Treatment Adherence and Adherence Patterns of Tofacitinib and Self-Injectable TNFi Use in People with Rheumatoid Arthritis

OBJECTIVE

To assess tofacitinib and self-injectable tumor necrosis factor inhibitor (TNFi) adherence using the Medication Event Monitoring System (MEMS) and characterize association with adherence in patients with rheumatoid arthritis (RA).

METHODS

Eligible patients were enrolled from the Forward Databank within 6 months of initiating tofacitinib or injectable TNFi or from participating clinics where these were first prescribed. MEMS caps and patient diaries were used to compile dosing over 9 months. Demographics and disease characteristics were collected every 6 months, and the Beliefs about Medicines Questionnaire only at baseline. Adherence along with its components, initiation, implementation, and persistence, were calculated.

RESULTS

Of the 112 consented to participate, 82 (73%) remained in the final analysis with recruitment from clinics 47 (57%) and Forward 35 (43%). Sixty-two (76%) initiated tofacitinib with 87% taking it quaque die and twenty (24%) TNFi. At 9 months, 77% of tofacitinib were persistent versus 70% for TNFi (P = 0.65), and implementation was similar (0.84 vs. 0.82; P = 0.57). In multivariable models, increased baseline patient global assessment was consistently associated with discontinuation (hazard ratio 1.31 [1.07-1.61]). There was increased adherence to methotrexate (MTX) when taking tofacitinib that led to higher combined adherence for tofacitinib than TNFi (0.81 vs. 0.69; P = 0.03), but no significant differences remained in multivariable models. In sensitivity analysis, consistent morning intake for tofacitinib and evening intake for MTX was associated with improved adherence.

CONCLUSION

We found no statistical differences in adherence between patients with RA initiating tofacitinib and self-injectable TNFi, although 15% to 30% were nonadherent. Concomitant MTX, patient global assessment, and a consistent time of day intake were associated with adherence.

The Importance of Assessing Drug Exposure and Medication Adherence in Evaluating Investigational Medications: Ensuring Validity and Reliability of Clinical Trial Results

The objective of this current opinion paper is to draw global attention to medication adherence, emphasizing its crucial role in drug trials. Frequently, trialists lean on traditional approaches to assess medication adherence, which, while comfortable, may only reveal what trialists desire rather than offering the essential insights needed for informed decision making in drug development. Understanding drug exposure and medication adherence is paramount when evaluating the effectiveness and safety of investigational medications. Without a comprehensive understanding of how patients adhere to their prescribed treatment regimens, the integrity and dependability of clinical trial results can be compromised. This paper emphasizes the need for measures that accurately and reliably assess medication intake behaviors, enabling the differentiation between minor dosing errors and significant deviations that may impact the drug's efficacy and safety. Accurate knowledge of drug exposure empowers researchers to make informed decisions, identify potential confounding factors, and appropriately interpret study outcomes, ultimately ensuring the validity and reliability of the research findings. By prioritizing drug exposure assessment and medication adherence measurement, clinical trials can enhance their scientific rigor, contribute to more accurate evaluations of investigational medications, and ultimately speed up the development process.

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.

Translation and cross-cultural adaptation of the ABC taxonomy for medication adherence into Portuguese - Updating patients into people

BACKGROUND

The Ascertaining Barriers to Compliance (ABC) taxonomy for describing medication adherence was created in 2012, aiming to standardize terms and definitions in research and practice. The taxonomy comprises seven terms and definitions. Originally developed in English, subsequently translated into French and German, is currently being translated to Portuguese, Spanish, Czech, Romanian and Italian, aiming to promote its global use and overcome cultural barriers.

OBJECTIVES

To cross-culturally translate the ABC taxonomy into Portuguese for Portugal and Brazil.

METHODS

A systematic literature search was conducted to identify published taxonomy terms and definitions in Portuguese, and to identify panelists in medication adherence. Initial mapping of terms and definitions retrieved was scrutinized by the research team to build an e-survey. The e-survey was piloted and then sent to panelists in both countries seeking consensus using a three-round Delphi method. Consensus was defined as ≥ 85% for round 1 and ≥ 75% for round 2. Terms with agreement <10% were dropped between rounds. In round 3, terms and definitions reaching agreement between 50 and 75% were classified as moderate consensus,>75-95% as consensus and >95% as strong consensus.

RESULTS

A total of 778 studies were identified and 84 included, enabling the extraction of 154 terms and 32 definitions. In round 1, 164 panelists participated, 115 in round 2 and 99 in the round 3. Consensus was achieved in both countries for all seven terms and definitions, although with varying intensity of agreement. The term "Management of adherence" and the definition of "Discontinuation" obtained moderate consensus in both countries.

CONCLUSIONS

A unified and unique ABC taxonomy in Portuguese was possible to develop for use in Portugal and in Brazil. Its use will harmonize and standardize the terms and definitions used in clinical practice and research.

