence |type=Plain English summary |language=en |publisher=National Institute for Health and Care Research |doi=10.3310/alert_40365|s2cid=240805696 }}{{cite journal | vauthors = Armitage LC, Kassavou A, Sutton S | title = Do mobile device apps designed to support medication adherence demonstrate efficacy? A systematic review of randomised controlled trials, with meta-analysis | journal = BMJ Open | volume = 10 | issue = 1 | pages = e032045 | date = January 2020 | pmid = 32005778 | pmc = 7045248 | doi = 10.1136/bmjopen-2019-032045 }} mHealth interventions have also been used alongside other telehealth interventions such as wearable wireless pill sensors,{{Cite journal| vauthors = Aldeer M, Javanmard M, Martin RP |date=June 2018|title=A Review of Medication Adherence Monitoring Technologies|journal=Applied System Innovation|language=en|volume=1|issue=2|pages=14|doi=10.3390/asi1020014|doi-access=free}} smart pillboxes and smart inhalers{{cite journal | vauthors = Chan AH, Reddel HK, Apter A, Eakin M, Riekert K, Foster JM | title = Adherence monitoring and e-health: how clinicians and researchers can use technology to promote inhaler adherence for asthma | journal = The Journal of Allergy and Clinical Immunology. In Practice | volume = 1 | issue = 5 | pages = 446–454 | date = September 2013 | pmid = 24565615 | doi = 10.1016/j.jaip.2013.06.015 }}

Depot injections need to be taken less regularly than other forms of medication and a medical professional is involved in the administration of drugs so can increase compliance. Depot's are used for oral contraceptive pill{{cite journal | vauthors = Hansen LB, Saseen JJ | title = New contraceptive options: patient adherence and satisfaction | journal = American Family Physician | volume = 69 | issue = 4 | pages = 811–2, 815–6 | date = February 2004 | pmid = 14989570 | doi = }} and antipsychotic medication used to treat schizophrenia{{cite journal | vauthors = Brissos S, Veguilla MR, Taylor D, Balanzá-Martinez V | title = The role of long-acting injectable antipsychotics in schizophrenia: a critical appraisal | journal = Therapeutic Advances in Psychopharmacology | volume = 4 | issue = 5 | pages = 198–219 | date = October 2014 | pmid = 25360245 | pmc = 4212490 | doi = 10.1177/2045125314540297 }} and bipolar disorder.{{cite journal | vauthors = Calabrese JR, Jin N, Johnson B, Such P, Baker RA, Madera J, Hertel P, Ottinger J, Amatniek J, Kawasaki H | display-authors = 6 | title = Aripiprazole once-monthly as maintenance treatment for bipolar I disorder: a 52-week, multicenter, open-label study | journal = International Journal of Bipolar Disorders | volume = 6 | issue = 1 | pages = 14 | date = June 2018 | pmid = 29886522 | pmc = 6162003 | doi = 10.1186/s40345-018-0122-z | doi-access = free }}

Sometimes drugs are given involuntarily to ensure compliance. This can occur if an individual has been involuntarily committed{{cite journal | vauthors = Smith JP, Herber OR | title = Ethical issues experienced by mental health nurses in the administration of antipsychotic depot and long-acting intramuscular injections: a qualitative study | journal = International Journal of Mental Health Nursing | volume = 24 | issue = 3 | pages = 222–230 | date = June 2015 | pmid = 25394562 | doi = 10.1111/inm.12105 }} or are subjected to an outpatient commitment order, where failure to take medication will result in detention and involuntary administration of treatment.{{Cite book|url=https://www.worldcat.org/oclc/953456448|title=Coercion in community mental health care : international perspectives|date=2016| vauthors = Molodynski A, Rugkåsa J, Burns T |isbn=978-0-19-103431-2|location=Oxford|oclc=953456448}}{{Rp|16}} This can also occur if a patient is not deemed to have mental capacity to consent to treatment in an informed way.{{cite journal | vauthors = Davidson G, Brophy L, Campbell J, Farrell SJ, Gooding P, O'Brien AM | title = An international comparison of legal frameworks for supported and substitute decision-making in mental health services | journal = International Journal of Law and Psychiatry | volume = 44 | pages = 30–40 | date = January 2016 | pmid = 26318975 | doi = 10.1016/j.ijlp.2015.08.029 | hdl = 10379/11074 | s2cid = 6564501 | url = https://pure.qub.ac.uk/en/publications/an-international-comparison-of-legal-frameworks-for-supported-and-substitute-decisionmaking-in-mental-health-services(04f5c3a2-615c-4ffd-a456-22ab5678a427).html | hdl-access = free }}

A WHO study estimates that only 50% of patients with chronic diseases in developed countries follow treatment recommendations.

