Emerging Therapeutics, Technologies, and Drug Development Strategies to Address Patient Nonadherence and Improve Tuberculosis Treatment.

Imperfect medication adherence remains the biggest predictor of treatment failure for patients with tuberculosis. Missed doses during treatment lead to relapse, tuberculosis resistance, and further spread of disease. Understanding individual patient phenotypes, population pharmacokinetics, resistance development, drug distribution to tuberculosis lesions, and pharmacodynamics at the site of infection is necessary to fully measure the impact of adherence on patient outcomes. To decrease the impact of expected variabilityin drug intake on tuberculosis outcomes, an improvement in patient adherence and new forgiving regimens that protect against missed doses are needed. In this review, we summarize emerging technologies to improve medication adherence in clinical practice and provide suggestions on how digital adherence technologies can be incorporated in clinical trials and practice and the drug development pipeline that will lead to more forgiving regimens and benefit patients suffering from tuberculosis.

The impacts of undetected nonadherence in phase II, III and post-marketing clinical trials: An overview.

AIMS: This research aims to provide an overview of the consequences of undiagnosed nonadherence (noninitiation, suboptimal implementation, nonpersistence) in randomized clinical trials (RCTs). METHODS: This research was conducted by combining a literature review and qualitative semistructured interviews with key opinion leaders. Based on this groundwork, the consequences of undiagnosed nonadherence in RCTs were summarized and reported in a figure. This study focused on phases II, III and post-marketing in ambulatory settings across a variety of therapeutic areas and indications. RESULTS: Various consequences of nonadherence in RCTs were investigated. In phase II, drug efficacy may be underestimated, variability in the outcomes may be high and a distorted picture of side effects could be reported, resulting in an uncertain impression of the investigational product's profile and complicating decision-making. The sponsor may need to increase the sample size of the upcoming phase III study to improve its power, representing additional costs, or even terminate the study. In phase III, similar phenomena may be observed, making demonstration of efficacy to the regulatory bodies more difficult. Lastly, after commercialization, a distortion in pharmacometrics may occur: the drug may underperform, prescriptions may be refilled less often than expected or extra expenses may be incurred by the payers. This can result in post-marketing dose reduction, new competitors coming into the market and, eventually, product withdrawal. CONCLUSIONS: This research highlighted the many potential adverse consequences of undiagnosed nonadherence in RCTs, including additional costs. Collecting accurate data appeared to be crucial for decision-making throughout the drug development process.

Methodological considerations on estimating medication adherence from self-report, electronic monitoring and electronic healthcare databases using the TEOS framework.

AIMS: Measuring adherence to medication is complex due to the diversity of contexts in which medications are prescribed, dispensed and used. The Timelines-Events-Objectives-Sources (TEOS) framework outlined a process to operationalize adherence. We aimed to develop practical recommendations for quantification of medication adherence using self-report (SR), electronic monitoring (EM) and electronic healthcare databases (EHD) consistent with the TEOS framework for adherence operationalization. METHODS: An adherence methodology working group of the International Society for Medication Adherence (ESPACOMP) analysed implications of the process of medication adherence for all data sources and discussed considerations specific to SR, EM and EHD regarding the information available on the prescribing, dispensing, recommended and actual use timelines, the four events relevant for distinguishing the adherence phases, the study objectives commonly addressed with each type of data, and the potential sources of measurement error and quality criteria applicable. RESULTS: Four key implications for medication adherence measurement are common to all data sources: adherence is a comparison between two series of events (recommended and actual use); it refers to one or more specific medication(s); it applies to regular repeated events coinciding with known recommended dosing; and it requires separate measurement of the three adherence phases for a complete picture of patients' adherence. We propose recommendations deriving from these statements, and aspects to be considered in study design when measuring adherence with SR, EM and EHD using the TEOS framework. CONCLUSION: The quality of medication adherence estimates is the result of several design choices that may optimize the data available.

A framework for understanding sources of bias in medication adherence research.

