The clinical significance of an elevated postoperative glucose value in nondiabetic patients after colorectal surgery: evidence for the need for tight glucose control?

OBJECTIVES: To evaluate the significance of hyperglycemia in patients without a preoperative diagnosis of diabetes undergoing elective colorectal surgery.
METHODS: Preoperative and all postoperative blood glucose measurements were retrieved for 2628 consecutive patients undergoing elective colorectal resection within 2 years at 1 center. Nondiabetic patients were identified as those without a preoperative diagnosis of diabetes and/or based on HbA1C levels. The association between any elevated postoperative random glucose value (hyperglycemia: >125 mg/dL) and level of elevation (>125 mg/dL or >200 mg/dL) within 72 hours of surgery in nondiabetic patients with 30-day mortality and infectious and noninfectious complications was assessed.
RESULTS: Evaluation of 16,404 postoperative glucose measurements for all 2447 nondiabetic patients who underwent surgery in 2010 and 2011 revealed that 66.7% patients experienced hyperglycemia. Degree of hyperglycemia correlated with increasing American Society of Anesthesiologists class and surgical severity (blood loss). Hyperglycemia was associated with infectious and noninfectious complications and mortality, the rates of these complications increasing parallel to the degree of hyperglycemia. Hyperglycemia was independently associated with septic complications (P = 0.024).
CONCLUSIONS: Postoperative hyperglycemia is frequent after elective colorectal surgery in nondiabetic patients. Even a single postoperative elevated glucose value is adversely associated with morbidity and mortality; this risk is related to the degree of glucose elevation. These findings strongly support monitoring of glucose values and early consideration of management strategies for glycemic control after surgery even in nondiabetic patients.