Association Between Diabetes, Obesity, and Short-Term Outcomes Among Patients Surgically Treated for Ankle Fracture

Although obesity is widely accepted as a risk factor for surgical complications following orthopaedic surgery, the literature is unclear with regard to the effect of obesity on outcomes of ankle fracture surgery, particularly in the setting of competing risks from diabetes. We hypothesized that obesity would be independently associated with more frequent complications, longer hospital length of stay, and higher costs of care among patients with and without diabetes.

With use of data from 2001 to 2010 from the Nationwide Inpatient Sample, we identified all adult patients who underwent surgical treatment for a primary diagnosis of an isolated ankle fracture or dislocation. We then divided patients into four groups according to the presence or absence of diabetes or obesity: Group A included patients with neither diagnosis; Group B, obesity alone; Group C, diabetes alone; and Group D, both diagnoses. Multivariable regression models were constructed to determine the association between diagnostic group and in-hospital complications, hospital length of stay, and imputed costs of care, while controlling for other conditions.

The final sample included 148,483 patients (78.4% in Group A, 5.0% in Group B, 13.6% in Group C, and 3.0% in Group D). The median age was 53.0 years, and most patients (62.2%) were female and had a closed bimalleolar or trimalleolar fracture (62.2%). In the unadjusted analysis, the frequency of in-hospital complications (2.6%, 4.2%, 5.3%, and 6.5% in Groups A, B, C, and D, respectively; p < 0.001), length of stay (3.0, 3.6, 4.4, and 4.8 days, respectively; p < 0.001), and costs of care ($9686, $10,555, $11,616, and $12,804, respectively, in 2010 U.S. dollars; p < 0.001) increased across groups. Patients with obesity alone (Group B) (adjusted odds ratio [OR] = 1.4; 95% confidence interval [CI] = 1.3 to 1.6), diabetes alone (Group C) (OR = 1.1; 95% CI = 1.0 to 1.2), and both diagnoses (Group D) (OR = 1.4; 95% CI = 1.2 to 1.5) had more frequent in-hospital complications than those with neither diagnosis.

We found that patients with concurrent diagnoses of diabetes and obesity had higher health-care utilization and costs than those with neither diagnosis or with obesity alone or diabetes alone. The delay in the diagnosis of diabetes may somewhat obscure the true effect.