The sources of bias in medication adherence research have not been comprehensively explored. We aimed to identify biases expected to affect adherence research and to develop a framework for mapping these onto the phases of adherence (initiation, implementation and discontinuation). A literature search was conducted, key papers were reviewed and a Catalogue of Bias was consulted. The specific biases related to adherence measurement and metrics were mapped onto the phases of adherence using a tabular matrix. Twenty-three biases were identified, of which 11 were specifically relevant to adherence measures and metrics. The mapping framework showed differences in the numbers and types of biases associated with each measure and metric while highlighting those common to many adherence study designs (e.g., unacceptability bias and apprehension bias). The framework will inform the design of adherence studies and the development of risk of bias tools for adherence research.

Evaluating Objective Metrics of habit strength for taking medications.

Habit strength for taking medication is associated with medication adherence. However, habit strength is typically measured via self-reports, which have limitations. Objective sensors may provide advantages to self-reports. To evaluate whether habit-strength metrics derived from objective sensor data (MEMS® Caps; AARDEX Group) are associated with self-reported habit strength and adherence (objective and self-reported) and whether objective and self-reported habit strength are independently associated with adherence. Patients (N = 79) on oral medications for type 2 diabetes completed self-reports of habit strength and medication adherence and used MEMS® Caps to take their prescribed medication for one month. MEMS® Caps data were used to create five objective metrics of habit strength (e.g., individual-level variance in pill timing) and quantify medication adherence (% days correct dosing). Consistency in behavior from week to week (versus across each day) had the greatest association with self-reported habit strength (r(78) = 0.29, p = 0.01), self-reported adherence (r(78) = 0.32, p = 0.005), and objective adherence (r(78) = 0.61, p < 0.001). Objective and self-reported habit strength were independently associated with adherence. Weekly pill-timing consistency may be more useful than daily pill-timing consistency for predicting adherence and understanding patients' medication-taking habits. Self-reports and objective metrics of habit strength may be measuring different constructs, warranting further research.

TEOS: A framework for constructing operational definitions of medication adherence based on Timelines-Events-Objectives-Sources.

AIMS: Managing adherence to medications is a priority for health systems worldwide. Adherence research is accumulating, yet the quality of the evidence is reduced by various methodological limitations. In particular, the heterogeneity and low accuracy of adherence measures have been highlighted in many literature reviews. Recent consensus-based guidelines advise on best practices in defining adherence (ABC) and reporting of empirical studies (EMERGE). While these guidelines highlight the importance of operational definitions in adherence measurement, such definitions are rarely included in study reports. To support researchers in their measurement decisions, we developed a structured approach to formulate operational definitions of adherence. METHODS: A group of adherence and research methodology experts used theoretical, methodological and practical considerations to examine the process of applying adherence definitions to various research settings, questions and data sources. Consensus was reached through iterative review of discussion summaries and framework versions. RESULTS: We introduce TEOS, a four-component framework to guide the operationalization of adherence concepts: (1) describe treatment as four simultaneous interdependent timelines (recommended and actual use, conditional on prescribing and dispensing); (2) locate four key events along these timelines to delimit the three ABC phases (first and last recommended use, first and last actual use); (3) revisit study objectives and design to fine-tune research questions and assess measurement validity and reliability needs, and (4) select data sources (e.g., electronic monitoring, self-report, electronic healthcare databases) that best address measurement needs. CONCLUSION: Using the TEOS framework when designing research and reporting explicitly on these components can improve measurement quality.

Measuring and reporting treatment adherence: What can we learn by comparing two respiratory conditions?

