Skin hydration of the heel with fissure in patients with diabetes: a cross-sectional observational study

Abstract

Purpose: Foot fissure should be prevented in patients with diabetes due to the likelihood of subsequent diabetic ulcer. The purpose of this study was to investigate a cutoff point for skin hydration with fissure and the factors associated with low skin hydration in patients with diabetes. Subjects and methods: Subjects were patients with diabetes who visited the diabetic foot clinic and were evaluated for skin hydration on the heel between April 2008 and March 2015. Information about fissure, skin hydration, age, sex, autonomic neuropathy, angiopathy, and tinea pedis were collected from the medical charts. Skin hydration on the heel was measured using a moisture checker. Skin hydration was compared between heels with and without fissure, and a cutoff for skin hydration with fissure was determined using receiver operating characteristic analysis. Based on the determined cutoff, factors associated with lower skin hydration were analyzed using logistic regression analysis. Results: Participants comprised 693 patients. Mean ± SD age was 66.8 ± 10.8 years, and 57.0% of subjects were male. The frequency of fissures on the heels was 10.4%. Area under the receiver operating characteristic curve for skin hydration in the presence of fissure was 0.717. Twenty percent was selected as the cutoff point, offering sensitivity of 0.478 and specificity of 0.819. Logistic regression analysis showed correlations between three factors (male sex, tinea pedis, and room temperature) and skin hydration < 20.0% (odds ratio [OR] 1.587, 95% CI 1.157–2.178, p = 0.004; OR 1.548, 95% CI 1.122–2.135, p = 0.005; and OR 0.900, 95% CI 0.823–0.0985, p = 0.021, respectively). Conclusion: To prevent heel fissures, moisturizing care should aim at achieving skin hydration of 20%. If skin hydration is < 20%, prevention of fissures may warrant not only specialized moisturizing care but also consideration of treatment for tinea pedis.