Analysing breast cancer survivors’ acceptance profiles for using an electronic pillbox connected to a smartphone application using Seintinelles, a French community-based research tool

Introduction: Up to 50% of breast cancer (BC) survivors discontinue their adjuvant endocrine therapy (AET) before the recommended 5 years, raising the issue of medication non-adherence. eHealth technologies have the potential to support patients to enhance their medication adherence and may offer an effective way to complement the healthcare. In order for eHealth technologies to be successfully implemented into the healthcare system, end-users need to be willing and accepting to use these eHealth technologies.

Aim: This study aims to evaluate the current usability of eHealth technologiesin and to identify differences in BC SURVIVORS BC survivors accepting a medication adherence enhancing eHealth technology to support their AET to BC survivors that do not accept such a medication adherence enhancing eHealth technology.

Methods: This study was conducted in 2020 including volunteering BC survivors belonging to the Seintinelles Association. Eligible participants were women, diagnosed with BC within the last 10 years, and been exposed to, an AET. Univariable and multivariable logistic regression analyses were performed to investigate medication adherence enhancing eHealth technology acceptance profiles among BC survivors. The dependent variable was defined as acceptance of an electronic pillbox connected to a smartphone application (hereafter: medication adherence enhancing eHealth technology).

Results: Overall, 23% of the participants already use a connected device or health application on a regular basis. The mean age of the participants was 52.7 (SD 10.4) years. In total, 67% of 1268 BC survivors who participated in the survey declared that they would accept a medication adherence enhancing eHealth technology to improve their AET. BC survivors accepting a medication adherence enhancing eHealth technology for their AET, are younger (OR = 0.97, 95% CI [0.95; 0.98]), do take medication for other diseases (OR = 0.31, 95% CI [0.13; 0.68]), already use a medication adherence enhancing eHealth technology or technique (OR = 1.74, 95% CI [1.06; 2.94]) and are willing to possess or currently possess one or more connected devices or health applications (OR = 2.89, 95% CI [2.01; 4.19]).

Conclusion: Understanding acceptance profiles of BC survivors is fundamental for conceiving an effective eHealth technology enhancing AET among BC survivors. Hence, such profiling will foster the development of personalized medication adherence enhancing eHealth technology.

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

AIM

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, ED, 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.

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 variability in 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. Expected final online publication date for the Annual Review of Pharmacology and Toxicology, Volume 62 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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.

A Digital Innovation for the Personalized Management of Adherence: Analysis of Strengths, Weaknesses, Opportunities, and Threats

Introduction: Personalized medicine and management of adherence are potential solutions for the suboptimal use of medicines. Digital medication management innovations currently under development combine both aspects. This research aims to investigate facilitators for and barriers to the translation of digital innovations for personalized medicine and adherence management into clinical practice from the policymaker and regulator perspective.

Methods: A mixed-method study was used combining a scoping review to identify main interests, semi-structured interviews (n = 5) with representatives of European health policymaking and regulatory organizations, and a supplementary literature review to investigate key subthemes. The SWOT analysis was used for the qualitative analysis.

Results: The literature reviews and the qualitative interviews suggested that digital solutions can facilitate the personalized management of medications and improve quality and safety, especially as the openness for digital health solutions is increasing. Digital solutions may, on the other hand, add complexity to the treatment, which can be perceived as a potential barrier for their uptake. As more multidisciplinary and participative structures are emerging, digital solutions can promote the implementation of new services. Nevertheless, change progresses slowly in the task-oriented structures of health systems. Integration of digital solutions depends on all stakeholders' willingness and abilities to co-create this change. Patients have different capabilities to self-manage their medical conditions and use digital solutions. Personalization of digital health solutions and integration in existing service structures are crucial to ensure equality among population segments. Developments in the digital infrastructure, although they are partly slow and not well-aligned, enable the implementation of innovations in clinical practice leading to further advances in data generation and usage for future innovations.

Discussion: This study suggests that digital solutions have the potential to facilitate high-quality medication management and improve adherence to medications, enable new service structures, and are essential to drive further innovations in health care. Nevertheless, increasing the self-responsibility of patients can have undesirable effects on health outcomes, especially within vulnerable population segments. Digital health solutions can be an opportunity to optimize the use of medicines and thus their efficiency. Well-conceived development and implementation processes are needed to also realize improvements in equality and solidarity within health systems.

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.

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.

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.

Community pharmacy-based study of adherence to non-vitamin K antagonist oral anticoagulants

Objective

This study aimed to assess implementation adherence (how well the patient’s actual intake matches the prescribed dosing regimen) to non-vitamin K antagonist oral anticoagulants (NOACs) and to explore experiences with and beliefs about NOACs in a real-world sample of long-term NOAC users.

Methods

A cross-sectional observational study was conducted in home-dwelling adults who started taking a NOAC at least 1 year prior to inclusion. Pharmacy dispensing data were used to calculate the Medication Possession Ratio (MPR). Patients were recruited in 158 community pharmacies in Flanders, Belgium. They completed a questionnaire collecting basic characteristics and exploring self-reported adherence to NOACs (using the Medication Adherence Report Scale, MARS) and experiences with and beliefs about NOACs (using the Beliefs about Medicines Questionnaire, BMQ).