Medication non-adherence, defined as any deviation from the regimen recommended by their healthcare provider, can increase morbidity, mortality and side effects, while reducing effectiveness. Through studying two respiratory conditions, asthma and tuberculosis (TB), we thoroughly review the current understanding of the measurement and reporting of medication adherence. In this paper, we identify major methodological issues in the standard ways that adherence has been conceptualised, defined and studied in asthma and TB. Between and within the two diseases there are substantial variations in adherence reporting, linked to differences in dosing intervals and treatment duration. Critically, the communicable nature of TB has resulted in dose-by-dose monitoring becoming a recommended treatment standard. Through the lens of these similarities and contrasts, we highlight contemporary shortcomings in the generalised conceptualisation of medication adherence. Furthermore, we outline elements in which knowledge could be directly transferred from one condition to the other, such as the application of large-scale cost-effective monitoring methods in TB to resource-poor settings in asthma. To develop a more robust evidence-based approach, we recommend the use of standard taxonomies detailed in the ABC taxonomy when measuring and discussing adherence. Regimen and intervention development and use should be based on sufficient evidence of the commonality and type of adherence behaviours displayed by patients with the relevant condition. A systematic approach to the measurement and reporting of adherence could improve the value and generalisability of research across all health conditions.

How the EMERGE guideline on medication adherence can improve the quality of clinical trials.

Medication adherence in drug trials is suboptimal, affecting the quality of these studies and adding significant costs. Nonadherence in this setting can lead to null findings, unduly large sample sizes and the need for dose modification after a drug has been approved. Despite these drawbacks, adherence behaviours are not consistently measured, analysed or reported appropriately in trial settings. The ESPACOMP Medication Adherence Reporting Guideline (EMERGE) offers a solution by facilitating a sound protocol design that takes this crucial factor into account. This article summarises key evidence on traditional and newer measurements of adherence, discusses implementation in clinical trial settings and makes recommendations about the analysis and interpretation of adherence data. Given the potential benefits of this approach, the authors call on regulators and the pharmaceutical industry to endorse the EMERGE guideline.

The ABC taxonomy for medication adherence translated into French and German.

AIMS: We translated the ABC adherence taxonomy (i.e. 7 terms and their corresponding definitions) published by Vrijens et al. (2012) into French and German without changing the original meaning with the aim to promote a standardised taxonomy for medication adherence to French- and German-speaking researchers and clinicians. METHODS: A Delphi survey was performed. To generate round 1, we identified French and German synonyms for the 7 adherence terms through a literature search in PubMed. Investigators translated the original English definitions into French and German. Panellists were members of ESPACOMP-the International Society for Patient Medication Adherence; experts suggested by ESPACOMP members and first authors of medication adherence publications in French and German. Google forms were used to create online questionnaires. Delphi rounds were performed until consensus was reached. The consensus was defined according to the acceptance rate as moderate consensus (50-75%), consensus (>75-95%), and strong consensus (>95%). RESULTS: The literature search resulted in 4-6 (French) and 4-7 (German) items per English term. Delphi rounds were launched between November 2016 and April 2018. Three rounds sufficed to reach consensus on all terms and definitions from 26 French-speaking and 25 German-speaking panellists. Preferred terms for medication adherence are adhésion médicamenteuse (82%) in French and Medikamentenadhärenz (88%) in German. CONCLUSION: The use of a common terminology for medication adherence with translations in French and German will contribute to standardise the vocabulary, to harmonise research projects and ultimately ease comparison of study results among researchers and clinicians.

The Need to Develop Standard Measures of Patient Adherence for Big Data: Viewpoint.

Despite half a century of dedicated studies, medication adherence remains far from perfect, with many patients not taking their medications as prescribed. The magnitude of this problem is rising, jeopardizing the effectiveness of evidence-based therapies. An important reason for this is the unprecedented demographic change at the beginning of the 21st century. Aging leads to multimorbidity and complex therapeutic regimens that create a fertile ground for nonadherence. As this scenario is a global problem, it needs a worldwide answer. Could this answer be provided, given the new opportunities created by the digitization of health care? Daily, health-related information is being collected in electronic health records, pharmacy dispensing databases, health insurance systems, and national health system records. These big data repositories offer a unique chance to study adherence both retrospectively and prospectively at the population level, as well as its related factors. In order to make full use of this opportunity, there is a need to develop standardized measures of adherence, which can be applied globally to big data and will inform scientific research, clinical practice, and public health. These standardized measures may also enable a better understanding of the relationship between adherence and clinical outcomes, and allow for fair benchmarking of the effectiveness and cost-effectiveness of adherence-targeting interventions. Unfortunately, despite this obvious need, such standards are still lacking. Therefore, the aim of this paper is to call for a consensus on global standards for measuring adherence with big data. More specifically, sound standards of formatting and analyzing big data are needed in order to assess, uniformly present, and compare patterns of medication adherence across studies. Wide use of these standards may improve adherence and make health care systems more effective and sustainable.

