Gastric bypass has better outcomes than gastric b and procedures for long-term weight loss , type 2 diabetes control and remission , hypertension , and hyperlipidemia .
Insufficient evidence exists regarding long-term outcomes for gastric sleeve resections
IMPORTANCE Bariatric surgery is an accepted treatment for obesity .
Despite extensive literature , few studies report long-term follow-up in cohorts with adequate retention rates .
OBJECTIVE To assess the quality of evidence and treatment effectiveness 2 years after bariatric procedures for weight loss , type 2 diabetes , hypertension , and hyperlipidemia in severely obese adults .
A comparison of observational studies and randomized, controlled trials
BACKGROUND : For many years it has been cl aim ed that observational studies find stronger treatment effects than r and omized , controlled trials . We compared the results of observational studies with those of r and omized , controlled trials . METHODS : We search ed the Abridged Index Medicus and Cochrane data bases to identify observational studies reported between 1985 and 1998 that compared two or more treatments or interventions for the same condition . We then search ed the Medline and Cochrane data bases to identify all the r and omized , controlled trials and observational studies comparing the same treatments for these conditions . For each treatment , the magnitudes of the effects in the various observational studies were combined by the Mantel-Haenszel or weighted analysis -of-variance procedure and then compared with the combined magnitude of the effects in the r and omized , controlled trials that evaluated the same treatment . RESULTS : There were 136 reports about 19 diverse treatments , such as calcium-channel-blocker therapy for coronary artery disease , appendectomy , and interventions for subfertility .  In most cases , the estimates of the treatment effects from observational studies and r and omized , controlled trials were similar . In only 2 of the 19 analyses of treatment effects did the combined magnitude of the effect in observational studies lie outside the 95 percent confidence interval for the combined magnitude in the r and omized , controlled trials . CONCLUSIONS : We found little evidence that estimates of treatment effects in observational studies reported after 1984 are either consistently larger than or qualitatively different from those obtained in r and omized , controlled trials
Gastric bypass has better outcomes than gastric b and procedures for long-term weight loss , type 2 diabetes control and remission , hypertension , and hyperlipidemia .
Insufficient evidence exists regarding long-term outcomes for gastric sleeve resections
IMPORTANCE Bariatric surgery is an accepted treatment for obesity .
Despite extensive literature , few studies report long-term follow-up in cohorts with adequate retention rates .
OBJECTIVE To assess the quality of evidence and treatment effectiveness 2 years after bariatric procedures for weight loss , type 2 diabetes , hypertension , and hyperlipidemia in severely obese adults .