Development, Reliability, and Validity of the Home Blood Pressure Monitoring Adherence Scale for Patients with Chronic Kidney Disease

BACKGROUND: Home blood pressure monitoring helps patients with chronic kidney disease to improve blood pressure control and can predict cardiovascular events, renal function progress, and risk of death. Few instruments are available to assess patient adherence to home blood pressure monitoring. OBJECTIVE: The aim of the study was to develop an instrument to evaluate home blood pressure monitoring adherence in patients with chronic kidney disease and test its reliability and validity. METHODS: An item pool was formed for the Home Blood Pressure Monitoring Adherence Scale by literature review. Patients with chronic kidney disease (n = 436) were surveyed to assess item selection and examine item reliability and validity. Scale reliability was evaluated using internal, split-half, and test–retest reliability, while validity was assessed according to content, construct, and criterion validity. RESULTS: The scale comprising eight items was formed from the item pool and item selection. Cronbach’s α was 0.906, split-half reliability was 0.947, and test–retest reliability was 0.716. Item-level and scale-level (both universal agreement and average) content validity indices were 1.00. According to the Self-Efficacy for Managing Chronic Disease 6-item Scale, criterion validity for our scale was 0.251. Exploratory factor analysis extracted one factor and the cumulative variance contribution rate was 61.568%. Confirmatory factor analysis showed the model fit well (Χ(2)=50.125, df=17, Χ(2)/df=2.949, root mean square error of approximation=0.095, confirmatory fit index=0.970). CONCLUSION: The scale has good reliability and validity for patients with chronic kidney disease, representing an efficient instrument for clinical assessment of home blood pressure monitoring adherence.