BS SO14 - Is there a correlation between preoperative HbA1c changes and long-term weight loss plus glycemic control in patients with type 2 diabetes undergoing metabolic surgery?

Abstract Background Optimization of patients with type 2 diabetes mellitus (T2DM) prior to metabolic surgery aims to achieve tight glycemic control by the time of surgery. Little is known about the influence of altering preoperative HbA1c on postoperative weight loss and glycemic 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 proportion of glucose-lowering medication used following surgery was also examined. Method Retrospective analysis was conducted of patients with T2DM who underwent metabolic surgery between 2013 – 2017. Preoperative HbA1c change was measured as change in glycemic control during the 1-year pre-surgery. Primary outcomes were % excess weight loss (EWL) and HbA1c at 5 years post-surgery. Secondary outcomes were % EWL and HbA1c at 1-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. Chi-squared test was used to calculate the statistical impact of change in medication use post-surgery Results Sixty-nine patients with complete data were included in the study. The mean change in HbA1c in the 1-year pre-surgery, the 1-year post-surgery and 5-years post-surgery was -0.9% (± 1.5), -0.7% (± 1.2) and 0% (± 1.8), respectively. The change in HbA1c in the 1-year pre-surgery did not correlate with % EWL at 1-year and 5-years post-surgery or with HbA1c at 1-year and 5-years post-surgery. There was a significant decrease in the proportion of patients requiring glucose-lowering medications at 1-year and 5 years post-surgery (p<0.05). Conclusion This study demonstrated a significant reduction in the proportion of glucose-lowering medication required long-term following metabolic surgery. Altering pre-operative glycemic control was not associated with long term weight maintenance or glycemic control.