Haemoglobin A1c as a predictor of postoperative hyperglycaemia and complications after major colorectal surgery.

Background: Hyperglycaemia following major surgery increases morbidity, but may be improved by use of enhanced-recovery protocols. It is not known whether preoperative haemoglobin (Hb) A1c could predict hyperglycaemia and/or adverse outcome after colorectal surgery.

Methods: Some 120 patients without known diabetes underwent major colorectal surgery within an enhanced-recovery protocol. HbA1c was measured at admission and 4 weeks after surgery. All patients received an oral diet beginning 4 h after operation. Plasma glucose was monitored five times daily. Patients were stratified according to preoperative levels of HbA1c (within normal range of 4.5-6.0 per cent, or higher).

Results: Thirty-one patients (25.8 per cent) had a preoperative HbA1c level over 6.0 per cent. These had higher mean(s.d.) postoperative glucose (9.3(1.5) versus 8.0(1.5) mmol/l; P < 0.001) and C-reactive protein (137(65) versus 101(52) mg/l; P = 0.008) levels than patients with a normal HbA1c level. Postoperative complications were more common in patients with a high HbA1c level (odds ratio 2.9 (95 per cent confidence interval 1.1 to 7.9)).

Conclusion: Postoperative hyperglycaemia is common among patients with no history of diabetes, even within an enhanced-recovery protocol. Preoperative measurement of HbA1c may identify patients at higher risk of poor glycaemic control and postoperative complications.