Background: Patients with diabetic foot ulcers (DFUs) experience large burdens of morbidity, mortality, and hospital costs. Over a third of patients with diabetes will develop DFUs in their lifetime; and almost half of these patients subsequently develop diabetic foot infections (DFIs). Although it has been reported that obese patients with diabetes do not have higher in-hospital mortality, no studies have evaluated the association between morbid obesity and DFUs/DFIs in hospitalized patients.
Methods: Using the 2014 National Inpatient Sample data base, we identified adults with a principal diagnosis of DFUs or DFIs and stratified them into morbidly obese and non-morbidly obese, with a primary outcome of lower limb amputations. Secondary outcomes included: inpatient mortality, hospital costs and length of stay. Outcomes were adjusted for confounders via multivariable regression analyses.
Results: A total of 31,730 individuals with a primary diagnosis of DFU or DFI were included in this study. Morbidly obese patients made up 20% of these cases. Compared to non-morbidly obese patients, the adjusted odds of inpatient mortality among the morbidly obese was 3.89 (95% Confidence Interval (CI): 0.78-19.2, p= 0.096). Both groups also had similar odds for major amputations (p=0.983). Morbidly obese patients had lower odds of minor amputation (aOR: 0.54; 95% CI 0.43-0.79, p=0.001), longer lengths of stays (adjusted mean: 0.47 days, 95% CI 0.133-0.811), higher hospital costs (adjusted mean: $3205.04, 95% CI 373.144-$6036.941, p= 0.027) and were less likely to be discharged to sites other than home (aOR: 0.81, 95% CI 0.70-0.95).
Conclusions: Hospitalized morbidly obese patients have lower rates of minor foot amputations compared to those without morbid obesity. However, they had similar rates of major amputations and a trend towards higher inpatient mortality. Concern for peri-operative complications may explain why morbidly obese patients have lower minor amputation rates. Future research should seek to identify contributors to reduced minor amputations in morbidly obese patients and how long-term outcomes may be impacted.