A scoping review of studies comparing the medication event monitoring system (MEMS) with alternative methods for measuring medication adherence

Outcome measures for adherence data from a medication event monitoring system: A literature review

WHAT IS KNOWN

Currently, medication bottles with an electronic cap are frequently used to measure medication adherence. This system is termed medication event monitoring system (MEMS). To our knowledge, the optimal method to summarize data from MEMS has not yet been determined.

OBJECTIVE

Look for best practices on how to quantify adherence data from MEMS.

METHODS

Review of PubMed, Embase and Cochrane databases for the articles on medication adherence with MEMS.

RESULTS

Of 1493 identified articles, 207 were included in this review. The MEMS cap was used for a median of 3 months (IQR: 4; range: 1 week to 24 months) in various health conditions. Many different outcome measures were used. Most studies computed an adherence score, expressed as the percentage of days on which the correct dose of medication was taken. The threshold to mark people as adherent was most frequently, arbitrarily, set at 80% (range: 67%-95%). We found no data to support a specific threshold.

DISCUSSION

Although the commonly used definition of adherence has face validity, we found no validation studies, and not all studies used the same cut-off for adherence. Ideally, a cut-off should be defined and validated in the context of the specific drug and its pharmacokinetic and dynamic characteristics, and perhaps other contextual factors, rather than generically. In addition, there was large heterogeneity in the definition of what "correct intake" of medication is.

WHAT IS NEW AND CONCLUSION

Outcome measures for MEMS data lacked standardization, and no demonstrable effort to validate any definition against a relevant clinical outcome is available. Consensus on the definition of adherence is urgently needed.

Deception in clinical trials and its impact on recruitment and adherence of study participants

Deceptive practices by participants in clinical research are prevalent. It has been shown that as high as 75% of participants withheld information to avoid exclusion from studies. Self-reported adherence has been found to be largely inaccurate. Overcoming deception is a critical issue, since the safety of study participants, the integrity of research data and research resources are at risk. In this review article, we examine deception from the perspective of investigators conducting clinical trials; we describe the types (concealment, fabrication, drug holidays and collusion), prevalence, risks, and predictors of deception, and propose an approach to reduce the impact of deception, especially on adherence, in clinical trials.

Leveraging Digital Health Technologies and Outpatient Sampling in Clinical Drug Development: A Phase I Exploratory Study

Merck & Co, Inc (Kenilworth, NJ) is investing in approaches to enrich clinical trial data and augment decision making through use of digital health technologies, outpatient sampling, and real‐time data access. As part of this strategy, a phase I study was conducted to explore a few technologies of interest. In this fixed‐sequence two‐period trial, 16 healthy subjects were administered 50‐mg once‐daily sitagliptin packaged in a bottle that electronically captured the date and time study medication was dispensed (period 1) and in a traditional pharmacy bottle (period 2). Dried blood spot samples were collected for sitagliptin concentration analysis on select study days, both in clinic and at home, with collection time recorded using an electronic diary in period 1 and by clinic staff in period 2. Study results demonstrated the feasibility and subject acceptance of collecting digital adherence data and outpatient dried blood spot samples in clinical trials and highlighted areas for future improvements.

Relationship Between Adherence Rate Threshold and Drug 'Forgiveness'

The medication adherence rate (A) is the proportion of prescribed drug doses consumed within a given time period. It is often assumed that there is an adherence rate threshold (A _th) at or above which the therapeutic effect of the medication is maintained. Drug forgiveness (F) is the number of consecutive doses that can be missed while still maintaining a therapeutic effect. At a given value for A, the therapeutic effect of the drug will be continuously maintained if there is no possibility of >F missed doses. Hence, for a once-daily drug prescribed for N days, A _th and F are related by the formula, A _th = (N - F)/N. At adherence rates below A _th the probability of maintaining the therapeutic effect is equal to the probability of there being no instances of >F consecutive missed doses. Since F is a function of the duration of the drug effect (D) and D varies depending on the specific drug's pharmacokinetic/pharmacodynamic properties, there is no universal A _th applicable to all drugs.