Results

A total of 766 patients (mean age 76.2±8.8 years, median CHA2DS2-VASc score 4 (IQR=3–4)) were included. The majority (93.5%) used NOAC for stroke prevention in atrial fibrillation. The median MPR was 95.2% (IQR=87.8–99.7) which corresponds with half of the study population not taking their NOAC on at least 17 cumulative days per year. Almost 21% of participants reported non-adherence on the MARS (score <25), with unintentional non-adherence (forgetfulness) most frequently reported (15.4%). Although two-thirds of NOAC users indicated to experience adverse drug reactions, the BMQ demonstrated a positive attitude towards NOAC therapy, where necessity beliefs outweigh the concerns.

Conclusions

Our data indicate that long-term NOAC users have high implementation adherence and a positive attitude towards NOAC therapy. However, taking into account patients’ thromboembolic risk and NOACs’ short half-lives, further optimisation of NOAC use seems warranted in this population.

Brief interventions for improving adherence in schizophrenia: A pilot study using electronic medication event monitoring

Poor medication adherence remains frequent in schizophrenia. The present study examined the efficacy of two month-long pilot interventions using the Medication Event Monitoring System (MEMS®). Thirty-three outpatients at high risk for relapse were randomized to receive a smartphone-based intervention, a nurse-based intervention, or treatment as usual. All patients then used the MEMS® to objectively measure medication adherence over six months. No differences were observed in adherence measures or relapse rates across the three groups. When using electronic medication monitoring as an objective measure of adherence, easily-implemented interventions may not significantly improve adherence in patients at high risk for relapse.

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.

Improving Study Conduct and Data Quality in Clinical Trials of Chronic Pain Treatments: IMMPACT Recommendations

The estimated probability of progressing from phase 3 analgesic clinical trials to regulatory approval is approximately 57%, suggesting that a considerable number of treatments with phase 2 trial results deemed sufficiently successful to progress to phase 3 do not yield positive phase 3 results. Deficiencies in the quality of clinical trial conduct could account for some of this failure. An Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials meeting was convened to identify potential areas for improvement in trial conduct in order to improve assay sensitivity (ie, ability of trials to detect a true treatment effect). We present recommendations based on presentations and discussions at the meeting, literature reviews, and iterative revisions of this article. The recommendations relate to the following areas: 1) study design (ie, to promote feasibility), 2) site selection and staff training, 3) participant selection and training, 4) treatment adherence, 5) data collection, and 6) data and study monitoring. Implementation of these recommendations may improve the quality of clinical trial data and thus the validity and assay sensitivity of clinical trials. Future research regarding the effects of these strategies will help identify the most efficient use of resources for conducting high quality clinical trials. PERSPECTIVE: Every effort should be made to optimize the quality of clinical trial data. This manuscript discusses considerations to improve conduct of pain clinical trials based on research in multiple medical fields and the expert consensus of pain researchers and stakeholders from academia, regulatory agencies, and industry.

Determinants, consequences and potential solutions to poor adherence to anti-osteoporosis treatment: results of an expert group meeting organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the International Osteoporosis Foundation (IOF)

Many patients at increased risk of fractures do not take their medication appropriately, resulting in a substantial decrease in the benefits of drug therapy. Improving medication adherence is urgently needed but remains laborious, given the numerous and multidimensional reasons for non-adherence, suggesting the need for measurement-guided, multifactorial and individualized solutions.

INTRODUCTION

Poor adherence to medications is a major challenge in the treatment of osteoporosis. This paper aimed to provide an overview of the consequences, determinants and potential solutions to poor adherence and persistence to osteoporosis medication.

METHODS

A working group was organized by the European Society on Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal diseases (ESCEO) to review consequences, determinants and potential solutions to adherence and to make recommendations for practice and further research. A systematic literature review and a face-to-face experts meeting were undertaken.

RESULTS

Medication non-adherence is associated with increased risk of fractures, leading to a substantial decrease in the clinical and economic benefits of drug therapy. Reasons for non-adherence are numerous and multidimensional for each patient, depending on the interplay of multiple factors, suggesting the need for multifactorial and individualized solutions. Few interventions have been shown to improve adherence or persistence to osteoporosis treatment. Promising actions include patient education with counselling, adherence monitoring with feedback and dose simplification including flexible dosing regimen. Recommendations for practice and further research were also provided. To adequately manage adherence, it is important to (1) understand the problem (initiation, implementation and/or persistence), (2) to measure adherence and (3) to identify the reason of non-adherence and fix it.

CONCLUSION

These recommendations are intended for clinicians to manage adherence of their patients and to researchers and policy makers to design, facilitate and appropriately use adherence interventions.

Real-World Adherence to Oral Methotrexate Measured Electronically in Patients With Established Rheumatoid Arthritis

Objective

To assess methotrexate (MTX) adherence using the Medication Event Monitoring System (MEMS) and characterize associations with adherence in patients with rheumatoid arthritis (RA).