Standardized classification and framework for reporting, interpreting, and analysing medication non-adherence in cardiovascular clinical trials: a consensus report from the Non-adherence Academic Research Consortium (NARC).

Non-adherence has been well recognized for years to be a common issue that significantly impacts clinical outcomes and health care costs. Medication adherence is remarkably low even in the controlled environment of clinical trials where it has potentially complex major implications. Collection of non-adherence data diverge markedly among cardiovascular randomized trials and, even where collected, is rarely incorporated in the statistical analysis to test the consistency of the primary endpoint(s). The imprecision introduced by the inconsistent assessment of non-adherence in clinical trials might confound the estimate of the calculated efficacy of the study drug. Hence, clinical trials may not accurately answer the scientific question posed by regulators, who seek an accurate estimate of the true efficacy and safety of treatment, or the question posed by payers, who want a reliable estimate of the effectiveness of treatment in the marketplace after approval. The Non-adherence Academic Research Consortium is a collaboration among leading academic research organizations, representatives from the U.S. Food and Drug Administration and physician-scientists from the USA and Europe. One in-person meeting was held in Madrid, Spain, culminating in a document describing consensus recommendations for reporting, collecting, and analysing adherence endpoints across clinical trials. The adoption of these recommendations will afford robustness and consistency in the comparative safety and effectiveness evaluation of investigational drugs from early development to post-marketing approval studies. These principles may be useful for regulatory assessment, as well as for monitoring local and regional outcomes to guide quality improvement initiatives.

ESPACOMP Medication Adherence Reporting Guideline (EMERGE).

Research on assessing or managing medication adherence applies approaches from observational, interventional, and implementation science that spans many disciplines and demands coherent conceptualization, valid methods, appropriate analyses, and complete and accurate reporting. To ensure such reporting, the European Society for Patient Adherence, COMpliance, and Persistence (ESPACOMP) Medication Adherence Reporting Guideline (EMERGE) recommends standard reporting approaches based on an accepted taxonomy. This guideline is derived from a literature review, a reactive Delphi study with 26 medication adherence experts from many countries and disciplines, and feedback from ESPACOMP members. It is designed to supplement existing guidelines for health research reporting and is structured around 4 minimum reporting criteria and 17 items reflecting best reporting practice. By enhancing and harmonizing research reporting, EMERGE aims to advance research and, ultimately, patient outcomes.

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.

Effect of long-term adherence to clopidogrel on the VASP-PRI after elective coronary stent implantation: a randomized controlled study.

AIMS: The biological response to clopidogrel is highly variable and a poor responsiveness is associated with major adverse cardiac events. Adherence to therapy is a major cause of poor responsiveness but its impact on long-term platelet inhibition is unknown. The objective of the present study was to evaluate the effect of different programmes monitoring adherence to clopidogrel on platelet reactivity. METHODS: The study took the form of a monocentric, parallel group, randomized controlled trial. Adults treated with clopidogrel 75 mg after elective coronary stenting were randomized into one of three groups: (i) a standard of care group; (ii) a standard of care + adherence electronic monitoring group, in which drug intake was recorded but kept blinded until the study end; or (iii) an integrated care group, with regular feedback on recorded adherence. Clopidogrel response was assessed with the vasodilator-stimulated phosphoprotein-platelet reactivity index (VASP-PRI) at randomization, 3 months and 6 months. RESULTS: A total of 123 adults were enrolled and randomized. Baseline VASP-PRI was highly variable, with a mean of 48 ± 18.8%. No difference between groups in VASP-PRI was found at 6 months (P = 0.761), despite better adherence to clopidogrel in the integrated care group. However, adherence (P = 0.035) and baseline VASP-PRI (P = 0.015) were associated with VASP-PRI at 3 months and 6 months. The association between adherence and VASP-PRI was lost in patients with baseline VASP-PRI > 50%. Diabetes, CYP2C19*2 carrier status and body mass index were significant predictors of VASP-PRI. CONCLUSIONS: The platelet response to clopidogrel during chronic therapy remained highly variable, despite high adherence. Different adherence monitoring programmes did not affect VASP-PRI at 6 months. Poor adherence is associated with lower VASP-PRI only in initial good responders to clopidogrel.