An innovative and comprehensive technique to evaluate different measures of medication adherence: The network meta-analysis

BACKGROUND

Poor medication adherence is associated with adverse health outcomes and higher costs of care. However, inconsistencies in the assessment of adherence are found in the literature.

OBJECTIVE

To evaluate the effect of different measures of adherence in the comparative effectiveness of complex interventions to enhance patients' adherence to prescribed medications.

METHODS

A systematic review with network meta-analysis was performed. Electronic searches for relevant pairwise meta-analysis including trials of interventions that aimed to improve medication adherence were performed in PubMed. Data extraction was conducted with eligible trials evaluating short-period adherence follow-up (until 3 months) using any measure of adherence: self-report, pill count, or MEMS (medication event monitoring system). To standardize the results obtained with these different measures, an overall composite measure and an objective composite measure were also calculated. Network meta-analyses for each measure of adherence were built. Rank order and surface under the cumulative ranking curve analyses (SUCRA) were performed.

RESULTS

Ninety-one trials were included in the network meta-analyses. The five network meta-analyses demonstrated robustness and reliability. Results obtained for all measures of adherence were similar across them and to both composite measures. For both composite measures, interventions comprising economic + technical components were the best option (90% of probability in SUCRA analysis) with statistical superiority against almost all other interventions and against standard care (odds ratio with 95% credibility interval ranging from 0.09 to 0.25 [0.02, 0.98]).

CONCLUSION

The use of network meta-analysis was reliable to compare different measures of adherence of complex interventions in short-periods follow-up. Analyses with longer follow-up periods are needed to confirm these results. Different measures of adherence produced similar results. The use of composite measures revealed reliable alternatives to establish a broader and more detailed picture of adherence.

A review of interventions ≥ 6 months by pharmacists on adherence to medicines in cardiovascular disease: Characteristics of what works and what doesn't

BACKGROUND

Nonadherence to cardiovascular medicines occurs in 60% of subjects with chronic cardiovascular disease and leads to poor outcomes. In an attempt to improve adherence and cardiovascular outcomes, interventions are often used. Interventions may involve a pharmacist, but it is not always clear whether these are effective.

OBJECTIVES

The primary objective of this review is to determine whether interventions by pharmacists, alone, discussing adherence to medicines, improve adherence to medicines for cardiovascular disease. Subsequently, the review links the characteristics of the individual studies with effectiveness or lack of effect. The second objective of this review is to consider whether any improvement in adherence with interventions by pharmacist is associated with better clinical outcomes.

METHODS

A literature search of PubMed and CINAHL for 'pharmacist', 'medicine' with 'adherence' or 'compliance' or 'persistence' was undertaken. To be included in this review, papers had to be of a pharmacist working alone and in person in an intervention of subjects with hypertension, hyperlipidemia (prior to or after a coronary artery event) or heart failure. The paper had to be published in a peer review journal, with a measure of adherence to medicines. The effectiveness of the intervention had to be evaluated after ≥6 months.

RESULTS

Only 3 out of 8 interventions by pharmacists in hypertension, and 5 out of 12 interventions in subjects with hyperlipidemia led to improved adherence to medicines. In contrast, all 6 interventions by a pharmacist in subjects with heart failure were successful in improving adherence. One characteristic of successful interventions by pharmacists to improve adherence to cardiovascular medicines is that they must be more than brief/single interventions. A second characteristic is that the intervention should not involve subjects who are already highly adherent, as it is unlikely adherence can be improved in this population. Only 2 of 3 successful interventions in hypertension were associated with small reductions in blood pressure, and only one intervention in hyperlipidemia was shown to decrease LDL-cholesterol to a small extent. In subjects with heart failure, 5 of the 6 successful studies of the successful interventions by pharmacists to increase adherence also showed improved clinical outcomes.

