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.
Keywords: blood glucose level; hemoglobin A1c; myocardial injury; noncardiac surgery.