Validity and reliability of a short self-efficacy instrument for hypertension treatment adherence among adults with uncontrolled hypertension

Abstract

ObjectiveTo establish the reliability and validity of a self-report measure designed to assess self-efficacy for hypertension treatment adherence. MethodsThis investigation was embedded within a six-month randomized clinical trial (RCT), which demonstrated that a tailored, stage-matched intervention was more effective at improving hypertension control than usual care among individuals (n = 533) with repeated uncontrolled hypertension. The instrument used to assess self-efficacy for hypertension treatment adherence (SE-HTA) comprised three subscales that assessed diet self-efficacy (DSE), exercise self-efficacy (ESE), and medication self-efficacy (MSE). To determine SE-HTA validity and reliability, we assessed internal consistency using Cronbach’s α coefficients, conducted exploratory factor analysis, and evaluated convergent and discriminant validity, as well as test-retest reliability using Spearman’s ρ correlation coefficients. ResultsCronbach’s α (internal consistency) values for DSE, ESE, and MSE were 0.81, 0.82 and 0.74. Factor analysis and the scree plot demonstrated three distinct factors, which correspond to the three subscales contained in the SE-HTA instrument. SE-HTA possessed good convergent and discriminant validity, and moderate test-retest reliability. ConclusionThe SE-HTA instrument containing diet, exercise, and medication adherence subscales is valid and reliable in adults with uncontrolled hypertension. Practice implicationsThis SE-HTA instrument measures self-efficacy and could help facilitate behavior change in hypertension.