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 HbA1c 8.5 ± 1.3% [69 ± 14 mmol/mol]) to laparoscopic RYGB (n = 19) or IMWM (n = 19). Changes in weight, HbA1c, 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 HbA1c (-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 HbA1c 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 HbA1c, reduced cardiovascular risk, and improvements in obesity-related quality of life in obese patients with type 2 diabetes.

Trial registration: ClinicalTrials.gov NCT01073020.

© 2018 by the American Diabetes Association.

Figures

Figure 1

Changes (±SEM) in BMI (A), HbA1c (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 HbA1c 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, HbA1c, IWQOL, and PAID) was associated with improved quality of life.