Associations Between Preoperative Glucose and Hemoglobin A1c Level and Myocardial Injury After Noncardiac Surgery

Background Perioperative blood glucose level has shown an association with postoperative outcomes. We compared the incidences of myocardial injury after noncardiac surgery (MINS) and 30‐day mortality, according to preoperative blood glucose and hemoglobin A1c (HbA1c) levels. Methods and Results The patients were divided according to blood glucose level within 1 day before surgery. The hyperglycemia group was defined with fasting glucose >140 mg/dL or random glucose >180 mg/dL. In addition, we compared the outcomes according to HbA1c >6.5% among patients with available HbA1c within 3 months before surgery. The primary outcome was MINS, and 30‐day mortality was also compared. A total of 12 304 patients were enrolled and divided into 2 groups: 8324 (67.7%) in the normal group and 3980 (32.3%) in the hyperglycemia group. After adjustment with inverse probability of weighting, the hyperglycemia group exhibited significantly higher incidences of MINS and 30‐day mortality (18.7% versus 27.6%; odds ratio, 1.29; 95% CI, 1.18–1.42; P <0.001; and 2.0% versus 5.1%; hazard ratio, 2.00; 95% CI, 1.61–2.49; P <0.001, respectively). In contrast to blood glucose, HbA1c was not associated with MINS or 30‐day mortality. Conclusions Preoperative hyperglycemia was associated with MINS and 30‐day mortality, whereas HbA1c was not. Immediate glucose control may be more crucial than long‐term glucose control in patients undergoing noncardiac surgery. Registration URL: https://www.cris.nih.go.kr ; Unique identifier: KCT0004244.