Asthma non-compliance (28–70% worldwide) increases the risk of severe asthma attacks requiring preventable ER visits and hospitalisations; compliance issues with asthma can be caused by a variety of reasons including: difficult inhaler use, side effects of medications, and cost of the treatment.{{cite journal | vauthors = Bender BG, Bender SE | title = Patient-identified barriers to asthma treatment adherence: responses to interviews, focus groups, and questionnaires | journal = Immunology and Allergy Clinics of North America | volume = 25 | issue = 1 | pages = 107–130 | date = February 2005 | pmid = 15579367 | doi = 10.1016/j.iac.2004.09.005 }}

200,000 new cases of cancer are diagnosed each year in the UK. One in three adults in the UK will develop cancer that can be life-threatening, and 120,000 people will be killed by their cancer each year. This accounts for 25% of all deaths in the UK. However while 90% of cancer pain can be effectively treated, only 40% of patients adhere to their medicines due to poor understanding.{{citation needed|date=December 2012}}

Results of a recent (2016) systematic review found a large proportion of patients struggle to take their oral antineoplastic medications as prescribed. This presents opportunities and challenges for patient education, reviewing and documenting treatment plans, and patient monitoring, especially with the increase in patient cancer treatments at home.{{cite journal | vauthors = Greer JA, Amoyal N, Nisotel L, Fishbein JN, MacDonald J, Stagl J, Lennes I, Temel JS, Safren SA, Pirl WF | display-authors = 6 | title = A Systematic Review of Adherence to Oral Antineoplastic Therapies | journal = The Oncologist | volume = 21 | issue = 3 | pages = 354–376 | date = March 2016 | pmid = 26921292 | pmc = 4786357 | doi = 10.1634/theoncologist.2015-0405 }}

The reasons for non-adherence have been given by patients as follows:

• The poor quality of information available to them about their treatment{{citation needed|date=December 2012}}
• A lack of knowledge as to how to raise concerns whilst on medication{{citation needed|date=December 2012}}
• Concerns about unwanted effects{{citation needed|date=December 2012}}
• Issues about remembering to take medication{{citation needed|date=December 2012}}

Partridge et al (2002) identified evidence to show that adherence rates in cancer treatment are variable, and sometimes surprisingly poor. The following table is a summary of their findings:{{cite journal | vauthors = Partridge AH, Avorn J, Wang PS, Winer EP | title = Adherence to therapy with oral antineoplastic agents | journal = Journal of the National Cancer Institute | volume = 94 | issue = 9 | pages = 652–661 | date = May 2002 | pmid = 11983753 | doi = 10.1093/jnci/94.9.652 | doi-access = free }}

• Medication event monitoring system - a medication dispenser containing a microchip that records when the container is opened and from Partridge et al (2002)

In 1998, trials evaluating Tamoxifen as a preventative agent have shown dropout rates of around one-third:

• 36% in the Royal Marsden Tamoxifen Chemoprevention Study of 1998{{cite journal | vauthors = Powles T, Eeles R, Ashley S, Easton D, Chang J, Dowsett M, Tidy A, Viggers J, Davey J | display-authors = 6 | title = Interim analysis of the incidence of breast cancer in the Royal Marsden Hospital tamoxifen randomised chemoprevention trial | journal = Lancet | volume = 352 | issue = 9122 | pages = 98–101 | date = July 1998 | pmid = 9672274 | doi = 10.1016/S0140-6736(98)85012-5 | s2cid = 25710954 }}
• 29% in the National Surgical Adjuvant Breast and Bowel Project of 1998{{cite journal | vauthors = Fisher B, Costantino JP, Wickerham DL, Redmond CK, Kavanah M, Cronin WM, Vogel V, Robidoux A, Dimitrov N, Atkins J, Daly M, Wieand S, Tan-Chiu E, Ford L, Wolmark N | display-authors = 6 | title = Tamoxifen for prevention of breast cancer: report of the National Surgical Adjuvant Breast and Bowel Project P-1 Study | journal = Journal of the National Cancer Institute | volume = 90 | issue = 18 | pages = 1371–1388 | date = September 1998 | pmid = 9747868 | doi = 10.1093/jnci/90.18.1371 | doi-access = free }}

In March 1999, the "Adherence in the International Breast Cancer Intervention Study" evaluating the effect of a daily dose of Tamoxifen for five years in at-risk women aged 35–70 years was{{cite journal | vauthors = Cuzick J, Edwards R | title = Drop-outs in tamoxifen prevention trials | journal = Lancet | volume = 353 | issue = 9156 | pages = 930 | date = March 1999 | pmid = 10094016 | doi = 10.1016/S0140-6736(05)75043-1 | s2cid = 34484166 | doi-access = free }}

