Development of a scale to assess the compliance of hypertensive patients.

The purpose of this paper is to describe the development of the "Compliance of Hypertensive Patients" scale (=CHPS), and assessment of its reliability and validity. Previous scales incorporate only activity in health regimens as indicators of hypertensive patients' compliance. The "Compliance of Hypertensive Patients" scale was developed to incorporate other indicators of compliance also, such as intention, responsibility and collaboration. Data were collected from a convenience sample of 103 patients, in five health care centres in Finland. Dimensionality was explored using principal component analysis and internal consistency was estimated according to a standard item analysis approach and Theta coefficient. Validity was assessed using face validity, content validity and criterion-related validity (through the use of concurrent validity). The data supported five subscales, labelled: lifestyle, intention, attitude, responsibility and smoking. Inter-item correlations ranged from 0.24 to 0.61 and corrected item-total correlations from 0.32 to 0.67, across subscales. The Theta coefficient demonstrated good internal consistency. This scale forms a useful starting point in the development of a reliable and valid tool to assess compliance of hypertensive patients, based on several indicators.