Patient reported adherence to hypertension treatment: A revalidation study

Background: Adherence to hypertension management in patients with hypertension is known to influence their blood pressure control. It is important to measure patients' adherence behaviours to assist with designing appropriate interventions to improve blood pressure control. Aims: The purposes of this study were to use confirmatory factor analysis to revalidate the Therapeutic Adherence Scale for Hypertensive Patients (TASHP), and to calculate the cut-off score for classifying adherence behaviours into two groups: satisfactory and low adherence behaviours. Methods: Systematic random sampling was used to recruit patients with hypertension in China. Demographic characteristics, the TASHP and blood pressure were collected. The psychometric tests of the TASHP included: construct validity, criteria-related validity, internal reliability, and split-half reliability. The area under the receiver operating characteristics curve and Youden index were used to identify the cut-off score of the TASHP for blood pressure control. Results: This study involved 366 patients. Confirmatory factor analysis supported the four-component structure of the TASHP proposed in the original scale development study. The TASHP has a satisfactory internal reliability (Cronbach's > 0.7) and a satisfactory split-half reliability (Spearman-Brown coefficients > 0.7). The patients with overall scores of the TASHP 109 points were considered to have satisfactory adherence behaviours. Conclusion: The TASHP is a validated and reliable instrument to measure the adherence to hypertension management in Chinese patients with hypertension. The cut-off score of 109 points can be considered as an effective measure to classify the level of adherence into satisfactory and low adherence behaviours.