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– In a retrospective cohort of 282,131 general surgery patients, 36% had diagnosed diabetes and 6.4% had HbA1c in the diabetes range without a prior diagnosis.
– Higher preoperative HbA1c was independently associated with progressively increased odds of 30‑day postoperative complications, with HbA1c >9.0% conferring the greatest risk (OR 1.32; 95% CI, 1.25–1.39) in patients with known diabetes.
– Undiagnosed diabetes (HbA1c >6.4% without a diagnosis) was associated with higher medical complications (OR 1.11; 95% CI, 1.04–1.18) and mortality (OR 1.24; 95% CI, 1.07–1.42).
– The findings support consideration of routine preoperative HbA1c screening and tailored perioperative glycemic management to improve risk assessment and outcomes.
