van den Boom W, et al. - This study was performed to evaluate the association of preoperative hemoglobin A_1c (A1C) with perioperative glucose control and their relationship with 30-day mortality. A1C was found to be positively correlated with perioperative glucose, however, it was not associated with increased 30-day mortality after controlling for glucose. Perioperative glucose predicted 30-day mortality, linearly in noncardiac and nonlinearly in cardiac procedures. This finding affirmed that perioperative glucose control was connected with surgical outcomes. Nevertheless, A1C, reflecting antecedent glycemia, proved to be a less useful predictor.