The Association of Perioperative Glycemic Control with Deep Postoperative Infection After Anterior Cervical Discectomy and Fusion in Patients with Diabetes.

OBJECTIVE: To evaluate the association of perioperative hemoglobin A1c (HbA1c) level in patients with diabetes with the incidence of infection after anterior cervical discectomy and fusion requiring operative intervention, in addition to determining if a threshold level of HbA1c above which the risk of infection increases significantly exists.

METHODS: A national administrative database was queried for patients who underwent primary anterior cervical discectomy and fusion with diabetes who had a perioperative HbA1c level recorded within 3 months of surgery. These patients were stratified based on their HbA1c level in 0.5-mg/dL increments from <5.49 mg/dL to >11.5 mg/dL. The incidence of infection requiring operative intervention within 1 year was then identified using Current Procedural Terminology and International Classification of Diseases, Ninth Revision codes. A receiver operating characteristic (ROC) analysis was performed to determine a threshold value of the HbA1c level.

RESULTS: A total of 3341 patients with a perioperative HbA1c level were included. The rate of deep infection requiring irrigation and debridement postoperatively stratified by HbA1c level ranged from a low of 1.5% to a high of 6.4% and was significantly correlated with increasing HbA1c levels (P = 0.005). The results of ROC analysis determined that the inflection point of the ROC curve corresponded to an HbA1c level higher than 7.5 mg/dL (P = 0.022; area under the curve, 0.67; specificity, 68%; sensitivity, 46%).

CONCLUSIONS: The risk of deep postoperative infection in patients with diabetes mellitus increases as the perioperative HbA1c level increases. ROC analysis determined that a perioperative HbA1c level higher than 7.5 mg/dL could serve as a threshold for a significantly increased risk of infection.