The Role of Diabetes Diagnosis and Treatment Status Beyond HbA1c Alone in Predicting Early Complications After Surgical Fixation of Ankle Fractures

BACKGROUND: Diabetes mellitus (DM) is a well-established risk factor for complications after surgical fixation of ankle fractures. Elevated hemoglobin A1c (HbA1c) has been associated with worse outcomes; however, it remains unclear whether HbA1c alone predicts perioperative risk independent of a formal DM diagnosis and treatment status. This study evaluated whether elevated preoperative HbA1c (≥8.0%) in patients without a documented diagnosis or pharmacologic treatment of DM is associated with increased early postoperative complications compared with patients with established DM. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database (2021 to 2024) was queried for patients undergoing open reduction and internal fixation of ankle fractures. Patients were stratified into four cohorts based on diabetes diagnosis/treatment status and glycemic control: (1) undiagnosed/untreated, HbA1c < 8.0%; (2) undiagnosed/untreated, HbA1c ≥ 8.0%; (3) diagnosed/treated, HbA1c < 8.0%; and (4) diagnosed/treated, HbA1c ≥ 8.0%. Propensity score matching (1:1) on age and sex yielded 388 matched patients (n = 97 per group). Primary outcomes were 30-day mortality, readmission, and revision surgery. Secondary outcomes included surgical site infection, organ-space infection, and medical complications. Multivariable logistic regression adjusted for residual differences in body mass index and comorbidities. RESULTS: Thirty-day mortality was rare (0.8%) and did not differ between groups (P = 0.381). Significant differences were observed in revision surgery (P = 0.006), superficial surgical site infection (P = 0.003), and organ space infection (P = 0.019). Patients with diagnosed/treated uncontrolled DM had higher odds of these complications compared with those with elevated HbA1c but no documented DM diagnosis or treatment (undiagnosed/untreated uncontrolled) (all P < 0.05). CONCLUSION: Patients with poorly controlled established diabetes had higher rates of early postoperative complications after ankle fracture open reduction and internal fixation compared with those with elevated HbA1c but no earlier diabetes diagnosis or treatment. Assessment of the presence and treatment status of diabetes may provide more meaningful perioperative risk stratification than HbA1c level alone. LEVEL OF EVIDENCE: Level III, retrospective cohort study.