Development and psychometric evaluation of the Treatment Adherence Questionnaire for Patients with Hypertension

Abstract

Aim: This article is a report of the development and psychometric testing of the Treatment Adherence Questionnaire for Patients with Hypertension.

Background: Hypertension is the most prevalent health problem among adult patients affecting approximately 200 million people in China and about 1 billion persons worldwide. Adherence to medication and lifestyle for hypertensive patients result in blood pressure control and reduce adverse outcomes. At present, few specific adherence instruments are available to completely evaluate medication and lifestyle for hypertensive patients.

Methods: A multi-phase psychometric questionnaire development method was used to develop the instrument. The item pool was generated using literature review and focus group. Content validity was evaluated by expert panel. Then, the field testing was conducted by a convenience sampling of 278 hypertensive patients from December 2009 to May 2010 in Guangdong Province of China. Exploratory and confirmatory factor analyses were used to test construct validity. Finally, internal consistency and test-retest reliability were assessed.

Results: The new measure consisted of six dimensions with 28 items, explaining 62·54% of the total variance in the data. Confirmative factor analysis supported a good overall fit of the six-factor model. Cronbach's α of the overall questionnaire was 0·86 and 0·82 for test-retest reliability.

Conclusions: The questionnaire was a brief and psychometrically sound instrument to evaluate hypertensive patients' treatment adherence and to be applied in the research and clinical fields.