Methods

Eligible patients participated in Forward, the National Databank for Rheumatic Diseases, and recently (12 months or sooner) initiated oral MTX. MEMS was used to compile MTX weekly dosing over 24 weeks. The Beliefs about Medicines Questionnaire (BMQ) was completed, and baseline demographics and disease characteristics obtained. MTX adherence (percentage of weeks dose taken correctly), implementation (percentage of weeks dose taken correctly from initiation until last dose), and persistence (duration from initiation to last dose) were calculated. Analyses measured associations between patient characteristics and adherence, modeled using logistic generalized estimating equations and censored Poisson regression, and persistence modeled using Cox regression.

Results

Overall, 60 of 119 eligible patients were included in the analysis. MTX adherence, implementation, and persistence were 75%, 80%, and 83%, respectively, at 24 weeks. Demographics and disease characteristics were generally similar between patients with 1 week or less and 2 weeks or more of missed MTX. Unemployment, less disability, higher Patient Global scores, and no prior disease‐modifying antirheumatic drug (DMARD) use were associated with correct dosing. No significant differences in adherence were observed between patients receiving concomitant MTX versus MTX monotherapy, and biologic DMARD‐experienced versus biologic DMARD‐naïve patients. Higher scores in BMQ Specific Necessity (indicating a greater belief in the necessity of the medication) was associated with a decreased likelihood of dosing at an interval shorter than prescribed (odds ratio 0.89).

Conclusion

Even in a participatory group over a short period, MTX adherence was suboptimal and associated with certain demographics, medication experience, and beliefs about medicines. This suggests a need for screening and alternative treatment opportunities in nonadherent MTX patients with RA.

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.

Evaluation of adherence patterns in schizophrenia using electronic monitoring (MEMS®): A six-month post-discharge prospective study

BACKGROUND

Medication Event Monitoring System (MEMS®) is considered the gold standard for the evaluation of medication adherence, yet few studies have applied this method, especially over long periods of time.

OBJECTIVE

To investigate medication adherence patterns in a sample of post-discharge patients with schizophrenia monitored with MEMS caps during a six-month period.

METHOD

Adherence to antipsychotics was prospectively investigated using MEMS among 68 patients with schizophrenia. Treatment initiation, implementation or whether or not the patient takes his dosing regimen as prescribed, persistence or the length of time between initiation and discontinuation, and treatment discontinuation were used to describe adherence. Persistence over time was described using Kaplan-Meier curves.

RESULTS

After discharge 16% of the patients never initiated treatment. On average 37.3% of patients adhered to treatment in the first 6months. However, a strong decrease in adherence was observed over time (p<0.0001), primarily due by treatment non-persistence. Only half of the patients were persistent at 6weeks, persistence further dropped to 19.0% after 6months. Among persistent patients, implementation was consistent over time with 87.8% of patients taking their medication as prescribed on any given day.

CONCLUSIONS

Dosing profile analysis provides further evidence for the magnitude of non-adherence with antipsychotic prescriptions among post-discharge patients with schizophrenia. Using the high precision of MEMS®, dosing profiles may provide a better understanding of non-adherence patterns and help clinicians determine optimal individualized strategies.

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.

Comparative Long-Term Effect of Three Anti-P2Y12 Drugs after Percutaneous Angioplasty: An Observational Study Based on Electronic Drug Adherence Monitoring

Aims: Dual platelet inhibition using anti-P2Y12 drugs and aspirin is the standard of care in patients after percutaneous coronary interventions (PCI). Prasugrel and ticagrelor have been shown to be more potent than clopidogrel with less high on-treatment platelet reactivity. Whether differences in long-term adherence to these drugs can partly explain different antiplatelet efficacy has not been studied so far. The objective was to compare the long-term P2Y12 receptor inhibition and drug adherence to different anti-P2Y12 drugs, and to assess the impact of adherence on the pharmacodynamic effect. Methods: Monocentric, prospective, observational study. Stable outpatients treated with clopidogrel 75 mg once daily, prasugrel 10 mg once daily or ticagrelor 90 mg twice daily after PCI with stent implantation were included. Drug adherence was recorded during 6 months using electronic monitoring. Platelet responsiveness was assessed with the vasodilator-stimulated phosphoprotein platelet reactivity index (VASP-PRI) at inclusion, 3 and 6 months. Results: 120 patients had VASP-PRI and adherence data available. At 6-months, mean VASP-PRI (±SD) was 17.7 ± 11.0% with ticagrelor, 29.2 ± 15.5% with prasugrel and 47.2 ± 17.6% with clopidogrel (ANOVA, P < 0.0001). Median [IQR] taking adherence was 96 [82-100]% with ticagrelor, 100 [97-101]% with prasugrel and 100 [99-101]% with clopidogrel (p = 0.0001). Median [IQR] correct dosing was 88 [73-95]% with ticagrelor, 97 [92.5-98]% with prasugrel and 98 [96-99]% with clopidogrel (p = 0.0001). Anti-P2Y12 drug (p ≤ 0.001) and diabetes (p = 0.014) emerged as predictors of poor antiplatelet response after adjusting for age, BMI, sex, and CYP2C19^∗2 carriers status. Conclusion: Drug adherence to anti-P2Y12 drugs assessed with electronic monitoring was very high. However, anti-P2Y12 drugs showed significant differences in antiplatelet activity, with newer anti-P2Y12 drugs ticagrelor and prasugrel exerting a stronger P2Y12 receptor inhibition. These data suggest that pharmacokinetic-pharmacodynamic differences between oral anti-P2Y12 drugs are more important than adherence in determining antiplatelet efficacy when adherence to prescription is high. The study was registered (Current Controlled Trials ISRCTN85949729).