CONCLUSIONS

When planning an intervention to improve adherence to medicines and cardiovascular outcomes in subjects with hypertension or hyperlipidemic, by a pharmacist alone, or as part of a multi-faceted interventions, it is essential to use an intervention that has been shown to be effective, as most interventions are not effective at improving adherence or only improve adherence and clinical outcomes to a small extent. In heart failure, there is well documented evidence of interventions by pharmacists that do improve clinical outcomes, which should be adopted widely.

Quantifying bias in measuring insecticide-treated bednet use: meta-analysis of self-reported vs objectively measured adherence

Background

Insecticide-treated bednets (ITNs) are recommended for use by 3.4 billion people at risk of malaria world-wide. Policy makers rely on measurements of ITN use to optimize malaria prevention efforts. Self-reports are the most common means of assessing ITN use, but self-reports may be biased in a way that reduces their reliability as a proxy for ITN adherence. This meta-analysis compared self-reported and two methods which are more objective measures of ITN use to explore whether self-reports overestimate actual ITN adherence.

Methods

A comprehensive search of electronic databases and hand searching reference lists resulted in screening 2885 records and 202 articles were read in full. Sixteen articles with comparable data were chosen for the meta-analysis. Comparable data was defined as self-reported and objectively measured ITN use (observation of a mounted ITN or surprise visits confirming use) at the same unit of analysis, covering the same time period and same population. A random effects model was used to determine a weighted average risk difference between self-reported and objectively measured ITN use. Additional stratified analyses were conducted to explore study heterogeneity.

Results

Self-reported ITN use is 8 percentage points (95% confidence interval CI: 3 to 13) higher than objectively measured ITN use, representing a 13.6% overestimation relative to the proportion measured as adherent to ITN use by objective measures. Wide variations in the discrepancies between self-reports and objective measures were unable to be explained using stratified analyses of variables including location, year of publication, seasonality and others.

Conclusions

Self-reports overestimate ITN adherence relative to objectively measured ITN use by 13.6% and do so in an unpredictable manner that raises questions about the reliability of using self-reported ITN use alone as a surveillance tool and a guide for making policy decisions.

Creation of Data Repositories to Advance Nursing Science

Data repositories are a strategy in line with precision medicine and big data initiatives, and are an efficient way to maximize data utility and form collaborative research relationships. Nurse researchers are uniquely positioned to make a valuable contribution using this strategy. The purpose of this article is to present a review of the benefits and challenges associated with developing data repositories, and to describe the process we used to develop and maintain a data repository in HIV research. Systematic planning, data collection, synthesis, and data sharing have enabled us to conduct robust cross-sectional and longitudinal analyses with more than 200 people living with HIV. Our repository building has also led to collaboration and training, both in and out of our organization. We present a pragmatic and affordable way that nurse scientists can build and maintain a data repository, helping us continue to make to our understanding of health phenomena.

Healthcare provider-led interventions to support medication adherence following ACS: a meta-analysis

We conducted a systematic review and meta-analysis to determine the effectiveness of healthcare provider-led (HCPs) interventions to support medication adherence in patients with acute coronary syndrome (ACS). A systematic search of Cochrane Library, Medline, EMBASE, PsycINFO, Web of Science, IPA, CINAHL, ASSIA, OpenGrey, EthOS, WorldCat and PQDT was undertaken. Interventions were deemed eligible if they included adult ACS patients, were HCP-led, measured medication adherence and randomised participants to parallel groups. Intervention content was coded using the Behaviour Change Technique (BCT) Taxonomy and data were pooled for analysis using random-effects models. Our search identified 8870 records, of which 27 were eligible (23 primary studies). A meta-analysis (n=9735) revealed HCP-led interventions increased the odds of medication adherence by 54% compared to control interventions (k=23, OR 1.54, 95% CI 1.26 to 1.88, I2=57.5%). After removing outliers, there was a 41% increase in the odds of medication adherence with moderate heterogeneity (k=21, OR 1.41, 95% CI 1.21 to 1.65, I2=35.3%). Interventions that included phone contact yielded (k=12, OR 1.63, 95% CI 1.25 to 2.12, I2=32.0%) a larger effect compared to those delivered exclusively in person. A total of 32/93 BCTs were identified across interventions (mean=4.7, SD=2.2) with 'information about health consequences' (BCT 5.1) (19/23) the most common. HCP-led interventions for ACS patients appear to have a small positive impact on medication adherence. While we were able to identify BCTs among interventions, data were insufficient to determine the impact of particular BCTs on study effectiveness.