Adherence to medications: insights arising from studies on the unreliable link between prescribed and actual drug dosing histories.

Satisfactory adherence to aptly prescribed medications is essential for good outcomes of patient care and reliable evaluation of competing modes of drug treatment. The measure of satisfactory adherence is a dosing history that includes timely initiation of dosing plus punctual and persistent execution of the dosing regimen throughout the specified duration of treatment. Standardized terminology for initiation, execution, and persistence of drug dosing is essential for clarity of communication and scientific progress. Electronic methods for compiling drug dosing histories are now the recognized standard for quantifying adherence, the parameters of which support model-based, continuous projections of drug actions and concentrations in plasma that are confirmable by intermittent, direct measurements at single time points. The frequency of inadequate adherence is usually underestimated by pre-electronic methods and thus is clinically unrecognized as a frequent cause of failed treatment or underestimated effectiveness. Intermittent lapses in dosing are potential sources of toxicity through hazardous rebound effects or recurrent first-dose effects.

Predictors of self-reported adherence to antihypertensive medicines: a multinational, cross-sectional survey.

BACKGROUND: Nonadherence to antihypertensive medicines limits their effectiveness, increases the risk of adverse health outcome, and is associated with significant health care costs. The multiple causes of nonadherence differ both within and between patients and are influenced by patients' care settings. OBJECTIVES: The objective of this article was to identify determinants of patient nonadherence to antihypertensive medicines, drawing from psychosocial and economic models of behavior. METHODS: Outpatients with hypertension from Austria, Belgium, England, Germany, Greece, Hungary, The Netherlands, Poland, and Wales were recruited to a cross-sectional online survey. Nonadherence to medicines was assessed using the Morisky Medication Adherence Scale (primary outcome) and the Medication Adherence Rating Scale. Associations with adherence and nonadherence were tested for demographic, clinical, and psychosocial factors. RESULTS: A total of 2595 patients completed the questionnaire. The percentage of patients classed as nonadherent ranged from 24% in The Netherlands to 70% in Hungary. Low age, low self-efficacy, and respondents' perceptions of their illness and cost-related barriers were associated with nonadherence measured on the Morisky Medication Adherence Scale across several countries. In multilevel, multivariate analysis, low self-efficacy (odds ratio = 0.73; 95% confidence interval 0.70-0.77) and a high number of perceived barriers to taking medicines (odds ratio = 1.70; 95% confidence interval 1.38-2.09) were the main significant determinants of nonadherence. Country differences explained 11% of the variance in nonadherence. CONCLUSIONS: Among the variables measured, patients' adherence to antihypertensive medicines is influenced primarily by their self-efficacy, illness beliefs, and perceived barriers. These should be targets for interventions for improving adherence, as should an appreciation of differences among the countries in which they are being delivered.

Non-vitamin K antagonist oral anticoagulants: considerations on once- vs. twice-daily regimens and their potential impact on medication adherence.

