Preoperative insulin therapy as a marker for type 2 diabetes remission in obese patients after bariatric surgery

Abstract

BackgroundObesity not only increases the chances of developing diabetes—one of the top causes of death in the United States—but it also results in further medical complications. ObjectiveTo compare the 6-month and 1-year postoperative remission rates of type 2 diabetic (T2D) patients after bariatric surgery based on preoperative glycosylated hemoglobin (A1C) stratification and pharmacologic therapy: insulin-dependent diabetic (IDD) versus noninsulin-dependent diabetic (NIDD). SettingAcademic hospital, United States. MethodsWe retrospectively analyzed a prospectively maintained database of 186 obese patients with a diagnosis T2D who had undergone either a sleeve gastrectomy or a Roux-en-Y gastric bypass surgery at our hospital. ResultsAt 6 months (n = 180), patients who were stratified by preoperative A1C levels (<6.5; ≥6.5 to<8; ≥8) had 70.5%, 51.7%, and 30.0% remission rates (P<.001) and at 1 year (n = 118) patients had 72.0%, 54.0%, and 42.8% remission rates (P = .053), respectively. When patients were substratified by preoperative pharmacologic therapy, IDD and NIDD patients had different remission rates within the same A1C level. At 6-months follow-up within A1C ≥6.5 to<8 (IDD versus NIDD), the remission rate was 23.5% versus 64.1% (odds ratio [OR]: .173, confidence interval [CI]: .0471, .6308, P = .0079), and within A1C ≥8 the remission was 24.0% versus 37.5% (OR: .5263, CI: .2115, 1.3096, P = .1676), respectively. At 1-year follow-up within A1C ≥6.5 to<8, the remission rate was 30.0% versus 62.9% (OR: .2521, CI: .0529, 1.2019, P = .0838), and within A1C ≥8 the remission was 31.4% versus 61.9% (OR: .2821, CI: .0908, .8762, P = .0286), respectively. Furthermore, when IDD patients were compared between A1C ≥6.5 to<8 and A1C ≥8 the remission rates were nearly identical, and for NIDD patients A1C was not significantly associated with remission regardless of the level, except at 6 months. ConclusionWhile a difference was observed between overall A1C levels—the lower the A1C level, the higher the remission rate—IDD patients had lower remission rates than NIDD patients irrespective of A1C levels; further, IDD patients performed similarly across A1C levels.