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The Role of Bariatric Surgery in Prevention of Kidney Disease Progression in Moderately Obese Patients With Type 2 Diabetes

The Role of Bariatric Surgery in Prevention of Kidney Disease Progression in Moderately Obese... To the Editor We read with great interest the article by Cohen et al1 that compared the best medical treatment with gastric bypass for the remission of microalbuminuria in early-stage chronic kidney disease in patients with type 2 diabetes and obesity. Knowing the difficulties of carrying out a randomized clinical trial involving surgical procedures, the study flowchart and data analysis always arouse our interest. What sparked our attention in this study was the maintenance of 5 patients (9.8%) who were not operated on in the gastric bypass group performing an intention-to-treat (ITT) analysis. Outcomes at 24 months (Table 2) were presented with the inclusion of these patients, except for albumin and creatinine ratio and metabolic control, which were also presented with the sole inclusion of “complete cases.” The decision to proceed with an ITT, “modified” ITT, or per protocol analysis is often a challenge.2,3 In the landmark study of Schauer et al,4 only 1 of 100 patients assigned to surgical procedure did not undergo sleeve gastrectomy and was not included in the outcome analysis. It is well known that performing postrandomization exclusions may lead to biased estimation of the treatment effect. On the other hand, noncompliance with assigned therapy may mean that the intention-to-treat analysis underestimates the potential benefit of the treatment.5 In this study, performing the surgical procedure is fundamental to the definition of causality, and a considerable number of patients (9.8%) did not make it. The primary outcome was not impaired in the presented 24-month analysis, but the secondary outcomes and the future 5-year analysis may be influenced. We wonder whether performing a “modified” ITT analysis or presenting a complete comparative per protocol analyses would not be more informative. Back to top Article Information Corresponding Author: Marcus Fernando Kodama Pertille Ramos, MD, PhD, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Av Dr Arnaldo 251, São Paulo 01246-000, Brazil (marcus.kodama@hc.fm.usp.br). Published Online: November 18, 2020. doi:10.1001/jamasurg.2020.5180 Conflict of Interest Disclosures: None reported. References 1. Cohen RV, Pereira TV, Aboud CM, et al. Effect of gastric bypass vs best medical treatment on early-stage chronic kidney disease in patients with type 2 diabetes and obesity: a randomized clinical trial.  JAMA Surg. Published online June 3, 2020. doi:10.1001/jamasurg.2020.0420PubMedGoogle Scholar 2. Fergusson D, Aaron SD, Guyatt G, Hébert P. Post-randomisation exclusions: the intention to treat principle and excluding patients from analysis.  BMJ. 2002;325(7365):652-654. doi:10.1136/bmj.325.7365.652PubMedGoogle ScholarCrossref 3. Montedori A, Bonacini MI, Casazza G, et al. Modified versus standard intention-to-treat reporting: are there differences in methodological quality, sponsorship, and findings in randomized trials? a cross-sectional study.  Trials. 2011;12:58. doi:10.1186/1745-6215-12-58PubMedGoogle ScholarCrossref 4. Schauer PR, Kashyap SR, Wolski K, et al. Bariatric surgery versus intensive medical therapy in obese patients with diabetes.  N Engl J Med. 2012;366(17):1567-1576. doi:10.1056/NEJMoa1200225PubMedGoogle ScholarCrossref 5. Nagelkerke N, Fidler V, Bernsen R, Borgdorff M. Estimating treatment effects in randomized clinical trials in the presence of non-compliance.  Stat Med. 2000;19(14):1849-1864.PubMedGoogle ScholarCrossref http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png JAMA Surgery American Medical Association

The Role of Bariatric Surgery in Prevention of Kidney Disease Progression in Moderately Obese Patients With Type 2 Diabetes

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Publisher
American Medical Association
Copyright
Copyright 2020 American Medical Association. All Rights Reserved.
ISSN
2168-6254
eISSN
2168-6262
DOI
10.1001/jamasurg.2020.5180
Publisher site
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Abstract

To the Editor We read with great interest the article by Cohen et al1 that compared the best medical treatment with gastric bypass for the remission of microalbuminuria in early-stage chronic kidney disease in patients with type 2 diabetes and obesity. Knowing the difficulties of carrying out a randomized clinical trial involving surgical procedures, the study flowchart and data analysis always arouse our interest. What sparked our attention in this study was the maintenance of 5 patients (9.8%) who were not operated on in the gastric bypass group performing an intention-to-treat (ITT) analysis. Outcomes at 24 months (Table 2) were presented with the inclusion of these patients, except for albumin and creatinine ratio and metabolic control, which were also presented with the sole inclusion of “complete cases.” The decision to proceed with an ITT, “modified” ITT, or per protocol analysis is often a challenge.2,3 In the landmark study of Schauer et al,4 only 1 of 100 patients assigned to surgical procedure did not undergo sleeve gastrectomy and was not included in the outcome analysis. It is well known that performing postrandomization exclusions may lead to biased estimation of the treatment effect. On the other hand, noncompliance with assigned therapy may mean that the intention-to-treat analysis underestimates the potential benefit of the treatment.5 In this study, performing the surgical procedure is fundamental to the definition of causality, and a considerable number of patients (9.8%) did not make it. The primary outcome was not impaired in the presented 24-month analysis, but the secondary outcomes and the future 5-year analysis may be influenced. We wonder whether performing a “modified” ITT analysis or presenting a complete comparative per protocol analyses would not be more informative. Back to top Article Information Corresponding Author: Marcus Fernando Kodama Pertille Ramos, MD, PhD, Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Av Dr Arnaldo 251, São Paulo 01246-000, Brazil (marcus.kodama@hc.fm.usp.br). Published Online: November 18, 2020. doi:10.1001/jamasurg.2020.5180 Conflict of Interest Disclosures: None reported. References 1. Cohen RV, Pereira TV, Aboud CM, et al. Effect of gastric bypass vs best medical treatment on early-stage chronic kidney disease in patients with type 2 diabetes and obesity: a randomized clinical trial.  JAMA Surg. Published online June 3, 2020. doi:10.1001/jamasurg.2020.0420PubMedGoogle Scholar 2. Fergusson D, Aaron SD, Guyatt G, Hébert P. Post-randomisation exclusions: the intention to treat principle and excluding patients from analysis.  BMJ. 2002;325(7365):652-654. doi:10.1136/bmj.325.7365.652PubMedGoogle ScholarCrossref 3. Montedori A, Bonacini MI, Casazza G, et al. Modified versus standard intention-to-treat reporting: are there differences in methodological quality, sponsorship, and findings in randomized trials? a cross-sectional study.  Trials. 2011;12:58. doi:10.1186/1745-6215-12-58PubMedGoogle ScholarCrossref 4. Schauer PR, Kashyap SR, Wolski K, et al. Bariatric surgery versus intensive medical therapy in obese patients with diabetes.  N Engl J Med. 2012;366(17):1567-1576. doi:10.1056/NEJMoa1200225PubMedGoogle ScholarCrossref 5. Nagelkerke N, Fidler V, Bernsen R, Borgdorff M. Estimating treatment effects in randomized clinical trials in the presence of non-compliance.  Stat Med. 2000;19(14):1849-1864.PubMedGoogle ScholarCrossref

Journal

JAMA SurgeryAmerican Medical Association

Published: Feb 18, 2021

References