Elevated obstructive sleep apnoea risk score is associated with poor healing of diabetic foot ulcers: a prospective cohort study

Aims To assess the prevalence of risk factors for obstructive sleep apnoea in people with diabetic foot ulcers and to determine whether this risk predicts diabetic foot ulcer healing. MethodsResultsWe studied 94 consecutive people (69% men) with diabetic foot ulcers (Type 2 diabetes, n=66, Type 1 diabetes, n=28) attending a university hospital foot unit. All participants were screened for obstructive sleep apnoea using the STOP-BANG questionnaire, with a score 4 identifying high risk of obstructive sleep apnoea. The primary outcome was poor diabetic foot ulcer healing, defined as diabetic foot ulcer recurrence (diabetic foot ulcers which healed and re-ulcerated in same anatomical position) and/or diabetic foot ulcer persistence (no evidence of healing on clinical examination). All participants were evaluated at 12 months. Of the 94 participants, 60 (64%) had a STOP-BANG score 4. Over 12 months, 27 participants with a score 4 had poor diabetic foot ulcer healing as compared to seven with a score <4 (45% vs 20.5%; P=0.025). A STOP-BANG score 4 significantly increased the relative risk of poor healing more than twofold, independently of other risk factors in multivariable analyses. ConclusionsWhat's new?There is a high prevalence of features and risk of obstructive sleep apnoea in people with diabetic foot ulcers. A STOP-BANG score 4 predicts poor diabetic foot ulcer healing. Obstructive sleep apnoea may be a potential, modifiable risk factor/treatment target to improve diabetic foot ulcer outcomes. The impact of risk factors for obstructive sleep apnoea (OSA) on diabetic foot ulcer healing is unknown. We describe for the first time a high prevalence (60%) of risk factors for OSA in patients with diabetic foot ulcers. We also report in this prospective study the novel finding that a high risk of OSA predicts, independently of traditional risk factors, a more than twofold increased risk of poor diabetic foot ulcer healing. Our results support the hypothesis that OSA is a potential, modifiable risk factor/treatment target to improve diabetic foot ulcer outcomes.