• 90% after one year
• 83% after two years
• 74% after four years

Patients with diabetes are at high risk of developing coronary heart disease and usually have related conditions that make their treatment regimens even more complex, such as hypertension, obesity and depression{{cite journal | vauthors = Lustman PJ, Griffith LS, Clouse RE | title = Depression in Adults with Diabetes | journal = Seminars in Clinical Neuropsychiatry | volume = 2 | issue = 1 | pages = 15–23 | date = January 1997 | doi = 10.1053/SCNP00200015 | doi-broken-date = 1 November 2024 | pmid = 10320439 }} which are also characterised by poor rates of adherence.{{cite journal | vauthors = Ciechanowski PS, Katon WJ, Russo JE | title = Depression and diabetes: impact of depressive symptoms on adherence, function, and costs | journal = Archives of Internal Medicine | volume = 160 | issue = 21 | pages = 3278–3285 | date = November 2000 | pmid = 11088090 | doi = 10.1001/archinte.160.21.3278 | doi-access = free }}

• Diabetes non-compliance is 98% in US{{citation needed|date=December 2017}} and the principal cause of complications related to diabetes including nerve damage and kidney failure.{{citation needed|date=December 2017}}
• Among patients with Type 2 Diabetes, adherence was found in less than one third of those prescribed sulphonylureas and/or metformin. Patients taking both drugs achieve only 13% adherence.{{cite journal | vauthors = Donnan PT, MacDonald TM, Morris AD | title = Adherence to prescribed oral hypoglycaemic medication in a population of patients with Type 2 diabetes: a retrospective cohort study | journal = Diabetic Medicine | volume = 19 | issue = 4 | pages = 279–284 | date = April 2002 | pmid = 11942998 | doi = 10.1046/j.1464-5491.2002.00689.x | s2cid = 25425866 }}

Other aspects that drive medicine adherence rates is the idea of perceived self-efficacy and risk assessment in managing diabetes symptoms and decision making surrounding rigorous medication regiments. Perceived control and self-efficacy not only significantly correlate with each other, but also with diabetes distress psychological symptoms and have been directly related to better medication adherence outcomes.{{cite journal | vauthors = Gonzalez JS, Shreck E, Psaros C, Safren SA | title = Distress and type 2 diabetes-treatment adherence: A mediating role for perceived control | journal = Health Psychology | volume = 34 | issue = 5 | pages = 505–513 | date = May 2015 | pmid = 25110840 | pmc = 4324372 | doi = 10.1037/hea0000131 }} Various external factors also impact diabetic patients' self-management behaviors including health-related knowledge/beliefs, problem-solving skills, and self-regulatory skills, which all impact perceived control over diabetic symptoms.{{cite journal | vauthors = Gonzalez JS, Tanenbaum ML, Commissariat PV | title = Psychosocial factors in medication adherence and diabetes self-management: Implications for research and practice | journal = The American Psychologist | volume = 71 | issue = 7 | pages = 539–551 | date = October 2016 | pmid = 27690483 | pmc = 5792162 | doi = 10.1037/a0040388 }}

Additionally, it is crucial to understand the decision-making processes that drive diabetics in their choices surrounding risks of not adhering to their medication. While patient decision aids (PtDAs), sets of tools used to help individuals engage with their clinicians in making decisions about their healthcare options, have been useful in decreasing decisional conflict, improving transfer of diabetes treatment knowledge, and achieving greater risk perception for disease complications, their efficacy in medication adherence has been less substantial.{{cite journal | vauthors = Karagiannis T, Andreadis P, Manolopoulos A, Malandris K, Avgerinos I, Karagianni A, Tsapas A | title = Decision aids for people with Type 2 diabetes mellitus: an effectiveness rapid review and meta-analysis | journal = Diabetic Medicine | volume = 36 | issue = 5 | pages = 557–568 | date = May 2019 | pmid = 30791131 | doi = 10.1111/dme.13939 | s2cid = 73478533 }} Therefore, the risk perception and decision-making processes surrounding diabetes medication adherence are multi-faceted and complex with socioeconomic implications as well. For example, immigrant health disparities in diabetic outcomes have been associated with a lower risk perception amongst foreign-born adults in the United States compared to their native-born counterparts, which leads to fewer protective lifestyle and treatment changes crucial for combatting diabetes.{{cite journal | vauthors = Hsueh L, Peña JM, Hirsh AT, de Groot M, Stewart JC | title = Diabetes Risk Perception Among Immigrant and Racial/Ethnic Minority Adults in the United States | journal = The Diabetes Educator | volume = 45 | issue = 6 | pages = 642–651 | date = December 2019 | pmid = 31725364 | doi = 10.1177/0145721719873640 | hdl = 1805/24928 | s2cid = 202828669 | hdl-access = free }} Additionally, variations in patients' perceptions of time (i.e. taking rigorous, costly medication in the present for abstract beneficial future outcomes can conflict with patients' preferences for immediate versus delayed gratification) may also present severe consequences for adherence as diabetes medication often requires systematic, routine administration.{{cite journal | vauthors = Brown MT, Bussell J, Dutta S, Davis K, Strong S, Mathew S | title = Medication Adherence: Truth and Consequences | language = English | journal = The American Journal of the Medical Sciences | volume = 351 | issue = 4 | pages = 387–399 | date = April 2016 | pmid = 27079345 | doi = 10.1016/j.amjms.2016.01.010 | s2cid = 2242558 | doi-access = free }}