Suboptimal medication adherence is a widespread problem in ambulatory care of chronic diseases, with deviations in either direction from the prescribed dosing regimen. For the non-vitamin K antagonist oral anticoagulants (NOACs), such deviations occur and can lead to bleeding or clotting, as suboptimal adherence involves temporary periods of either overdosing or underdosing. In this expert review, we discuss: (a) the proper definition of adherence in terms of its three elements: initiation, implementation, and discontinuation; (b) how adherence is reliably and accurately measured and (c) successfully enhanced, to achieve and maintain safe and effective levels of NOAC-based anticoagulation. We also discuss the comparative effects of prescribing the same total daily dose, given either once-daily or as half-strength twice-daily doses. Because NOACs have plasma half-lives of ∼12 h, the twice-daily dosing regimen is less prone than the once-daily dosing regimen to hazardously high peaks or hazardously low troughs in anticoagulant concentrations and associated actions. As in other fields of oral drug treatment, the continuity of drug action is greater with twice-daily than with once-daily dosing, despite the fact that a few more doses are skipped with twice-daily than with once-daily dosing. This paradox is explained by the disproportionately greater impact on drug action of skipping a once-daily than a twice-daily dose. Integration of these principles into real-world medication management is the next step in the improvement of oral anticoagulation.

Measurement of adherence to BCR-ABL inhibitor therapy in chronic myeloid leukemia: current situation and future challenges.

BCR-ABL inhibitors for treating chronic myeloid leukemia in chronic phase have transformed a previously incurable malignancy into a manageable condition. However, suboptimal medication adherence has been observed with these agents affecting clinical outcomes and healthcare costs. In order to raise awareness of the problem of adherence, and before developing pragmatic strategies to enhance medication adherence, a deep understanding of the best approaches for measuring adherence in chronic myeloid leukemia patients and identifying non-adherence is required. A systematic literature review on the prevalence, measurement methods, consequences and risk factors for non-adherence to BCR-ABL inhibitors and adherence-enhancing interventions was performed and critically appraised. Of the 19 included articles, 9 were retrospective. Average adherence varied from 19% to almost 100% of the proportion of prescribed drug taken, but it was measured through various different methods and within different study groups. Suboptimal adherence was associated with a negative impact on both clinical and economic outcomes. There is a lack of supportive evidence demonstrating a difference in adherence across BCR-ABL inhibitors and even contradictory results between the 2(nd) generation inhibitors. Drug-related adverse events and forgetfulness were common reasons for intentional and unintentional non-adherence, respectively, but further research is required to identify additional reasons behind non-adherence or patients at risk of non-adherence. Non-adherence in chronic myeloid leukemia patients treated with BCR-ABL inhibitors is common and associated with critical outcomes. However, this review highlights important existing gaps, reveals inconsistent definitions, and a lack of standardized methods for measuring adherence in chronic myeloid leukemia. All require further investigation.

Projected inhibition of platelet aggregation with ticagrelor twice daily vs. clopidogrel once daily based on patient adherence data (the TWICE project).

AIM: Twice daily dosing is often perceived as inferior to once daily dosing due to a higher likelihood of missing a dose. However, more important is the extent to which drug action is maintained when doses are delayed or missed. We compared the estimated inhibition of platelet aggregation (eIPA) for ticagrelor twice daily and clopidogrel once daily, based on their pharmacokinetic/ pharmacodynamic relationships and patient dosing history data. METHODS: Drug dosing histories of 5014 patients prescribed cardiovascular medications (primarily antihypertensive medicines) were extracted from an electronically compiled dosing history database. eIPA levels were simulated for 677 twice daily and 677 once daily dosing histories over a 30 day period, based on published onset/offset models for ticagrelor and clopidogrel IPA characteristics. RESULTS: While many patients treated twice daily missed at least one dose in 30 days, only 25.7% missed two consecutive doses. By comparison, 46.8% of patients treated once daily missed at least one dose. Simulations based on patient adherence over time showed that the average mean eIPA for ticagrelor twice daily remained significantly higher than for clopidogrel once daily (81.1% vs. 55.0%, P < 0.001). Ticagrelor twice daily patients had an eIPA below 10% for 0.20% of the 30 day period compared with 2.05% for clopidogrel once daily (P = 0.0001). CONCLUSIONS: The projected level of platelet inhibition remained higher for ticagrelor twice daily than clopidogrel once daily, mainly due to the higher eIPA level achieved with ticagrelor and the relatively low likelihood of missing two consecutive twice daily doses. This modelling and simulation study suggests a therapeutic benefit of ticagrelor over clopidogrel when taking into account the most common dosing omissions.