Measuring Medication Adherence
Measuring Medication Adherence
Objective: To evaluate literature describing medication adherence surveys/scales to gauge patient behaviors at the point of care.
Data sources: Literature was identified via PubMed and Ovid (1950 to June 2009) using the search terms medication adherence, medication compliance, and medication persistence and combined with the terms questionnaire, survey, scale, or self-report.
Study selection: All articles in English with adherence scales validated in two or more diseases and containing 30 or fewer questions were selected.
Data synthesis: Five adherence scales were identified and reviewed by evaluating positive characteristics (short length, internal consistency, reliability, barriers to adherence, literacy appropriate, and self-efficacy), sensitivity, specificity, and diseases in which they have been validated. The Medication Adherence Questionnaire (MAQ) is the shortest scale and easiest to score. MAQ identifies barriers to nonadherence but not self-efficacy. The Self-efficacy for Appropriate Medication Use Scale (SEAMS) is a 13-question scale, and the Brief Medication Questionnaire (BMQ) has three main question headings and multiple subquestions. Both assess barriers and self-efficacy; however, scoring is difficult. The Hill-Bone Compliance Scale and Medication Adherence Rating Scale (MARS) address barriers and self-efficacy but are limited in their generalizability. The Hill-Bone Compliance Scale focuses on hypertensive patients, while MARS is specific to psychiatric populations.
Conclusion: No gold-standard medication adherence scale exists. MAQ is most adaptable at the point of care and across populations. MAQ is the quickest to administer and score and has been validated in the broadest range of diseases. SEAMS, BMQ, and the Hill-Bone Compliance Scale allow self-efficacy to be assessed and therefore may be useful in medication management clinics. MARS is specific to psychiatric populations.
Medication adherence is the extent to which patients take medications as prescribed by their health care providers and as agreed upon in the treatment plan. Medication adherence is essential to optimizing patient outcomes in nearly any disease. Nonadherence to medications is associated with worsening of disease, increased mortality, and greater health care costs. Direct and indirect methods are available to assess medication adherence. Direct methods include observing patients taking medications and measuring drug or metabolite concentrations in the blood or urine. Indirect methods include asking patients, patient diaries, refill rates, pill counting, monitoring for clinical response, electronic monitoring devices, and patient scales or surveys. Estimates indicate that only 50% to 60% of patients are adherent to prescribed medication(s) during a 1-year period. Despite this commonality, clinician awareness of medication nonadherence is limited, resulting in a need to readily identify adherence-related behaviors at the point of care.
Medication adherence scales or surveys are simple and low-cost approaches to identifying medication nonadherence in clinical practice. For simplification purposes, this report will refer to any patient survey, scale, or questionnaire that assesses medication adherence as an adherence scale. A number of validated medication adherence scales have been described in the literature; however, no gold standard exists, and no single scale is appropriate for every scenario. Factors to consider in selecting an adherence scale include administration length, internal consistency reliability (i.e., ability to judge consistency across results of survey items; clinical threshold defined as ≥0.7 of 1-point scale), ability to detect barriers to adherence, validation in low-literacy patients (i.e., less than high school education or sixth grade reading level), ability to assess self-efficacy (i.e., belief in one's ability to achieve a goal or outcome), sensitivity (i.e., likelihood of detecting nonadherence if present), and specificity (i.e., likelihood of not detecting nonadherence if not present), as well as the diseases in which it has been validated (Table 1).
Abstract and Introduction
Abstract
Objective: To evaluate literature describing medication adherence surveys/scales to gauge patient behaviors at the point of care.
Data sources: Literature was identified via PubMed and Ovid (1950 to June 2009) using the search terms medication adherence, medication compliance, and medication persistence and combined with the terms questionnaire, survey, scale, or self-report.
Study selection: All articles in English with adherence scales validated in two or more diseases and containing 30 or fewer questions were selected.
Data synthesis: Five adherence scales were identified and reviewed by evaluating positive characteristics (short length, internal consistency, reliability, barriers to adherence, literacy appropriate, and self-efficacy), sensitivity, specificity, and diseases in which they have been validated. The Medication Adherence Questionnaire (MAQ) is the shortest scale and easiest to score. MAQ identifies barriers to nonadherence but not self-efficacy. The Self-efficacy for Appropriate Medication Use Scale (SEAMS) is a 13-question scale, and the Brief Medication Questionnaire (BMQ) has three main question headings and multiple subquestions. Both assess barriers and self-efficacy; however, scoring is difficult. The Hill-Bone Compliance Scale and Medication Adherence Rating Scale (MARS) address barriers and self-efficacy but are limited in their generalizability. The Hill-Bone Compliance Scale focuses on hypertensive patients, while MARS is specific to psychiatric populations.
Conclusion: No gold-standard medication adherence scale exists. MAQ is most adaptable at the point of care and across populations. MAQ is the quickest to administer and score and has been validated in the broadest range of diseases. SEAMS, BMQ, and the Hill-Bone Compliance Scale allow self-efficacy to be assessed and therefore may be useful in medication management clinics. MARS is specific to psychiatric populations.
Introduction
Medication adherence is the extent to which patients take medications as prescribed by their health care providers and as agreed upon in the treatment plan. Medication adherence is essential to optimizing patient outcomes in nearly any disease. Nonadherence to medications is associated with worsening of disease, increased mortality, and greater health care costs. Direct and indirect methods are available to assess medication adherence. Direct methods include observing patients taking medications and measuring drug or metabolite concentrations in the blood or urine. Indirect methods include asking patients, patient diaries, refill rates, pill counting, monitoring for clinical response, electronic monitoring devices, and patient scales or surveys. Estimates indicate that only 50% to 60% of patients are adherent to prescribed medication(s) during a 1-year period. Despite this commonality, clinician awareness of medication nonadherence is limited, resulting in a need to readily identify adherence-related behaviors at the point of care.
Medication adherence scales or surveys are simple and low-cost approaches to identifying medication nonadherence in clinical practice. For simplification purposes, this report will refer to any patient survey, scale, or questionnaire that assesses medication adherence as an adherence scale. A number of validated medication adherence scales have been described in the literature; however, no gold standard exists, and no single scale is appropriate for every scenario. Factors to consider in selecting an adherence scale include administration length, internal consistency reliability (i.e., ability to judge consistency across results of survey items; clinical threshold defined as ≥0.7 of 1-point scale), ability to detect barriers to adherence, validation in low-literacy patients (i.e., less than high school education or sixth grade reading level), ability to assess self-efficacy (i.e., belief in one's ability to achieve a goal or outcome), sensitivity (i.e., likelihood of detecting nonadherence if present), and specificity (i.e., likelihood of not detecting nonadherence if not present), as well as the diseases in which it has been validated (Table 1).
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