PROSPERO registration number

CRD42016037706.

What We Mean When We Talk About Adherence in Respiratory Medicine

Adequate medication adherence is key for optimal benefit of pharmacological treatments. A wealth of research has been conducted to understand and identify opportunities to intervene to improve medication adherence, but variations in adherence definitions within prior research have led to ambiguity in study findings. The lack of a standard taxonomy hinders the development of cumulative science in adherence research. This article reviews the newly established Ascertaining Barriers to Compliance (ABC) taxonomy for medication adherence with a particular focus on its relevance and applicability within the context of asthma and chronic obstructive pulmonary disease management. Building on traditional definitions and concepts within medication adherence, the ABC taxonomy considers the temporal sequence of steps a patient must undertake to be defined as "adherent to treatment": (A) initiation, (B) implementation, and (C) persistence. We explain the clinical and research relevance of differentiating between these phases, point to differences in its applicability in observational and experimental research, review strengths and limitations of available measures, and highlight recent findings on specific determinants of these behaviors. Finally, we provide recommendations for research and practice with a view to supporting and sign posting opportunities to improve future respiratory medication adherence and associated research.

Urinalysis of MMX-mesalazine as a tool to monitor 5-ASA adherence in daily IBD practice

Adherence is pivotal but challenging in ulcerative colitis (UC) treatment. Many methods to assess adherence are subjective or have limitations. (Nac-)5-aminosalicylic acid (5-ASA) urinalysis by high-performance liquid chromatography (HPLC) seems feasible and reproducible in healthy volunteers. We performed a prospective study in adult quiescent UC patients to evaluate the feasibility of spot (Nac-)5-ASA urinalysis by HPLC to assess adherence in daily inflammatory bowel disease (IBD) care. Twenty-nine patients (51.7% male, mean age 52 ± 11 years) were included (median FU 9 months) and weekly spot urine samples were collected. We found large variation in spot (Nac-)5-ASA urinary excretion that was unrelated to brand, dosing schedule or dosage of 5-ASA. In conclusion, spot (Nac-)5-ASA urinalysis is not applicable to assess 5-ASA adherence in daily IBD care.

Treatment Adherence Intervention Studies in Dermatology and Guidance on How to Support Adherence

Adequate adherence to prescribed treatment regimens can help to break the cycle of treatment failure, disease progression and subsequent treatment escalation. Unfortunately, adherence in the treatment of skin disorders such as acne, atopic dermatitis/eczema and psoriasis is often inadequate. A review of the literature identified a number of studies that tested an intervention to improve adherence in dermatology, including the following: electronic messages and/or reminders; more frequent or 'extra' clinic visits; audio-visual and internet-based interventions; and patient support programmes and/or self-management, educational training programmes. While there is no one solution or action for improving adherence, some interventions were more successful than others. We provide practical guidance on how to support adherence based on aspects of the successful interventions identified and on our collective opinion and clinical practice experience. Holding patients accountable, providing a caring and supportive environment, raising awareness of poor adherence and helping patients build a solid medication-taking habit can help to improve adherence so that patients can experience maximal treatment benefits and desired clinical outcomes.

Measuring medication adherence in asthma: Development of a novel self-report tool

OBJECTIVE

This study presents the development and validation of MIS-A (Medication Intake Survey-Asthma), a new self-report instrument measuring key adherence properties during long-term asthma treatment.

