Bariatric surgery is more strongly recommended in obese patients with type 2 diabetes mellitus when diabetes is inadequately controlled despite optimal lifestyle and pharmacologic therapy, including insulin. With the increase of bariatric surgery procedures across the world, it is important to better understand the outcome of the disease, especially in surgical candidates experiencing advanced stages of T2D.
However, data on the midterm effect of Roux-en-Y gastric bypass and sleeve gastrectomy in this group of patients is scant.
We review a study that was conducted at Hospital Clinic (Barcelona) to evaluate the extent and duration of the hypoglycemic effect of bariatric surgery on patients with type 2 diabetes mellitus treated with insulin.
A prospective observational study (4.9 ± 1.9 years) was conducted on the results of TDM2, the changes in hemoglobin A1C (HbA1c) and the therapy of diabetes in individuals with DM2 treated with insulin who underwent Roux-en-Y gastric bypass (24 patients) or sleeve gastrectomy (50 patients).
Study participants were selected from among the 344 patients with T2DM who underwent BS at Hospital Clinic between January 2005 and December 2013. Selection criteria for the study included insulin therapy before surgery and postsurgical follow-up of at least 24 months at the time of this analysis.
T2DM remission was defined as HbA1c < 6.5% and FPG < 126 mg/dL without hypoglycemic medication. T2DM relapse criteria for T2DM according to ADA after T2DM remission attained after bariatric surgery.
Overall, remission was observed initially in 20 out of 74 patients (27%). However, throughout follow-up T2D relapse was observed in 13 of 20 participants (65%), resulting in a final proportion of 90.5% of the cohort presenting with T2DM at their last follow-up visit (67 of 74 patients).
Sustained remission was associated with younger age, lower HbA1C, a tendency toward shorter duration of T2DM, and N-BB insulin therapy compared with patients with nonremitting diabetes but not with differences in %EWL over the observation period
Initial reduction of HbA1C and high rates of insulin cessation were observed (HbA1c nadir 5.9% ± 0.9%, insulin cessation rate 66.2%). However, these were followed by progressive deterioration of HbA1c (HbA1c at last follow-up 7.4% ± 1.3%; P < .001) and need for insulin therapy reintroduction (rate of insulin cessation at last follow-up visit 54%; P=.04).
In multivariate analysis, larger maximum percent excess weight loss and nonbasal bolus insulin therapy were identified as significant predictors of diabetes remission, insulin cessation, and durability of HbA1C <7%.
Comparison of T2DM remission rates at 1, 2, and 3 years demonstrated a tendency toward higher remission rates after RYGB, even though comparison was significant only at 3 years.
Likewise, RYGB patients presented with lower HbA1c levels at 24, 36, and 48 months after surgery despite % excess of weight loss not being significantly different between surgical groups.
Finally, the Kaplan-Meir analysis demonstrated that the median time free of T2D was longer for RYGB patients than for SG patients (47.8 ± 14.6 and 28.8 ± 4.6 mo, respectively), albeit no statistically significant differences were found (P = 0.167)
In insulin-treated patients with T2DM, bariatric surgery is associated with a low likelihood of midterm diabetes remission.
Overall, in this group of patients, the marked initial improvement in glycemic control and insulin independence are of limited durability.
In addition, in this group of patients, the need for prandial insulin and lower postsurgical weight loss may hamper the beneficial effects of bariatric surgery on glycemic control.