Preoperative glycosylated haemoglobin as a predictor of postoperative analgesic requirements in diabetic patients: A prospective observational study.

Abstract

In diabetic individuals undergoing surgery, the analgesic effect of opioids on postoperative pain may be different from normal. Although the ability of glycosylated haemoglobin (HbA1c) to predict adverse events and outcomes after major surgery has recently been assessed, the ability of HbA1c to predict the need for postoperative analgesia has not been determined. The objective of this study is to evaluate the relationship between preoperative glycaemic control in diabetic individuals and the opioid requirement for postoperative pain treatment. A prospective observational study. Single university hospital. Fifty-two diabetic patients undergoing open nephrectomy surgery. To evaluate the effect of long-term glucose control on postoperative analgesia requirements, the patients were divided into those with good glycaemic control (HbA1c <6.5%) and those with poor glycaemic control (HbA1c ≥6.5%). The amount of postoperative opioid received, the pain scores and satisfaction with analgesia were compared between these two groups. The two groups were compared using univariate and multivariate analyses to investigate possible independent predictors of postoperative analgesic opioid consumption. The total fentanyl consumption during the first 48 h after surgery was 20% higher in the HbA1c at least 6.5% group than in the HbA1c less than 6.5% group (P = 0.007). Compared with the HbA1c less than 6.5% group, there was a higher proportion of patients with inadequate analgesia during the early postoperative period (89.3 vs. 66.7% on moving; 71.4 vs. 37.5% while resting, P < 0.05) and lower satisfaction with analgesia (3.4 ± 1.0 vs. 4.1 ± 1.0) on a 5-point Likert Scale (P = 0.008) in the HbA1c at least 6.5% group. Univariate analysis revealed a significant correlation between preoperative HbA1c level and postoperative fentanyl requirements during the first 48 h after surgery (r = 0.455, P = 0.001). Using a multivariate analysis, independent predictors of postoperative fentanyl requirement were HbA1c and weight (adjusted R = 0.274). This study demonstrated that in diabetic patients, the preoperative level of HbA1c was associated with the postoperative fentanyl consumption. In diabetic patients, the HbA1c level prior to surgery may be useful in anticipating postoperative analgesic requirements and help to improve patient counselling regarding postoperative pain.