Correlation between adherence rates measured by MEMS and self-reported questionnaires: a meta-analysis

Abstract

PurposeIt is vital to understand the associations between the medication event monitoring systems (MEMS) and self-reported questionnaires (SRQs) because both are often used to measure medication adherence and can produce different results. In addition, the economic implication of using alternative measures is important as the cost of electronic monitoring devices is not covered by insurance, while self-reports are the most practical and cost-effective method in the clinical settings. This meta-analysis examined the correlations of two measurements of medication adherence: MEMS and SRQs.MethodsThe literature search (1980-2009) used PubMed, OVID MEDLINE, PsycINFO (EBSCO), CINAHL (EBSCO), OVID HealthStar, EMBASE (Elsevier), and Cochrane Databases. Studies were included if the correlation coefficients [Pearson (rp) or Spearman (rs)] between adherences measured by both MEMS and SRQs were available or could be calculated from other statistics in the articles. Data were independently abstracted in duplicate with standardized protocol and abstraction form including 1) first author's name; 2) year of publication; 3) disease status of participants; 4) sample size; 5) mean age (year); 6) duration of trials (month); 7) SRQ names if available; 8) adherence (%) measured by MEMS; 9) adherence (%) measured by SRQ; 10) correlation coefficient and relative information, including p-value, 95% confidence interval (CI). A meta-analysis was conducted to pool the correlation coefficients using random-effect model.ResultsEleven studies (N = 1,684 patients) met the inclusion criteria. The mean of adherence measured by MEMS was 74.9% (range 53.4%-92.9%), versus 84.0% by SRQ (range 68.35%-95%). The correlation between adherence measured by MEMS and SRQs ranged from 0.24 to 0.87. The pooled correlation coefficient for 11 studies was 0.45 (p = 0.001, 95% confidence interval [95% CI]: 0.34-0.56). The subgroup meta-analysis on the seven studies reporting rp and four studies reporting rs reported the pooled correlation coefficient: 0.46 (p = 0.011, 95% CI: 0.33-0.59) and 0.43 (p = 0.0038, 95% CI: 0.23-0.64), respectively. No differences were found for other subgroup analyses.ConclusionMedication adherence measured by MEMS and SRQs tends to be at least moderately correlated, suggesting that SRQs give a good estimate of medication adherence.

Individualised patient care as an adjunct to standard care for promoting adherence to ocular hypotensive therapy: an exploratory randomised controlled trial

“…A meta-analysis found self-report to be a good estimate of patient adherence when compared with electronic monitoring. 39 The good correlation between self-report and refill adherence found in our study and reported elsewhere [40][41][42] supports the validity of these two measures. In combination, they can assist in achieving an accurate measure for patient adherence.…”

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

“…Among comparisons that were not highly concordant, self-reports produced higher estimates of adherence than other assessment methods 92 % of the time (45 out of 49 comparisons). A meta-analysis showed the estimated degree of regimen execution is approximately 15 % higher by self-report when compared with EDM devices [56], which is consonant with estimates in other reviews and syntheses [5,35,56,58].…”

“…In a review of 41 medication adherence studies, Shi and colleagues [55] determined that a majority of studies (68 %) report correlations between self-report and EDM adherence measures that are either high (27 %), moderate (29 %), or low yet statistically significant (12 %). A related metaanalysis estimated that the pooled correlation coefficient between self-report and electronically monitored adherence was 0.45 (95 % CI, 0.34-0.56) [56].…”

“…In a review of 41 medication adherence studies, Shi and colleagues [55] determined that a majority of studies (68 %) report correlations between self-report and EDM adherence measures that are either high (27 %), moderate (29 %), or low yet statistically significant (12 %). A related metaanalysis estimated that the pooled correlation coefficient between self-report and electronically monitored adherence was 0.45 (95 % CI, 0.34-0.56) [56].Moderate correlations between self-report and electronic monitoring reflect the performance of both adherence measures, and as such, may reflect limitations in self-reports as well as logistic challenges in EDM [57].Research on the convergent validity of self-report adherence measures shows clear evidence that they tend to overestimate the extent of regimen execution relative to other adherence assessments [32,46]. In an examination of 57 studies across many chronic illnesses, Garber and colleagues [8] found high concordance between selfreport and other adherence assessments in 43 % of comparisons.…”

“…Among comparisons that were not highly concordant, self-reports produced higher estimates of adherence than other assessment methods 92 % of the time (45 out of 49 comparisons). A meta-analysis showed the estimated degree of regimen execution is approximately 15 % higher by self-report when compared with EDM devices [56], which is consonant with estimates in other reviews and syntheses [5,35,56,58].Sensitivity and specificity-Because of potential overreporting, self-report adherence measures are considered to have good specificity (i.e., positive predictive value) and weak sensitivity (i.e., negative predictive value) for detecting poor adherence [5,32,46]. Stated simply, self-reports of nonadherence can be trusted; self-reports of adherence less so.…”