This study examined whether elevated A1C in patients with diabetes is associated with a higher incidence of postoperative infections and other complications. Researchers followed 50 noncardiac surgical patients for 7 postoperative days. Half of the patients had an A1C <7% and the other half had an A1C ≥7%. The two groups were otherwise comparable except that the higher-A1C group had significantly higher pre-induction and postoperative blood glucose levels, with wider variability in the first 24 hours after surgery. During the first postoperative week, 11 patients developed complications, of whom 10 were in the higher-A1C group. Elevated A1C, unlike a single preoperative blood glucose value, may predict difficult postoperative glucose control and postsurgical complications.