Obstructive sleep apnea risk and its association with diabetic foot ulcer in patients with type 2 diabetes

Obstructive sleep apnea (OSA) is common in type 2 diabetes (T2D) and may contribute to its chronic complications. Whether STOP-Bang-defined OSA risk is associated with diabetic foot ulcer (DFU) severity and outcome remains unclear. We compared STOP-Bang score between T2D patients with and without DFU and explored the association between OSA risk and DFU severity and healing.

We conducted an observational study with a cross-sectional matched case-control comparison including 73 T2D patients with DFU and 73 T2D controls without DFU, matched by age, HbA1c, BMI and smoking. At the study visit, STOP-Bang-defined OSA risk was assessed as a continuous score and categorized as low versus moderate/high risk. In the DFU group, ulcer severity was graded at the same visit with the WIfI classification, and time to healing and amputation was recorded during clinical follow-up. Multivariable logistic regression identified predictors of moderate-to-high amputation risk.

In unadjusted analyses, DFU patients had higher STOP-Bang score than controls (4.3 ± 2.0 vs. 3.2 ± 2.2, p=0.004) and more often intermediate/high OSA risk (83.6% vs. 60.3%, p=0.002), although these differences were attenuated after accounting for sex imbalance. Among DFU patients, higher ulcer severity was associated with moderate/high STOP-Bang-defined OSA risk (97.1 vs. 71.8%; p=0.004). Median healing time was longer in those with moderate/high versus low STOP-Bang-defined OSA risk (120.0 vs. 65.0 days, p=0.032). In multivariable analysis, WIfI ulcer severity was associated with male sex, higher STOP-Bang category and poorer metabolic control.

STOP-Bang-defined OSA risk was associated with greater DFU severity and delayed wound healing. Incorporating OSA risk stratification into routine assessment of patients with DFU may help identify individuals at higher risk of poor outcomes.