Does co-payment for inhaler devices affect therapy adherence and disease outcomes? A historical, matched cohort study

BACKGROUND

Adherence to asthma and chronic obstructive pulmonary disease (COPD) treatment has been shown to depend on patient-level factors, such as disease severity, and medication-level factors, such as complexity. However, little is known about the impact of prescription charges - a factor at the health care system level. This study used real-life data to investigate whether co-payment affects adherence (implementation and persistence) and disease outcomes in patients with asthma or COPD.

METHODS

A matched, historical cohort study was carried out using two UK primary care databases. The exposure was co-payment for prescriptions, which is required for most patients in England but not in Scotland. Two comparison cohorts were formed: one comprising patients registered at general practices in England and the other comprising patients registered in Scotland. Patients aged 20-59 years with asthma, or 40-59 years with COPD, who were initiated on fluticasone propionate/salmeterol xinafoate, were included, matched to patients in the opposite cohort, and followed up for 1 year following fluticasone propionate/salmeterol xinafoate initiation. The primary outcome was good adherence, defined as medication possession ratio ≥80%, and was analyzed using conditional logistic regression. Secondary outcomes included exacerbation rate.

RESULTS

There were 1,640 patients in the payment cohort, ie, England (1,378 patients with asthma and 262 patients with COPD) and 619 patients in the no-payment cohort, ie, Scotland (512 patients with asthma and 107 patients with COPD). The proportion of patients with good adherence was 34.3% and 34.9% in the payment and no-payment cohorts, respectively, across both disease groups. In a multivariable model, no difference in odds of good adherence was found between the cohorts (odds ratio, 1.04; 95% confidence interval, 0.85-1.27). There was also no difference in exacerbation rate.

CONCLUSION

There was no difference in adherence between matched patients registered in England and Scotland, suggesting that prescription charges do not have an impact on adherence to treatment.

Improving antiretroviral therapy adherence in resource-limited settings at scale: a discussion of interventions and recommendations

Introduction: Successful population-level antiretroviral therapy (ART) adherence will be necessary to realize both the clinical and prevention benefits of antiretroviral scale-up and, ultimately, the end of AIDS. Although many people living with HIV are adhering well, others struggle and most are likely to experience challenges in adherence that may threaten virologic suppression at some point during lifelong therapy. Despite the importance of ART adherence, supportive interventions have generally not been implemented at scale. The objective of this review is to summarize the recommendations of clinical, research, and public health experts for scalable ART adherence interventions in resource-limited settings. Methods: In July 2015, the Bill and Melinda Gates Foundation convened a meeting to discuss the most promising ART adherence interventions for use at scale in resource-limited settings. This article summarizes that discussion with recent updates. It is not a systematic review, but rather provides practical considerations for programme implementation based on evidence from individual studies, systematic reviews, meta-analyses, and the World Health Organization Consolidated Guidelines for HIV, which include evidence from randomized controlled trials in low- and middle-income countries. Interventions are categorized broadly as education and counselling; information and communication technology-enhanced solutions; healthcare delivery restructuring; and economic incentives and social protection interventions. Each category is discussed, including descriptions of interventions, current evidence for effectiveness, and what appears promising for the near future. Approaches to intervention implementation and impact assessment are then described. Results and discussion: The evidence base is promising for currently available, effective, and scalable ART adherence interventions for resource-limited settings. Numerous interventions build on existing health care infrastructure and leverage available resources. Those most widely studied and implemented to date involve peer counselling, adherence clubs, and short message service (SMS). Many additional interventions could have an important impact on ART adherence with further development, including standardized counselling through multi-media technology, electronic dose monitoring, decentralized and differentiated models of care, and livelihood interventions. Optimal targeting and tailoring of interventions will require improved adherence measurement. Conclusions: The opportunity exists today to address and resolve many of the challenges to effective ART adherence, so that they do not limit the potential of ART to help bring about the end of AIDS.

Current Situation of Medication Adherence in Hypertension

Despite increased awareness, poor adherence to treatments for chronic diseases remains a global problem. Adherence issues are common in patients taking antihypertensive therapy and associated with increased risks of coronary and cerebrovascular events. Whilst there has been a gradual trend toward improved control of hypertension, the number of patients with blood pressure values above goal has remained constant. This has both personal and economic consequences. Medication adherence is a multifaceted issue and consists of three components: initiation, implementation, and persistence. A combination of methods is recommended to measure adherence, with electronic monitoring and drug measurement being the most accurate. Pill burden, resulting from free combinations of blood pressure lowering treatments, makes the daily routine of medication taking complex, which can be a barrier to optimal adherence. Single-pill fixed-dose combinations simplify the habit of medication taking and improve medication adherence. Re-packing of medication is also being utilized as a method of improving adherence. This paper presents the outcomes of discussions by a European group of experts on the current situation of medication adherence in hypertension.

