The Association of Perioperative Glycemic Control With Postoperative Surgical Site Infection Following Open Carpal Tunnel Release in Patients With Diabetes.

BACKGROUND: The primary goal of the study was to evaluate the association of hemoglobin A1c (HbA1c) levels in diabetic patients with the incidence of surgical site infection (SSI) following open carpal tunnel release (CTR). Our secondary objective was to calculate an HbA1c level in diabetic patients that predicted SSI after open CTR.

METHODS: A national private-payer insurance database was queried for patients who underwent open CTR using Current Procedural Terminology (CPT) code 64721. Patients who underwent concomitant procedures were excluded. Diabetic patients who had their HbA1c level checked within 3 months of surgery were stratified into 6 mutually exclusive groups based on HbA1c levels in 1.0 mg/dL increments from <6.0 to >10 mg/dL. The incidence of SSI was determined for each group by either a diagnosis or procedure for SSI within 1 year using CPT and International Classification of Diseases, 9th Revision (ICD-9) codes. A receiver operating characteristic (ROC) analysis was performed to determine an HbA1c level above which the risk of postoperative SSI was significantly increased.

RESULTS: 7958 diabetic patients who underwent open CTR and had an HbA1c recorded within 3 months of surgery were assessed. The incidence of SSI within 1 year was associated with HbA1c levels. The inflection point of the ROC curve corresponded to an HbA1c level between 7 and 8 mg/dL.

CONCLUSIONS: Increased HbA1c levels are associated with increased SSI rates in diabetic patients undergoing open CTR. A perioperative HbA1c between 7 and 8 mg/dL could serve as a threshold for an increased risk of SSI following open CTR.