DESIGN

Within a longitudinal asthma cohort study in France and the United Kingdom, adult patients and caregivers of children responded to computer-assisted telephone interviews.

MAIN OUTCOME MEASURES

Scores for distinct adherence properties (taking adherence, correct dosing, therapeutic coverage, drug holidays, overuse) and composite measures were computed for several time intervals. We examined distributions, longitudinal variation, associations between adherence scores and concordance with adherence calculated from medication prescribing or dispensing records.

RESULTS

Nine hundred and two participants reported on adherence to 4481 medications on 4140 occasions. About 59.47 and 70.36% revealed < 100% taking adherence in the last week and month; 42.76% had a drug holiday of > 1 week in the last 4 months. Adherence varied within patients during the follow-up (intra-class correlation = . 41-.71). Correlations between adherence scores were moderate to strong (ρ = .51-.85, p ≤ .001), except medication overuse (ρ = .04-.19, p ≤.05). Four-month taking adherence was associated with dispensing adherence, but not with prescribing adherence (ρ = .33, p < .001; and .12, p = .26).

CONCLUSION

MIS-A is a promising, easy-to-use self-report tool that can capture accurately different adherence properties over a long time period.

Medication Adherence in Hematopoietic Stem Cell Transplantation: A Review of the Literature

Adherence to oral medications has been repeatedly shown to fall below the recommended 80% to 95% in pediatric and adult cancer populations. The purpose of this review is to report the state of the science about oral medication adherence during the acute phase of hematopoietic stem cell transplantation across the lifespan. An exhaustive search of the literature yielded 5 records for inclusion in the review. Two studies examined adherence in pediatrics, 2 in adults, and 1 included both pediatric and adult patients. Three studies were descriptive and 2 were interventional in design. The rate of adherence to oral medications ranged from 33% to 94.7%. Adherence decreased over time in all studies except in 1 pharmacist-led intervention study. Different methods were used to measure adherence, but most relied on self-report. Further research is needed in medication adherence in hematopoietic stem cell transplantation to better understand facilitators, barriers, and relationships to health outcomes.

Efficacy of a medication adherence enhancing intervention in transplantation: The MAESTRO-Tx trial

BACKGROUND

Well-designed randomized controlled trials (RCTs) testing efficacy of post-transplant medication adherence enhancing interventions and clinical outcomes are scarce.

METHODS

This randomized controlled trial enrolled adult heart, liver, and lung transplant recipients who were >1 year post-transplant and on tacrolimus twice daily (convenience sample) (visit 1). After a 3-month run-in period, patients were randomly assigned 1:1 to intervention group (IG) or control group (CG) (visit 2), followed by a 6-month intervention (visits 2-4) and a 6-month adherence follow-up period (visit 5). All patients used electronic monitoring for 15 months for adherence measurement, generating a daily binary adherence score per patient. Post-intervention 5-year clinical event-free survival (mortality or retransplantation) was evaluated. The IG received staged multicomponent tailored behavioral interventions (visits 2-4) building on social cognitive theory and trans-theoretical model (e.g., electronic monitoring feedback, motivational interviewing). The CG received usual care and attended visits 1-5 only. Intention-to-treat analysis used generalized estimating equation modeling and Kaplan-Meier survival analysis.

RESULTS

Of 247 patients, 205 were randomly assigned (103 IG, 102 CG). At baseline, average daily proportions of patients with correct dosing (82.6% IG, 78.4% CG) and timing adherence (75.8% IG, 72.2% CG) were comparable. The IG had a 16% higher dosing adherence post-intervention (95.1% IG, 79.1% CG; p < 0.001), resulting in odds of adherence being 5 times higher in the IG than in the CG (odds ratio 5.17, 95% confidence interval 2.86-9.38). This effect was sustained at end of follow-up (similar results for timing adherence). In the IG, 5-year clinical event-free survival was 82.5% vs 72.5% in the CG (p = 0.18).

