development and psychometric evaluation of a health action process approach inventory for healthful diet among type 2 diabetes patients

background: long‑term effects of diabetes could be prevented or delayed by adopting a proper diet. the aim of this study was to adapt and provide a pilot test using health action process approach (hapa)‑based inventory to capable of capturing significant determinants of healthful diet for diabetics. methods: the inventory was reviewed by eight diabetes patients and verbal feedbacks with regard the comprehension, item relevance, and potential new content were obtained. then, the inventory items were evaluated by an expert panel. next exploratory factor analysis (efa) was conducted to assess the scale constructs. criterion validity was measured by pearson correlation. finally, reliability measures of internal consistency and test‑retest analysis were determined. results: a total of 121 diabetic patients participated in this study. efa extracted seven factors (risk‑perception, action self‑efficacy, outcome expectancies, maintenance self‑efficacy, action and coping planning, behavioral intention, and recovery self‑efficacy) explaining 81.14% of the total variance. there were significant correlations between behavioral intentions and both outcome expectancies (r = 0.55, p < 0.05) and action self‑efficacy (r = 0.31, p < 0.004) and small to moderate correlations (rs = 23–40) between behavior and the volitional constructs of the hapa model. cronbach’s alpha ranging from 0.65 to 0.95 and intraclass correlation coefficients ranging from 0.71 to 0.92 indicated an acceptable internal consistency. conclusions: developed scales were valid and reliable for measuring hapa variables to be used with type 2 diabetes mellitus patients. further examination with minority persons is warranted.