Factors Associated with Relapse of Type 2 Diabetes Mellitus after Laparoscopic Sleeve Gastrectomy in Japanese Subjects: A Subgroup Analysis of J-SMART Study

INTRODUCTION: Laparoscopic sleeve gastrectomy (LSG) for morbidly obese patients often results in remission of type 2 diabetes (T2DM), but diabetes relapses in some of those patients. The frequency of T2DM relapse in Asians and the factors involved have not been adequately investigated. METHODS: The J-SMART study was conducted on 322 Japanese subjects with body mass index (BMI) ≥32 kg/m² who underwent LSG at 10 accredited centers in Japan between 2011 and 2014. Of these, 82 T2DM subjects with diabetes in complete or partial remission at 1 year after LSG and followed postoperatively for 5 years were included in the subgroup analysis and classified into two groups: diabetes remission-maintained and diabetes relapse. RESULTS: The mean age of all included subjects was 49.2 years, median BMI was 41.5 kg/m², and median HbA1c was 6.7%. Compared with the diabetes remission-maintained group, the diabetes relapse group at 5 years after LSG had significantly higher preoperative HbA1c, number of antidiabetic medications, and high-density lipoprotein cholesterol level; and lower BMI and homeostasis model assessment-beta cell function (HOMA-β). As many as 83.0% of the subjects were able to achieve HbA1c <7% at 5 years after LSG, but 26.8% of the subjects had diabetes relapse. Preoperative HbA1c significantly contributed to diabetes relapse (odds ratio 1.54, p = 0.049). In addition, the diabetes relapse group tended to have lower percentage total weight loss (%TWL) at 1 year after LSG and higher percentage weight regain (%WR) from postoperative nadir weight, compared with the diabetes remission-maintained group. The hazard ratio for diabetes relapse was 3.14-fold higher in subjects with %TWL ≥20% and %WR ≥25%, and 5.46-fold higher in those with %TWL <20% and %WR ≥25%, compared with %TWL ≥20% and %WR <25%. CONCLUSION: While LSG provides a high remission rate for T2DM, relapse is not uncommon. Preoperative HbA1c, poor weight loss, and excess weight regain after LSG contribute to diabetes relapse, suggesting the importance of treatment strategies focusing on these factors.