Role of Chronic Glycemic Status and Perioperative Hyperglycemia in Postoperative Morbidity After Free Flap Reconstruction

 

Diwakar Phuyal, MBBS; Bianca Di Charo, MD; Sara Yacoub, MPH; Antonio Rampazzo, MD, PhD; Bahar Bassiri Gharb, MD, PhD

 

Introduction: Diabetes is a recognized risk factor for impaired wound healing and infection, yet the relative impact of chronic glycemic status (HbA1c) and perioperative hyperglycemia on outcomes after free flap reconstruction remains unclear. This study evaluated the independent associations between diabetes status, perioperative glucose, and HbA1c with postoperative morbidity.

 

Methods: A retrospective cohort study was conducted using the TriNetX Research Network, including U.S. patients undergoing free flap reconstruction (2005–2025). Patients were stratified by diabetes status, perioperative glucose (<180 vs. ≥180 mg/dL), and HbA1c (<7% vs. ≥7%). Propensity score matching (1:1) was applied to balance demographics, comorbidities, and flap type. Primary outcomes were 60-day overall, major, and minor complications; secondary outcomes included wound complications, systemic events, reoperations, and unplanned healthcare utilization. Relative risks (RR) with 95% confidence intervals (CI) were calculated.

 

Results: Of 41,705 patients, 8,537 had diabetes. After matching (n=8,404/group), diabetes was associated with higher overall (51.6% vs. 49.5%, RR 1.04, CI 1.01–1.08, p=0.008) and major complications (18.9% vs. 16.9%, RR 1.12, p=0.0012). Perioperative hyperglycemia (≥180 mg/dL) was associated with higher overall (RR 1.14, p<0.0001), major (RR 1.12, p=0.001), and minor complications (RR 1.14, p<0.0001), as well as increased wound dehiscence, superficial surgical site infection, sepsis, and incision and drainage. HbA1c ≥7% did not predict overall complications but was associated with higher skin graft failure (RR 2.08, p=0.02).

 

Conclusions: Perioperative hyperglycemia is a strong predictor of morbidity after free flap reconstruction. Routine glucose monitoring and maintaining perioperative glucose <180 mg/dL may reduce wound complications, infection, and reoperations.