Development and psychometric evaluation of the belief and attitude about herbal medicine inventory among iranian patients with cardiovascular disease

Background: Over-the-counter use of herbal products puts patients with cardiovascular diseases (CVDs) at risk for drug interactions. Belief and attitude have significant effects on behavior. Objectives: This study was conducted to develop and evaluate the psychometric properties of the Belief and Attitude about Herbal Medicine Inventory (BAHMI). Methods: In this methodological study, the BAHMI draft was developed based on the approach of Waltz and colleagues and using the existing instruments and the three main theory of planned behavior subscales. After face and content validity assessment, BAHMI construct and concurrent validity were assessed. Accordingly, 200 patients with CVD were consecutively recruited from a heart clinic in Kashan, Iran, 2018. BAHMI reliability was also assessed through the internal consistency and the test–retest methods. Results: The BAHMI draft included 40 items. Seven items were excluded during psychometric evaluation phases. Exploratory factor analysis revealed a five-factor structure for BAHMI which explained 42.636% of the variance of its total score. The correlation coefficient between the scores of BAHMI and Hashem-Dabaghian and colleagues' questionnaire was –0.7 (P < 0.0001). BAHMI mean score was significantly different among patients with different levels of agreement on herbal product use (F = 19.16, P < 0.0001). Cronbach's alpha, intraclass correlation coefficient, standard error of measurement, and smallest detectable change of BAHMI were 0.864, 0.888, ±13.46, and 10.2, respectively. No participant obtained the minimum and maximum possible BAHMI scores. Conclusion: The 33-item BAHMI is a valid and reliable instrument for the assessment of belief and attitude about herbal medicine among patients with CVD. The findings of this study can be used for health policy-making and planning.