The validity and reliability of the diabetes health profile (DHP) in NIDDM patients referred for insulin therapy

Recently, a new diabetes-specific questionnaire, the Diabetes Health Profile (DHP), has been developed to identify psychosocial dysfunctioning of insulin-requiring (NIDDM) and insulin-dependent diabetes mellitus (IDDM) patients. The DHP comprises three dimensions: psychological distress (PSY: 14 items), barriers to activity (BAR: 12 items) and disinhibited eating (EAT: five items). This study investigates the psychometric properties of the DHP in Dutch noninsulin-dependent diabetes mellitus (NIDDM) patients referred for insulin therapy. In addition, the relationship between patient characteristics and the DHP outcome was examined. The factor structure found was similar but not identical to former studies, but construct validity was supported by high correlations of our factor structure and the original factor outcome and Cronbach's alpha. The three factors explained 32% of the variance, supporting earlier findings. It was shown that Cronbach's alpha was satisfactory (0.72, 0.72 and 0.79). Convergent validity showed strong and significant correlations between the PSY/BAR dimensions and predicted corresponding scales of the RAND-36. However, the PSY/BAR dimensions also showed, although less strong, significant correlations with the non-corresponding RAND-36 scales. The EAT dimension showed only correlations with two of the RAND-36 dimensions, thus measuring a different trait. Regression analysis showed that older patients had less problems with items of the EAT dimension and that no difference was found between men and women, supporting earlier findings. The hyperglycaemic complaint 'fatigue' gave a significantly lower score (more problems) on the PSY and BAR dimensions. Younger age, the presence of hypertension and retinopathy resulted in a significantly lower score on the EAT dimension. DHP outcome was not significantly influenced by duration of diabetes, HbA(1c) (indicator of glycemic control), serum total cholesterol, body mass index, chronic diabetes complications and comorbidity. Overall, the psychometric properties were good considering the small and diverse sample, suggesting that the DHP is promising for use in NIDDM patients, although more study is necessary in a larger sample.