• Hypertension non-compliance (93% in US, 70% in UK){{citation needed|date=December 2017}} is the main cause of uncontrolled hypertension-associated heart attack and stroke.
• In 1975, only about 50% took at least 80% of their prescribed anti-hypertensive medications.{{cite journal | vauthors = Sackett DL, Haynes RB, Gibson ES, Hackett BC, Taylor DW, Roberts RS, Johnson AL | title = Randomised clinical trial of strategies for improving medication compliance in primary hypertension | journal = Lancet | volume = 1 | issue = 7918 | pages = 1205–1207 | date = May 1975 | pmid = 48832 | doi = 10.1016/S0140-6736(75)92192-3 | s2cid = 30096333 }}

As a result of poor compliance,{{citation needed|date=February 2017}} 75% of patients with a diagnosis of hypertension do not achieve optimum blood-pressure control.{{citation needed|date=February 2017}}

A 2003 review found that 41–59% of patients prescribed antipsychotics took the medication prescribed to them infrequently or not at all.{{cite journal | vauthors = Dolder CR, Lacro JP, Leckband S, Jeste DV | title = Interventions to improve antipsychotic medication adherence: review of recent literature | journal = Journal of Clinical Psychopharmacology | volume = 23 | issue = 4 | pages = 389–399 | date = August 2003 | pmid = 12920416 | doi = 10.1097/01.jcp.0000085413.08426.41 | s2cid = 8303124 }} Sometimes non-adherence is due to lack of insight,{{cite journal | vauthors = Olfson M, Marcus SC, Wilk J, West JC | title = Awareness of illness and nonadherence to antipsychotic medications among persons with schizophrenia | journal = Psychiatric Services | volume = 57 | issue = 2 | pages = 205–211 | date = February 2006 | pmid = 16452697 | doi = 10.1176/appi.ps.57.2.205 }} but psychotic disorders can be episodic and antipsychotics are then use prophylactically to reduce the likelihood of relapse rather than treat symptoms and in some cases individuals will have no further episodes despite not using antipsychotics.{{cite journal | vauthors = Murray RM, Quattrone D, Natesan S, van Os J, Nordentoft M, Howes O, Di Forti M, Taylor D | display-authors = 6 | title = Should psychiatrists be more cautious about the long-term prophylactic use of antipsychotics? | journal = The British Journal of Psychiatry | volume = 209 | issue = 5 | pages = 361–365 | date = November 2016 | pmid = 27802977 | doi = 10.1192/bjp.bp.116.182683 | s2cid = 3402263 | doi-access = free }} A 2006 review investigated the effects of compliance therapy for schizophrenia: and found no clear evidence to suggest that compliance therapy was beneficial for people with schizophrenia and related syndromes.{{cite journal | vauthors = McIntosh AM, Conlon L, Lawrie SM, Stanfield AC | title = Compliance therapy for schizophrenia | journal = The Cochrane Database of Systematic Reviews | volume = 3 | issue = 3 | pages = CD003442 | date = July 2006 | pmid = 16856009 | pmc = 7017223 | doi = 10.1002/14651858.CD003442.pub2 }}

A longitudinal study has shown that adherence with treatment about 60%.{{cite journal | vauthors = Balsa A, García de Yébenes MJ, Carmona L | title = Multilevel factors predict medication adherence in rheumatoid arthritis: a 6-month cohort study | journal = Annals of the Rheumatic Diseases | volume = 81 | issue = 3 | pages = 327–334 | date = March 2022 | pmid = 34844924 | doi = 10.1136/annrheumdis-2021-221163 | s2cid = 244730262 | doi-access = free }} The predictors of adherence were found to be more of psychological, communication and logistic nature rather than sociodemographic or clinical factors. The following factors were identified as independent predictors of adherence:

• the type of treatment prescribed
• agreement on treatment
• having received information on treatment adaptation
• clinician perception of patient trust

• Drug withdrawal
• Patient participation

{{Reflist|30em}}

• [https://www.who.int/chp/knowledge/publications/adherence_full_report.pdf Adherence to long-term therapies], a report from the World Health Organization
• [https://archive.today/20140306190241/http://www.rfidjournal.com/articles/view?10124/ Technology report on NFC enabled smart medication packages]

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