Physical Activity in Obese Type 2 Diabetes After Gastric Bypass or Medical Management

Abstract

Background: The purpose of this study was to compare effects of Roux-en-Y gastric bypass versus a multidisciplinary, group-based medical diabetes and weight management program on physical fitness and behaviors.

Methods: Physical behavior and fitness were assessed in participants of the study Surgery or Lifestyle With Intensive Medical Management in the Treatment of Type 2 Diabetes (SLIMM-T2D) (NCT01073020), a randomized, parallel-group trial conducted at a US academic hospital and diabetes clinic with 18- to 24-month follow-up. Thirty-eight type 2 diabetes patients with hemoglobin A1c ≥6.5% and body mass index 30-42 kg/m2 were randomized to Roux-en-Y gastric bypass or the medical program. A 6-minute walk test to evaluate fitness, self-reported physical activity, standardized physical surveys, and cardiometabolic risk assessment were performed at baseline and after intervention.

Results: Both groups similarly improved 6-minute walk test distance, with greater improvements in oxygen saturation and reduced heart rate after surgery. Self-reported physical activity improved similarly at 18-24 months after interventions, although exercise increased gradually after surgery, whereas early substantial increases in the medical group were not fully sustained. Self-reported total and physical health were similar by Short Form-36 but improved more in the Impact of Weight on Quality of Life survey after surgery. Improvement in cardiovascular risk scores, HbA1c, and body mass index were greater after surgery.

Conclusion: In this small, randomized study, both interventions led to therapeutic lifestyle changes and improved objective and self-reported physical fitness. Greater improvements in heart rate, oxygen saturation, and perceived impact of weight on health were seen after surgery, which could be attributable to greater weight loss. The clinical importance of these improvements with greater weight loss warrants further investigation.

Keywords: Bariatric surgery; Obesity; Physical activity; Physical fitness; Roux-en-Y gastric bypass; Type 2 diabetes.

Copyright © 2016 Elsevier Inc. All rights reserved.

Figures

Figure 1. Enrollment, Randomization, and Retention of the Study Participants

Consort diagram detailing enrollment, randomization, and retention of participants. All participants randomized and initiating intervention in the primary trial were eligible for the ancillary investigation on physical activity in this report. Abbreviations used in reasons for exclusion after screening: LAGB indicates laparoscopic adjustable gastric band; HbA1c, hemoglobin A1c; BMI, body mass index; GAD, antiglutamic acid decarboxylase antibody-positive.

Figure 2. Changes in Six Minute Walk Test and Self-Reported Exercise Measures

(A) Six Minute Walk Test – Distance. Difference in walking distance in meters, (B) Six Minute Walk Test – Oxygen Saturation. Change in oxygen saturation (SpO2, %), and (C) Six Minute Walk Test – Heart Rate. Change in heart rate in beats per minute, immediately after 6-minute walk test and (D) Self-Reported Exercise. Self-reported exercise in minutes per week, at early, 12-month, 18-month, and 24-month time points compared between patients participating in the intensive medical and weight management or undergoing RYGB surgery. Note: “Early” time point is defined in “Trial Design, Randomization, and Intervention” section as after participants lost 10% of their baseline weight or at the 3-month mark, whichever occurred first. Mean and standard error are shown. (●) Roux-en-Y gastric bypass (RYGB), (○) Intensive medical weight management (IMWM), (X) Last observation carried forwards (LOCF) for RYGB group, (◇) Last observation carried forwards (LOCF) for IMWM group. Abbreviations: beats per minute (BPM), meters (m), minutes per week (min/week). P-values represent the difference between groups over 24 months in mixed model analysis.

Figure 3. Association Between Weight Change and Improvement in Measures of Cardiorespiratory Fitness

(A) Weight Change vs. Oxygen Saturation. Association between change in weight and change in oxygen saturation immediately following six-minute walk test between 18 and 24 months from intervention in both groups. (B) Weight Change vs. Heart Rate. Association between change in weight and heart rate immediately following six-minute walk test between 18 and 24 months from intervention in both study groups. (●) Roux-en-Y gastric bypass (RYGB), (○) Intensive medical weight management (IMWM), (●) Overlapping data from two participants, one from RYGB, one from IMWM.

Figure 4. Patient Reported Outcomes of Physical Health

Change in patient-reported impact of weight on quality of life (IWQOL) and Short Form-36 (SF-36) total scores and physical function domains over time in Roux-en-Y gastric bypass (RYGB) and intensive medical weight management (IMWM) groups. (A) IWQOL total score and (B) IWQOL physical functioning subscale, and (C) SF-36 total score and (D) SF-36 physical function subscale at early, 12-month, 18-month, and 24-month time points in both study groups. Note: “Early” time point is defined in “Trial Design, Randomization, and Intervention” section as after participants lost 10% of their baseline weight or at the 3 month mark, whichever occurred first. Mean and standard error are shown. (●) Roux-en-Y gastric bypass (RYGB), (○) Intensive medical weight management (IMWM), (X) Last observation carried forwards (LOCF) for RYGB group, (◇) Last observation carried forwards (LOCF) for IMWM group. P-values represent the difference between groups over 24 months in mixed model analysis.

Figure 5. Cardiometabolic Changes Following RYGB and Intensive Medical Weight Management

(A) Change in Hemoglobin A1c and (B) Body Mass Index at early, 12-month, 18-month, and 24-month time points in patients randomized to RYGB or the intensive medical and weight management program. Note: “Early” time point is defined in “Trial Design, Randomization, and Intervention” section as after participants lost 10% of their baseline weight or at the 3 month mark, whichever occurred first. Mean and standard error are shown. (●) Roux-en-Y gastric bypass (RYGB), (○) Intensive medical weight management (IMWM), (X) Last observation carried forwards (LOCF) for RYGB group, (◇) Last observation carried forwards (LOCF) for IMWM group. P-values represent the difference between groups over 24 months in mixed model analysis. (C) UKPDS Risk Scores at 18–24 months in the two study cohorts. Baseline scores are indicated in the table at top, and change scores (baseline to 18–24 months) in the bar graphs below. P-values indicate differences in change scores between groups.