Clinical and Patient-Centered Outcomes in Obese Patients With Type 2 Diabetes 3 Years After Randomization to Roux-en-Y Gastric Bypass Surgery Versus Intensive Lifestyle Management: The SLIMM-T2D Study

Abstract

Objective: To compare the effect of Roux-en-Y gastric bypass (RYGB) surgery versus intensive medical diabetes and weight management (IMWM) on clinical and patient-reported outcomes in obese patients with type 2 diabetes.

Research design and methods: We prospectively randomized 38 obese patients with type 2 diabetes (15 male and 23 female, with mean ± SD weight 104 ± 16 kg, BMI 36.3 ± 3.4 kg/m², age 52 ± 6 years, and HbA_1c 8.5 ± 1.3% [69 ± 14 mmol/mol]) to laparoscopic RYGB (n = 19) or IMWM (n = 19). Changes in weight, HbA_1c, cardiovascular risk factors (UKPDS risk engine), and self-reported health status (the 36-Item Short-Form [SF-36] survey, Impact of Weight on Quality of Life [IWQOL] instrument, and Problem Areas in Diabetes Survey [PAID]) were assessed.

Results: After 3 years, the RYGB group had greater weight loss (mean -24.9 kg [95% CI -29.5, -20.4] vs. -5.2 [-10.3, -0.2]; P < 0.001) and lowering of HbA_1c (-1.79% [-2.38, -1.20] vs. -0.39% [-1.06, 0.28] [-19.6 mmol/mol {95% CI -26.0, -13.1} vs. -4.3 {-11.6, 3.1}]; P < 0.001) compared with the IMWM group. Changes in cardiometabolic risk for coronary heart disease and stroke were all more favorable in RYGB versus IMWM (P < 0.05 to P < 0.01). IWQOL improved more after RYGB (P < 0.001), primarily due to subscales of physical function, self-esteem, and work performance. SF-36 and PAID scores improved in both groups, with no difference between treatments. A structural equation model demonstrated that improvement in overall quality of life was more strongly associated with weight loss than with improved HbA_1c and was manifest by greater improvements in IWQOL than with either SF-36 or PAID.

Conclusions: Three years after randomization to RYGB versus IMWM, surgery produced greater weight loss, lower HbA_1c, reduced cardiovascular risk, and improvements in obesity-related quality of life in obese patients with type 2 diabetes.

Trial registration: ClinicalTrials.gov NCT01073020.

Figure 1

Changes (±SEM) in BMI (A), HbA_1c (B), and antidiabetes (C), antihypertensive (D), and lipid-lowering (E) medications over 36 months in obese patients with type 2 diabetes randomized to RYGB (open squares with dashed lines) versus IMWM (filled circles with solid lines). P values represent overall differences between treatment groups by linear mixed-effects models adjusted for baseline values. ^atime × group interaction also significant at P < 0.05. *P < 0.05, **P < 0.01, ***P < 0.001 vs. baseline. †P < 0.05, ††P < 0.01, †††P < 0.001 between groups. DM Meds, antidiabetes medications; BP Meds, antihypertensive medications; Lipid Meds, lipid-lowering medications.

Figure 2

Changes (±SEM) in SF-36 total score (SF-36 Total) (A), SF-36 physical (B), SF-36 mental (C), PAID (D), and IWQOL total score (E), and subscales of physical function (F), self-esteem (G), sex life (H), public distress (I), and work performance (J) over 36 months in obese patients with type 2 diabetes randomized to RYGB (open squares with dashed lines) versus IMWM (filled circles with solid lines). In A–C, an increase in score indicates improvement (better health status). In D–J, a decrease in score indicates improvement (fewer problems with diabetes or less impact of weight on quality of life). P values represent overall differences between treatment groups by linear mixed-effects model adjusted for baseline values. ^atime × group interaction also significant at P < 0.05. ^btime × group interaction significant at P < 0.05 but group effect not significant. *P < 0.05, **P < 0.01, ***P < 0.001 vs. baseline. †P < 0.05, ††P < 0.01, †††P < 0.001 between groups.

Figure 2

Changes (±SEM) in SF-36 total score (SF-36 Total) (A), SF-36 physical (B), SF-36 mental (C), PAID (D), and IWQOL total score (E), and subscales of physical function (F), self-esteem (G), sex life (H), public distress (I), and work performance (J) over 36 months in obese patients with type 2 diabetes randomized to RYGB (open squares with dashed lines) versus IMWM (filled circles with solid lines). In A–C, an increase in score indicates improvement (better health status). In D–J, a decrease in score indicates improvement (fewer problems with diabetes or less impact of weight on quality of life). P values represent overall differences between treatment groups by linear mixed-effects model adjusted for baseline values. ^atime × group interaction also significant at P < 0.05. ^btime × group interaction significant at P < 0.05 but group effect not significant. *P < 0.05, **P < 0.01, ***P < 0.001 vs. baseline. †P < 0.05, ††P < 0.01, †††P < 0.001 between groups.

Figure 3

Structural equation model depicting the relationship between predictor variables (change in HbA_1c and change in weight) and the latent construct (change in quality of life [QOL]) from baseline to 1 year for all subjects in the study. Change in quality of life is measured by changes in patient responses to the IWQOL, PAID, and SF-36 instruments. Numbers represent standardized β-coefficients; ε1–ε4 represent error terms from the model. Negative β-coefficients indicate that a decrease in the measurement or score (weight, HbA_1c, IWQOL, and PAID) was associated with improved quality of life.