ESPACOMP Medication Adherence Reporting Guidelines (EMERGE): a reactive-Delphi study protocol

INTRODUCTION

Medication adherence is fundamental to achieving optimal patient outcomes. Reporting research on medication adherence suffers from some issues-including conceptualisation, measurement and data analysis-that thwart its advancement. Using the ABC taxonomy for medication adherence as the conceptual basis, a steering committee of members of the European Society for Patient Adherence, COMpliance, and Persistence (ESPACOMP) launched an initiative to develop ESPACOMP Medication Adherence Reporting Guidelines (EMERGE). This paper is a protocol for a Delphi study that aims to build consensus among a group of topic experts regarding an item list that will support developing EMERGE.

METHODS AND ANALYSIS

This study uses a reactive-Delphi design where a group of topic experts will be asked to rate the relevance and clarity of an initial list of items, in addition to suggesting further items and/or modifications of the initial items. The initial item list, generated by the EMERGE steering committee through a structured process, consists of 26 items distributed in 2 sections: 4 items representing the taxonomy-based minimum reporting criteria, and 22 items organised according to the common reporting sections. A purposive sample of experts will be selected from relevant disciplines and diverse geographical locations. Consensus will be achieved through predefined decision rules to keep, delete or modify the items. An iterative process of online survey rounds will be carried out until consensus is reached.

ETHICS AND DISSEMINATION

An ethics approval was not required for the study according to the Swiss federal act on research involving human beings. The participating experts will be asked to give an informed consent. The results of this Delphi study will feed into EMERGE, which will be disseminated through peer-reviewed publications and presentations at conferences. Additionally, the steering committee will encourage their endorsement by registering the guidelines at the Enhancing the QUAlity and Transparency Of health Research (EQUATOR) network and other relevant organisations.

Coming full circle in the measurement of medication adherence: opportunities and implications for health care

There is little debate that medication nonadherence is a major public health issue and that measuring nonadherence is a crucial step toward improving it. Moreover, while measuring adherence is becoming both more feasible and more common in the era of electronic information, the reliability and usefulness of various measurements of adherence have not been well established. This paper outlines the most commonly used measures of adherence and discusses the advantages and disadvantages of each that depend on the purpose for which the measure will be used. International consensus statements on definitions and guidelines for selection and use of medication adherence measures were reviewed. The quality of recommended measures was evaluated in selected publications from 2009 to 2014. The most robust medication adherence measures are often ill suited for large-scale use. Less robust measures were found to be commonly misapplied and subsequently misinterpreted in population-level analyses. Adherence assessment and measurement were rarely integrated into standard patient care practice patterns. Successful scalable and impactful strategies to improve medication adherence will depend on understanding how to efficiently and effectively measure adherence.

Immunosuppressive therapy after solid-organ transplantation: does the INTERMED identify patients at risk of poor adherence?

Background:

Lack of adherence to medication is a trigger of graft rejection in solid-organ transplant (SOT) recipients.

Objective:

This exploratory study aimed to assess whether a biopsychosocial evaluation using the INTERMED instrument before transplantation could identify SOT recipients at risk of suboptimal post-transplantation adherence to immunosuppressant drugs. We hypothesized that complex patients (INTERMED>20) might have lower medication adherence than noncomplex patients (INTERMED≤20).

Methods:

Each patient eligible for transplantation at the University Hospital of Lausanne, Switzerland, has to undergo a pre-transplantation psychiatric evaluation. In this context the patient was asked to participate in our study. The INTERMED was completed pre-transplantation, and adherence to immunosuppressive medication was monitored post-transplantation by electronic monitors for 12 months. The main outcome measure was the implementation and persistence to two calcineurin inhibitors, cyclosporine and tacrolimus, according to the dichotomized INTERMED score (>20 or ≤20).

Results:

Among the 50 SOT recipients who completed the INTERMED, 32 entered the study. The complex (N=11) and noncomplex patients (N=21) were similar in terms of age, sex and transplanted organ. Implementation was 94.2% in noncomplex patients versus 87.8% in complex patients (non-significant p-value). Five patients were lost to follow-up: one was non-persistent, and four refused electronic monitoring. Of the four patients who refused monitoring, two were complex and withdrew early, and two were noncomplex and withdrew later in the study.

Conclusion:

Patients identified as complex pre-transplant by the INTERMED tended to deviate from their immunosuppressant regimen, but the findings were not statistically significant. Larger studies are needed to evaluate this association further, as well as the appropriateness of using a nonspecific biopsychosocial instrument such as INTERMED in highly morbid patients who have complex social and psychological characteristics.

