number of days' supply divided by the number of elapsed days including the last prescription. v m p r = all days' supply 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. f m p r = all days' supply ≤ 365 365 \leq 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. contextual factors contextual factors along with intrapersonal circumstances such as mental states affect decisions. they can accurately predict decisions where most contextual information is identified. 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. 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. 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. 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. compliant individuals see protective measures as effective, while non-compliant people see them as problematic. course completion 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. persistence with first-line single antihypertensive drugs is extremely low during the first year of treatment. as far as lipid-lowering treatment is concerned, only one third of patients are compliant with at least 90% of their treatment. 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. 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. 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. 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. 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 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. world health organization barriers to adherence 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: barrier category poor patient-provider relationship health care team and system inadequate access to health services health care team and system high medication cost social and economic cultural beliefs social and economic level of symptom severity condition availability of effective treatments condition immediacy of beneficial effects therapy side effects therapy stigma surrounding disease patient inadequate knowledge of treatment patient improving adherence rates role of health care providers health care providers play a great role in improving adherence issues. providers can improve patient interactions through motivational interviewing and active listening. 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. technology 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. medication event monitoring systems, 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. the effectiveness of two-way email communication between health care professionals and their patients has not been adequately assessed. mobile phones as of 2019, 5.15 billion people, which equates to 67% of the global population, have a mobile device and this number is growing. 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. for example, text messaging has been used to remind patients to take medication in patients with chronic conditions such as asthma and hypertension. other examples include the use of smartphones for synchronous and asynchronous video observed therapy (vot) as a replacement for the currently resource intensive standard of directly observed therapy (dot) (recommended by the who) for tuberculosis management. other mhealth interventions for improving adherence to medication include smartphone applications, voice recognition in interactive phone calls and telepharmacy. some results show that the use of mhealth improves adherence to medication and is cost-effective, though some reviews report mixed results. studies show that using mhealth to improve adherence to medication is feasible and accepted by patients. specific mobile applications might also support adherence. mhealth interventions have also been used alongside other telehealth interventions such as wearable wireless pill sensors, smart pillboxes and smart inhalers forms of medication 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 and antipsychotic medication used to treat schizophrenia and bipolar disorder. coercion sometimes drugs are given involuntarily to ensure compliance. this can occur if an individual has been involuntarily commitment or are subjected to an outpatient commitment order, where failure to take medication will result in detention and involuntary administration of treatment.: 16 this can also occur if a patient is not deemed to have mental capacity to consent to treatment in an informed way. health and disease management 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. cancer 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. 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. the reasons for non-adherence have been given by patients as follows: the poor quality of information available to them about their treatment a lack of knowledge as to how to raise concerns whilst on medication concerns about unwanted effects issues about remembering to take medication 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: type of cancermeasure of non-adherencedefinition of non-adherencerate of non-adherence haematological malignanciesserum levels of drug metabolitesserum levels below expected threshold83% breast cancerself-reporttaking less than 90% of prescribed medicine47% leukemia or non hodgkin's lymphomalevel of drug metabolite in urinelevel lower than expected33% leukemia, hodgkin's disease, non hodgkin'sself-report and parent reportmore than one missed dose per month35% lymphoma, other malignanciesserum bioassaynot described hodgkin's disease, acute lymphocytic leukemia (all)biological markerslevel lower than expected50% alllevel of drug metabolite in urinelevel lower than expected42% alllevel of drug metabolites in bloodlevel lower than expected10% alllevel of drug metabolites in bloodlevel lower than expected2% 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 29% in the national surgical adjuvant breast and bowel project of 1998 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 90% after one year 83% after two years 74% after four years diabetes 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 which are also characterised by poor rates of adherence. diabetes non-compliance is 98% in us and the principal cause of complications related to diabetes including nerve damage and kidney failure. 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. 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. 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. 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. therefore, the risk perception and decision-making processes surrounding diabetes medication adherence are multi-faceted and complex with socioeconomic implications as well.