CONCLUSION

Our intervention was efficacious in improving adherence and sustainable. Further research should investigate clinical impact, cost-effectiveness, and scalability.

Adherence to fingolimod in multiple sclerosis: an investigator-initiated, prospective, observational, single-center cohort study

OBJECTIVES

Adherence to multiple sclerosis (MS) treatment is essential to optimize the likelihood of full treatment effect. This prospective, observational, single-center cohort study investigated adherence to fingolimod over the 2 years following treatment initiation. Two facets of adherence - implementation and persistence - were examined and compared between new and experienced users of disease-modifying treatments (DMTs).

MATERIALS AND METHODS

Implementation rates were based on the proportion of days covered and calculated as percentages per half-yearly visits and over 2 years, captured through refill data, pill count, and self-report. Nonadherence was defined as taking less than 85.8% of prescribed pills. Implementation rates were classified as nonadherent (<85.8%), suboptimally adherent (≥85.8% but <96.2%), and optimally adherent (≥96.2%), including perfectly adherent (100%). Persistence, ie, time until discontinuation, was analyzed by Kaplan-Meier analysis. Reasons for discontinuation were recorded.

RESULTS

The cohort included 98 patients with relapsing MS, all of whom received a dedicated education session about their medication. Of these 80% were women, 31.6% had fingolimod as first DMT, and 68.4% had switched from other DMTs. The mean implementation rate over 2 years was 98.6% (IQR_1-3 98.51%-98.7%) and did not change significantly over time; 89% of measurements were in the optimally adherent category, 45.6% in the perfectly adherent category. There was one single occurrence of nonadherence. New users of DMTs were 1.29 times more likely to be adherent than experienced users (OR 1.29, 95% CI 1.11-1.51; P<0.001), but not more persistent. Nineteen of 98 patients discontinued fingolimod.

CONCLUSION

The very high implementation rates displayed in this sample of MS patients suggest that facilitation by health care professionals in preserving adherence behavior may be sufficient for the majority of patients. Targeted interventions should focus on patients who are nonadherent or who stop treatment without intention to reinitiate.

Effects of vilazodone on sexual functioning in healthy adults: results from a randomized, double-blind, placebo-controlled, and active-controlled study

The aim of this study is to evaluate the effects of vilazodone on sexual functioning in healthy, sexually active adults and assess the impact of medication nonadherence in this type of trial. Participants were randomized to vilazodone (20 or 40 mg/day), paroxetine (20 mg/day), or placebo for 5 weeks of double-blind treatment. The primary endpoint was change from baseline to day 35 in Change in Sexual Functioning Questionnaire (CSFQ) total score in the intent-to-treat (ITT) population. Post-hoc analyses were carried out in modified intent-to-treat (mITT) populations that excluded participants in the active-treatment groups with undetectable plasma drug concentrations at all visits (mITT-I) or at least one visit (mITT-II). In the ITT population (N=199), there were no statistically significant differences between any treatment groups for CSFQ total score change: placebo, -1.0; vilazodone 20 mg/day, -1.4; vilazodone 40 mg/day, -1.9; and paroxetine, -3.5. In mITT-I (N=197) and mITT-II (N=159), CSFQ total score change was not significantly different between vilazodone (either dose) versus placebo; the CSFQ total score decreased significantly (P<0.05) with paroxetine versus both placebo and vilazodone 20 mg/day, but not versus vilazodone 40 mg/day. Vilazodone exerted no significant effect on sexual functioning in healthy adults. Medication nonadherence can alter study results and may be an important consideration in trials with volunteer participants.