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.

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.

Commentary on "A Framework for Quantifying the Influence of Adherence and Dose Individualization"

Drugs that provide long durations of action after a last-taken dose are said to be "forgiving," as they allow the patient a degree of latitude in the timing of sequential doses. New research, by Assawasuwannakit et al.,(1) based on exemplary methods, enriches the pharmacometric analysis of forgiveness, which for several decades had been a simply descriptive reminder that the beneficial actions of some drugs can continue for hours or days after the disappearance of detectable drug.

Adherence of patients to long-term medication: a cross-sectional study of antihypertensive regimens in Austria

OBJECTIVE

The objective of this study was to evaluate adherence and causes for non-adherence to antihypertensive therapy in Austrian patients. A special focus was placed on social parameters and behavioural theories.

METHODS

Patients were invited via advertisements in community pharmacies in Austria to complete an online survey. Inclusion criteria were an age of 18 years or older, a diagnosis of arterial hypertension and a current prescription of antihypertensive medication. Adherence was measured by the four-item Morisky scale. Non-adherence was defined by at least one point in the Morisky scale. Several demographic, social and behavioural parameters were analysed as potential co-variables associated with adherence.

RESULTS

A total of 323 patients completed the online survey, of which 109 (33.7%) met the criteria for non-adherence. In a multivariable model, self-efficacy and age were associated with adherence, whereas intention and barriers were linked to non-adherence; 56 patients (17.3%) were classified as intentionally non-adherent.

CONCLUSION

This study demonstrates that non-adherence affects an important proportion of patients in the treatment of arterial hypertension. Young age was a particularly important risk factor for non-adherence, and this patient population is, therefore, in need of special attention. Modifiable risk factors were identified that could help improving the treatment of arterial hypertension and potentially other chronic conditions.

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.

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.

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.

Successful Projection of the Time Course of Drug Concentration in Plasma During a 1-Year Period From Electronically Compiled Dosing-Time Data Used as Input to Individually Parameterized Pharmacokinetic Models

Pharmacokinetic studies rely on blood sampling at times relative to predefined dosing intervals. Intensive sampling is often done under direct observation of dose taking, which, though costly, virtually eliminates uncertainty about actual dosing times. In contrast, the sparse sampling done in population pharmacokinetic studies relies on patient-reported times of dosing, the accuracy of which the authors sought to assess by adding electronic monitoring to the usual patient reporting of dosing times. The study involved 35 antiretroviral-naive, human immunodeficency virus-infected patients and was designed to assess the safety, tolerability, pharmacokinetics, and antiviral activity of prescribed lopinavir/ritonavir (800/200 mg qd or 400/100 mg bid), stavudine, and lamivudine. The present research reports the pharmacokinetic analysis that results from taking into account the patients' actual dosing histories. Intensive sampling for plasma lopinavir concentrations was done at week 3, and 4 additional predose (trough) concentrations were measured during the next 12 months. Convergence was achieved by fitting a simple 1-compartment pharmacokinetic model, with first-order absorption and elimination, to the sparse sampling data, using electronic monitoring-reported times. In contrast, convergence was not achieved using the simple model when steady state was assumed, and the times for the last qd dose or the last 2 bid doses, as reported by the patient, were used as model input. Estimated individual pharmacokinetic parameters were then combined with electronic dosing histories to project each patient's internal drug exposure over long periods of time. This strategy may provide a basis for greatly increasing the informational yield and utility of conventional therapeutic drug monitoring.

A new taxonomy for describing and defining adherence to medications

Interest in patient adherence has increased in recent years, with a growing literature that shows the pervasiveness of poor adherence to appropriately prescribed medications. However, four decades of adherence research has not resulted in uniformity in the terminology used to describe deviations from prescribed therapies. The aim of this review was to propose a new taxonomy, in which adherence to medications is conceptualized, based on behavioural and pharmacological science, and which will support quantifiable parameters. A systematic literature review was performed using MEDLINE, EMBASE, CINAHL, the Cochrane Library and PsycINFO from database inception to 1 April 2009. The objective was to identify the different conceptual approaches to adherence research. Definitions were analyzed according to time and methodological perspectives. A taxonomic approach was subsequently derived, evaluated and discussed with international experts. More than 10 different terms describing medication-taking behaviour were identified through the literature review, often with differing meanings. The conceptual foundation for a new, transparent taxonomy relies on three elements, which make a clear distinction between processes that describe actions through established routines ('Adherence to medications', 'Management of adherence') and the discipline that studies those processes ('Adherence-related sciences'). 'Adherence to medications' is the process by which patients take their medication as prescribed, further divided into three quantifiable phases: 'Initiation', 'Implementation' and 'Discontinuation'. In response to the proliferation of ambiguous or unquantifiable terms in the literature on medication adherence, this research has resulted in a new conceptual foundation for a transparent taxonomy. The terms and definitions are focused on promoting consistency and quantification in terminology and methods to aid in the conduct, analysis and interpretation of scientific studies of medication adherence.

