Is There a Correlation Between Preoperative HbA1c Change, Long-Term Weight Loss and Glycaemic Control in Patients With Type 2 Diabetes Undergoing Metabolic Surgery?

Abstract

Introduction Optimisation of patients with type 2 diabetes mellitus (T2DM) prior to metabolic surgery aims to achieve tight glycaemic control by the time of surgery. Little is known about the influence of altering preoperative glycated haemoglobin (HbA1c) on postoperative weight loss and glycaemic control. The aim of this study was to determine whether a change in HbA1c during the preoperative period correlated with long-term weight maintenance and HbA1c in patients undergoing metabolic surgery. The quantity of glucose-lowering medication used prior to and following surgery was also examined. Methods A retrospective analysis was conducted on patients with T2DM who underwent metabolic surgery between 2013 and 2017. Preoperative HbA1c change was measured as a change in glycaemic control during the one-year pre-surgery. The primary outcomes were % excess weight loss (EWL) and HbA1c at five-year post-surgery. Secondary outcomes were % EWL and HbA1c at one-year post-surgery and the use of glucose-lowering medications post-surgery. The Pearson correlation coefficient (r) was used to determine the relationship between the pre-surgery HbA1c change and postoperative % EWL and HbA1c. A chi-squared test was used to calculate the statistical impact of changes in medication use post-surgery. Results Sixty-nine patients with complete data were included in the study. The mean change in HbA1cin the one-year pre-surgery, the one-year post-surgery and five-year post-surgery was -0.9% (1.5), -0.7% (1.2) and 0% (0 1.8), respectively. A change in HbA1cin the one-year pre-surgery did not correlate with % EWL at one-year and five-year post-surgery or with HbA1cat one-year and five-year post-surgery. At one-year and five-year post-surgery, there was a significant decrease in the proportion of patients requiring glucose-lowering medications compared to patient use prior to surgery (p < 0.001). Conclusion This study demonstrated a significant reduction in the proportion of glucose-lowering medication required long-term following metabolic surgery. Altering preoperative glycaemic control was not associated with long-term weight maintenance or glycaemic control.

Keywords: glycaemic control; long-term weight loss; metabolic surgery; obesity; type 2 diabetes.