How to Screen for Non-Adherence to Antihypertensive Therapy

The quality of assessment of non-adherence to treatment in hypertensive is poor. Within this review, we discuss the different methods used to assess adherence to blood-pressure-lowering medications in hypertension patients. Subjective reports such as physicians' perceptions are inaccurate, and questionnaires completed by patients tend to overreport adherence and show a low diagnostic specificity. Indirect objective methods such as pharmacy database records can be useful, but they are limited by the robustness of the recorded data. Electronic medication monitoring devices are accurate but usually track adherence to only a single medication and can be expensive. Overall, the fundamental issue with indirect objective measures is that they do not fully confirm ingestion of antihypertensive medications. Detection of antihypertensive medications in body fluids using liquid chromatography-tandem mass spectrometry is currently, in our view, the most robust and clinically useful method to assess non-adherence to blood-pressure-lowering treatment. It is particularly helpful in patients presenting with resistant, refractory or uncontrolled hypertension despite the optimal therapy. We recommend using this diagnostic strategy to detect non-adherence alongside a no-blame approach tailoring support to address the perceptions (e.g. beliefs about the illness and treatment) and practicalities (e.g. capability and resources) influencing motivation and ability to adhere.

Adherence to antipsychotic medication among homeless adults in Vancouver, Canada: a 15-year retrospective cohort study

PURPOSE

The purpose of this study was to investigate the level of adherence to antipsychotic prescription medication in a well-defined homeless cohort over a 15-year period. We hypothesized that adherence would be well below the recommended threshold for clinical effectiveness (80 %), and that it would be strongly associated with modifiable risk factors in the social environment in which homeless people live.

METHOD

Linked baseline data (including comprehensive population-level administrative prescription records) were examined in a subpopulation of participants from two pragmatic-randomized trials that investigated Housing First for homeless and mentally ill adults. Adherence to antipsychotic medication was operationalized using the medication possession ratio. Multivariable logistic regression was used to estimate effect sizes between socio-demographic, homelessness-related and illness factors, and medication possession ratio.

RESULTS

Among the 290 participants who met inclusion criteria for the current analysis, adherence to antipsychotic prescription was significantly associated with: history of psychiatric hospitalization; receipt of primary medical services; long-acting injectable antipsychotic formulations; and duration of homelessness. Mean medication possession ratio in the pre-randomization period was 0.41. Socio-demographic characteristics previously correlated with antipsychotic non-adherence were not significantly related to medication possession ratio.

CONCLUSIONS

This is the first study to quantify the very low level of adherence to antipsychotic medication among homeless people over an extended observation period of 15 years. Each of the four factors found to be significantly associated with adherence presents opportunities for intervention. Strategies to end homelessness for this population may represent the greatest opportunity to improve adherence to antipsychotic medication.

A scoping review of studies comparing the medication event monitoring system (MEMS) with alternative methods for measuring medication adherence

Different methods are available for measuring medication adherence. In this paper, we conducted a scoping review to identify and summarize evidence of all studies comparing the Medication Event Monitoring System (MEMS) with alternative methods for measuring medication adherence. A literature search was performed using the open database www.iAdherence.org that includes all original studies reporting findings from the MEMS. Papers comparing methods for measuring adherence to solid oral formulations were included. Data was extracted using a standardized extraction table. A total of 117 articles fulfilled the inclusion criteria, including 251 comparisons. Most frequent comparisons were against self-report (n = 119) and pill count (n = 59). Similar outcome measures were used in 210 comparisons (84%), among which 78 used dichotomous variables (adherent or not) and 132 used continuous measures (adherence expressed as percentage). Furthermore, 32% of all comparisons did not estimate adherence over the same coverage period and 44% of all comparisons did not use a statistical method or used a suboptimal one. Only eighty-seven (35%) comparisons had similar coverage periods, similar outcome measures and optimal statistical methods. Compared to MEMS, median adherence was grossly overestimated by 17% using self-report, by 8% using pill count and by 6% using rating. In conclusion, among all comparisons of MEMS versus alternative methods for measuring adherence, only a few used adequate comparisons in terms of outcome measures, coverage periods and statistical method. Researchers should therefore use stronger methodological frameworks when comparing measurement methods and be aware that non-electronic measures could lead to overestimation of medication adherence.