A new taxonomy for describing and defining adherence to medications

Interest in patient adherence has increased in recent years, with a growing literature that shows the pervasiveness of poor adherence to appropriately prescribed medications. However, four decades of adherence research has not resulted in uniformity in the terminology used to describe deviations from prescribed therapies. The aim of this review was to propose a new taxonomy, in which adherence to medications is conceptualized, based on behavioural and pharmacological science, and which will support quantifiable parameters. A systematic literature review was performed using MEDLINE, EMBASE, CINAHL, the Cochrane Library and PsycINFO from database inception to 1 April 2009. The objective was to identify the different conceptual approaches to adherence research. Definitions were analyzed according to time and methodological perspectives. A taxonomic approach was subsequently derived, evaluated and discussed with international experts. More than 10 different terms describing medication-taking behaviour were identified through the literature review, often with differing meanings. The conceptual foundation for a new, transparent taxonomy relies on three elements, which make a clear distinction between processes that describe actions through established routines ('Adherence to medications', 'Management of adherence') and the discipline that studies those processes ('Adherence-related sciences'). 'Adherence to medications' is the process by which patients take their medication as prescribed, further divided into three quantifiable phases: 'Initiation', 'Implementation' and 'Discontinuation'. In response to the proliferation of ambiguous or unquantifiable terms in the literature on medication adherence, this research has resulted in a new conceptual foundation for a transparent taxonomy. The terms and definitions are focused on promoting consistency and quantification in terminology and methods to aid in the conduct, analysis and interpretation of scientific studies of medication adherence.

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.

Bone turnover markers and bone mineral density response with risedronate therapy: relationship with fracture risk and patient adherence

Surrogate markers of fracture risk--bone turnover markers (BTMs) and bone mineral density (BMD)--can be used to monitor treatment response. We assessed whether changes in these markers greater than the least significant change (LSC) were associated with fracture risk reduction and greater adherence. This secondary analysis of the Improving Measurements of Persistence on ACtonel Treatment (IMPACT) study--a multinational prospective, open-label, cluster-randomized study of postmenopausal women on oral risedronate 5 mg/d for 52 weeks-assessed adherence by electronic monitors. Urinary N-terminal cross-linked telopeptide of type 1 collagen (uNTX) and serum C-terminal cross-linked telopeptide of type 1 collagen (sCTX) levels were assessed at baseline and weeks 10 and 22, and BMD at baseline and week 52. Fractures were recorded as adverse events. In 2302 women, responses beyond LSC in BTMs (uNTX and sCTX) and BMD (spine only) were associated with a reduced risk of nonvertebral fractures (NVFs) and all fractures. NVF incidence was about 50% lower in patients with 30% or more of uNTX reduction at week 22 (1.6%) than in those with less than 30% reduction (3.2%, p = .015). NVFs also were reduced in patients with more than 3% spine BMD increase at 52 weeks than those with 3% or less. Responses greater than LSC in BTMs and BMD were associated with greater adherence, but there was no association between adherence and fracture outcomes at 52 weeks. Changes greater than the LSC in BTMs and BMD reflect better treatment adherence, were associated with fracture risk reduction, and identify differences in individual responsiveness to risedronate.

Effects on blood pressure and cardiovascular risk of variations in patients' adherence to prescribed antihypertensive drugs: role of duration of drug action

AIM

To determine the effects of imperfect adherence (i.e. occasionally missing prescribed doses), and the influence of rate of loss of antihypertensive effect during treatment interruption, on the predicted clinical effectiveness of antihypertensive drugs in reducing mean systolic blood pressure (SBP) and cardiovascular disease (CVD) risk.

METHOD

The effects of imperfect adherence to antihypertensive treatment regimens were estimated using published patterns of missed doses, and taking into account the rate of loss of antihypertensive effect when doses are missed (loss of BP reduction in mmHg/day; the off-rate), which varies between drugs. Outcome measures were the predicted mean SBP reduction and CVD risk, determined from the Framingham Risk Equation for CVD.

RESULTS

In patients taking 75% of prescribed doses (typical of clinical practice), only long-acting drugs with an off-rate of ∼1 mmHg/day were predicted to maintain almost the full mean SBP-lowering effect throughout the modelled period. In such patients, using shorter-acting drugs (e.g. an off-rate of ∼5-6 mmHg/day) was predicted to lead to a clinically relevant loss of mean SBP reduction of > 2 mmHg. This change also influenced the predicted CVD risk reduction; in patients with a baseline 10-year CVD risk of 27.0% and who were taking 75% of prescribed doses, a difference in off-rate from 1 to 5 mmHg/day led to a predicted 0.5% absolute increase in 10-year CVD risk.

CONCLUSIONS

In patients who occasionally miss doses of antihypertensives, modest differences in the rate of loss of antihypertensive effect following treatment interruption may have a clinically relevant impact on SBP reduction and CVD risk. While clinicians must make every effort to counsel and encourage each of their patients to adhere to their prescribed medication, it may also be prudent to prescribe drugs with a low off-rate to mitigate the potential consequences of missing doses.