What are validated self-report adherence scales really measuring?: a systematic review

Abstract

AIMSMedication non-adherence is a significant health problem. There are numerous methods for measuring adherence, but no single method performs well on all criteria. The purpose of this systematic review is to (i) identify self-report medication adherence scales that have been correlated with comparison measures of medication-taking behaviour, (ii) assess how these scales measure adherence and (iii) explore how these adherence scales have been validated. METHODSCinahl and PubMed databases were used to search articles written in English on the development or validation of medication adherence scales dating to August 2012. The search terms used were medication adherence, medication non-adherence, medication compliance and names of each scale. Data such as barriers identified and validation comparison measures were extracted and compared. RESULTSSixty articles were included in the review, which consisted of 43 adherence scales. Adherence scales include items that either elicit information regarding the patient's medication-taking behaviour and/or attempts to identify barriers to good medication-taking behaviour or beliefs associated with adherence. The validation strategies employed depended on whether the focus of the scale was to measure medication-taking behaviour or identify barriers or beliefs. CONCLUSIONSSupporting patients to be adherent requires information on their medication-taking behaviour, barriers to adherence and beliefs about medicines. Adherence scales have the potential to explore these aspects of adherence, but currently there has been a greater focus on measuring medication-taking behaviour. Selecting the 'right' adherence scale(s) requires consideration of what needs to be measured and how (and in whom) the scale has been validated.

Self-report measures of medication adherence behavior: recommendations on optimal use

“…To help improve available information on measures, adherence-related publications should include a clear description of any self-report measure and its administration method, along with descriptive data resulting from the measure (e.g., mean, median, standard deviation) [9,35]. Define the adherence construct you want to assess-It is important to define the specific construct of interest when conducting medication adherence assessments and to select an appropriately corresponding measure [7,52,59,60]. Voils and colleagues [12,52,61] have argued that self-report adherence measures often conflate two distinct constructs-the extent of nonadherence and reasons for nonadherence-and this conflation may be one factor that has limited the psychometric properties and validity of many existing self-report measures.…”

“…Stated simply, self-reports of nonadherence can be trusted; self-reports of adherence less so. Osterberg and Blaschke [10] explained that Ba patient who admits to poor adherence is generally being candid. review of self-report measures found that only 12 of 43 scales reported sensitivity and specificity data [7]. Sensitivity and specificity may be infrequently calculated because it requires comparison with a Bgoldstandard^clinical outcome or adherence measure, as well as establishment of an appropriate cut-off for determining nonadherence-and there is lack of 1.…”

“…Second, there is a paucity of research on how to optimize the validity of self-report adherence measures in clinical care or health research. The myriad of self-report adherence measures that are available in the research literature contain substantial variation in their question phrasing, response scale formats, time intervals for recall, and modes of administration [1,5,7,8]. Few studies have empirically tested the comparative validity of these varied methodologic choices [9], and most selfreport adherence measures have only been validated within single areas of chronic illness [7].…”

“…The myriad of self-report adherence measures that are available in the research literature contain substantial variation in their question phrasing, response scale formats, time intervals for recall, and modes of administration [1,5,7,8]. Few studies have empirically tested the comparative validity of these varied methodologic choices [9], and most selfreport adherence measures have only been validated within single areas of chronic illness [7].This paper reviews the current evidence-base behind self-report measures of medication adherence with an eye toward optimizing their selection and use. The paper was the result of the deliberation of a panel of medication adherence research experts from across the disease spectrum, which was assembled by the NIH Adherence Network-a consortium of science officers working at many different NIH institutes, centers, and offices.…”

“…These measures are defined by asking respondents to characterize their medication adherence behavior. Self-report measures of medication adherence range from simple singleitem questions regarding missed doses to complex multi-item assessments that incorporate reasons for nonadherence [7]. The widespread use of self-report adherence measures in clinical care and research reflects their low cost and ease of implementation across a large variety of medication regimens.…”