Final Research Report
View this project's final research report.
More About This Research
Related PCORI Dissemination and Implementation Project
Evidence for Decisions
Comparing Two Types of Weight Loss Surgery
Bariatric surgery can help people with obesity lose weight, among other potential benefits. But surgery can also cause harm, and outcomes may vary across different procedures. A recent PCORI-funded study compared the benefits and harms of the two most common types of bariatric surgery. The findings can help clinicians and patients work together to make informed decisions regarding patient care.
Results of This Project
Related Journal Citations
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Peer review of PCORI-funded research helps make sure the report presents complete, balanced, and useful information about the research. It also assesses how the project addressed PCORI’s Methodology Standards. During peer review, experts read a draft report of the research and provide comments about the report. These experts may include a scientist focused on the research topic, a specialist in research methods, a patient or caregiver, and a healthcare professional. These reviewers cannot have conflicts of interest with the study.
The peer reviewers point out where the draft report may need revision. For example, they may suggest ways to improve descriptions of the conduct of the study or to clarify the connection between results and conclusions. Sometimes, awardees revise their draft reports twice or more to address all of the reviewers’ comments.
Peer reviewers commented and the researchers made changes or provided responses. Those comments and responses included the following:
- The reviewers asked why the researchers did not perform propensity score analyses on some specific parts of the study, such as safety outcomes, to account for any differences between groups in this observational study. The researchers explained that they found the propensity score adjustments did not change results enough to warrant accepting certain assumptions and checking propensity distributions. In addition, because the hypotheses in these studies were associative instead of causal, the reviewers felt that the covariate adjustment was sufficient without a propensity score adjustment.
- The reviewers asked whether the researchers specified subgroup analyses in advance and whether they were driven by hypotheses. The researchers responded that they specified all subgroup analyses in advance but that they considered the analyses exploratory rather than driven by hypotheses.
- The reviewers asked why in the qualitative study, patient feedback was sought in focus groups rather than in individual interviews. Since obesity and bariatric surgery can be socially sensitive topics, the reviewers noted that having to answer questions in a group setting may have affected responses. The researchers said funding constraints did not allow for individual interviews, particularly since they wanted to maximize sample size and representation of patients from different parts of the country. They acknowledged that using focus groups was a limitation of the study.
- The reviewers asked why the frequency of obesity-related cancers, including colorectal cancer, was not analyzed as an outcome. The researchers explained that they excluded patients with certain types of cancers, especially gastrointestinal (GI) cancers, because some patients with GI cancer will undergo a procedure for the cancer that is coded the same as bariatric surgery in electronic health records.
Conflict of Interest Disclosures
^Kaiser Permanente acquired Group Health Cooperative in February 2017.
- Has Results
- Completed; PCORI Public and Professional Abstracts, and Final Research Report Posted
- Research Conducted Using PCORnet®
These are the broad terms we use to categorize our funded research studies; specific diseases or conditions are included within the appropriate larger category. Note: not all of our funded projects focus on a single disease or condition; some touch on multiple diseases or conditions, research methods, or broader health system interventions. Such projects won’t be listed by a primary disease/condition and so won’t appear if you use this filter tool to find them.
- Nutritional and Metabolic Disorders
PCORI is interested in research that seeks to better understand how different clinical and health system options work for different people. These populations are frequently studied in our portfolio or identified as being of interest by our stakeholders.
- Children -- 18 and under
- Individuals with Multiple Chronic/co-morbid Conditions
- Older Adults
- Racial/Ethnic Populations
- Obesity Observational Research Initiative
PCORI funds comparative clinical effectiveness research (CER) studies that compare two or more options or approaches to health care, or that compare different ways of delivering or receiving care.
- Other Clinical Interventions
- Accelerating PCOR and Methodological Research
The state where the project originates, or where the primary institution or organization is located.