Background: Roux-en-Y gastric bypass (RYGBP) and sleeve gastrectomy (SG) have been associated with a high remission rate of type 2 diabetes mellitus (T2DM). However, whether such remission is associated with full restoration of postprandial glucose profile and/or the potentially nonrestored glycemic profile is associated with altered beta cell function, and relapse of T2DM over time is unknown.
Methods: Cross-sectional studies comparing (1) glucose and proinsulin/insulin response to a standardized liquid mixed meal (SLMM) challenge (n = 31), (2) glucose response in normal living conditions assessed using continuous glucose monitoring (CGM) (n = 16), and prospective observational study comparing (3) rates of relapse of T2DM after surgery (n = 232) in subjects with remission of T2DM ensuing RYGBP or SG.
Results: In RYGB individuals, SLMM elicited faster and sharper rise in plasma glucose compared with SG, with 88.2% and 42.9% of the study subjects presenting respectively a peak glucose more than 180 mg/dL (all, P < 0.05). During CGM, average percent time in hyperglycemic and hypoglycemic range was larger in RYGBP (respectively, 4.6% and 12.7%) compared with SG subjects (respectively, 0.4% and 3.2%; both P < 0.05). However, (1) no differences were found in fasting or stimulated proinsulin/insulin ratio, and (2) higher rates of T2DM relapse were observed after SG (hazard ratio: 2.339; P = 0.034).
Conclusions: Remission of T2DM after RYGBP and SG is associated with distinct glycemic profiles. However, longer time spent in hyperglycemia and in hypoglycemia after RYGBP compared with SG is not associated with persistence of altered beta cell function or higher rates of relapse of T2DM over time.