Preoperative glycated hemoglobin as a predictor of infection in patients undergoing spinal surgery: A retrospective analysis of MIMIC-IV database

Objective To investigate whether elevated preoperative glycated hemoglobin (HbA1c) levels predict postoperative infections and related clinical outcomes following spinal surgery. Design Retrospective cohort analysis utilizing the publicly available MIMIC-IV database. Setting Single-center academic medical institution with intensive care capability. Patients A total of 246 adult patients undergoing spinal surgery with recorded preoperative HbA1c levels. Interventions None. Measurements The primary outcome was clinician-suspected postoperative infection within 24 h after surgery, defined by culture orders plus antibiotic initiation. Secondary outcomes included Sepsis-3 criteria-defined sepsis, SIRS sepsis, septic shock, and hospital length of stay. Main results Elevated preoperative HbA1c (≥6.5 %) was independently associated with significantly increased odds of clinician-suspected postoperative infection (OR 3.20; 95 % CI 1.22–8.36; p  = 0.018), after controlling for comorbidity burden and surgical complexity. However, elevated HbA1c did not independently predict more severe outcomes such as Sepsis-3 sepsis or septic shock. Conclusions Elevated preoperative HbA1c substantially increases the likelihood of early clinician suspicion and empirical treatment of postoperative infections after spinal surgery. Routine HbA1c screening should therefore be considered during preoperative evaluations, especially for elective instrumented spinal procedures known for higher infection risks. While these findings support existing clinical guidelines recommending perioperative glycemic optimization, elevated HbA1c alone may not predict severe infection or septic complications once comorbidity burden is considered