The Diabetes Health Profile (DHP): A New instrument for assessing the psychosocial profile of insulin requiring patients ? Development and psychometric evaluation

Abstract

The aim of the studies was to evaluate the psychometric properties and construct validity of the Diabetes Health Profile (DHP-1). Content for the DHP-1 was derived following in-depth interviews with 25 insulin dependent and insulin requiring patients, a review of the literature and discussions with health care professionals. Initial analysis of the factor structure of the DHP-1 was carried out on the responses of 239 insulin dependent and insulin requiring patients, with a mean age of 40.85 years (SD=13.0), resulting in a 43 item three factor solution. The 43 item version of the DHP-1 was completed by 2,239 insulin dependent/requiring patients (mean age = 39.8, SD=10) years. Fifty-one per cent were men. A forced three factor Principal Factoring Analysis with varimax rotation was carried out. Eleven items were excluded with item factor cross loadings >0.30 or item factor loadings <0.30. PAF analysis of the 32 items resulted in a three factor solution accounting for 33% of the total explained variance. The three factors were interpreted as Psychological Distress, Barriers to Activity and Disnhibited Eating. Factor congruence between subsamples were: Psychological distress (0.93), Barriers to Activity (0.93) and Disinhibited Eating (0.99). Coefficients of congruence between men and women were 0.94, 0.92 and 0.99 for Psychological Distress, Barriers to Activity and Disinhibited Eating respectively. Internal consistency of the three factors (Cronbach's α) were: Psychological Distress (0.86), Barriers to Activity (0.82), and Disinhibited Eating (0.77). Construct-convergent validity was investigated on a sample of 233 insulin dependent and insulin requiring patients (mean age = 51.46 years). Psychological Distress and Barriers to Activity subscales correlated with the Hospital Depression and Anxiety Scale = 0.50 to 0.62, p<0.01 and subscales of the SF-36 (range: r=−0.17 to -0.62, p<0.01). These findings lend support to the construct validity and reliability of the DHP-1 and that it is suitable for further development.