Development and testing of the Hill-Bone Compliance to High Blood Pressure Therapy Scale

Abstract

The Hill-Bone Compliance to High Blood Pressure Therapy Scale assesses patient behaviors for three important behavioral domains of high blood pressure treatment: 1) reduced sodium intake; 2) appointment keeping; and 3) medication taking. This scale is comprised of 14 items in three subscales. Each item is a four point Likert type scale. The content validity of the scale was assessed by a relevant literature review and an expert panel, which focused on cultural sensitivity and appropriateness of the instrument for low literacy. Internal consistency reliability and predictive validity of the scale were evaluated using two community based samples of hypertensive adults enrolled in clinical trials of high blood pressure care and control. The standardized alpha for the total scale were 0.74 and 0.84, and the average interitem correlations of the 14 items were 0.18 and 0.28, respectively. The construct and predictive validity of the scale was assessed by factor analysis and by testing of theoretically derived hypotheses regarding whether the scale demonstrated consistent and expected relationships with related variables. In this study, high compliance scale scores predicted significantly lower levels of blood pressure and blood pressure control. Moreover, high compliance scale scores at the baseline were significantly associated with blood pressure control at both baseline and at follow up in the two independent samples. This brief instrument provides a simple method for clinicians in various settings to use to assess patients' self reported compliance levels and to plan appropriate interventions.