What is known and objectives: Adherence has proved to have a positive influence on achieving plausible treatment outcomes. Self-report questionnaires are widely used in evaluating adherence, creating thus a high-powered research field. This review aims to provide an update of scales used in hypertension, which are compared and analysed against reliability and validity.
Methods: PubMed, Web of Science and Cochrane Library were searched in May 2022 to identify studies. We extracted the study characteristics and evaluated their quality. A random-effects model with subgroup analysis was used to calculate estimates and heterogeneity parameters as well as regressions, funnel and forest plots. A bivariate model was selected to conduct validity analyses and draw receiver operating characteristic (ROC) curves.
Results and discussion: Fifty-five articles were identified and classified into 22 different reliable and validated tools. Pooled analyses predicted an overall good Cronbach's alpha of 0.76 (95%CI:0.67-0.83), a good ICC of 0.8 (95%CI:0.72-0.86) and an excellent correlation coefficient of 0.91 (95%CI:0.86-0.95), which all showed high heterogeneity and slight detection of asymmetry. Regression analyses showed that only time and the number of items/scale type influenced significantly retest and alpha, respectively. Overall validity showed acceptable sensitivity of 0.65 (95%CI:0.53-0.75) and specificity of 0.57 (95%CI:0.47-0.67) with a good Area Under Curve (AUC) of 0.637. Upon comparison, four tools showed superiority over Morisky's scale.
What is new and conclusion: Adherence is a multi-dimensional phenomenon, which deems scales to be highly variable or complex; thus, complicating the selection process. Adherence to Refills and Medications Scale (ARMS) is the most promising free non-inferior alternative to Morisky, the most used scale.
Keywords: Cronbach's alpha; adherence; hypertension; meta-analysis; review; scales; stability; tools; validity.
© 2022 John Wiley & Sons Ltd.