Development, validation and psychometric analysis of the diabetic foot self-care questionnaire of the University of Malaga, Spain (DFSQ-UMA).

This paper assessed the reliability and construct validity of a tool to evaluate the foot self-care of diabetic patients. The education of diabetic patients about their foot care is a major issue to avoid complications like amputations and ulcers. Specific tools aimed to assess patient's knowledge in this area are needed. The study had two phases: in Phase 1, item-generation was carried out through a literature review, expert review by a Delphi technique and cognitive interviews with diabetic patients for testing readability and comprehension. In Phase 2, diabetic patients participated in a cross-sectional study for a psychometric evaluation (reliability and construct validity) was carried out on a sample of type I and II diabetic patients. The study was conducted at the University of Malaga (Spain), podiatric clinics and a Diabetic Foot Unit between October 2012 and March 2013. After psychometric-test analyses on a sample of 209 diabetic patients, the questionnaire resulted in 16 questions. Cronbach's alpha was 0.89 after removing 4 items because of their low reliability. Inter-item correlations gave a mean value of 0.34 (range: 0.06-0.74). The rotated solution showed a 3-factor structure (self-care, foot care, and footwear and socks) that jointly accounted for 60.88% of the variance observed. The correlation between the questionnaire scores and HbA1c was significant and inverse, (r = -0.15; p < 0.01). The findings show that the questionnaire is a valid and reliable tool for evaluating foot self-care behavior in diabetic patients.