Long-Term Outcome of Bariatric Surgery
http://www.100md.com
《新英格兰医药杂志》
To the Editor: The primary outcome of the Swedish Obese Subjects (SOS) Study, reported by Sj?str?m et al. (Dec. 23 issue),1 was mortality, but only secondary outcomes are presented. There is a statement in the report that "the safety monitoring committee found no reason to interrupt the study prematurely because of positive effects or harm." This report should not have been published without data on the primary outcome. In the absence of a significant effect on the primary outcome, the authors present the attractive changes that occurred in secondary outcomes. Solomon and Dluhy, in the accompanying editorial,2 emphasize that it "is not known . . . whether . . . benefits [of changes in body weight and so forth] translate into reduced rates of . . . death." But this is not enough. If the significant changes described are really of benefit, why do they not translate into a reduced death rate? A simple explanation is that these changes are not as good for health as they appear to be. If the outcome was not changed under the treatment, the most likely explanation is that the treatment is not effective.
Vasiliy V. Vlassov, M.D.
Russian Branch of the Nordic Cochrane Center
Moscow 109451, Russia
vlassov@cochrane.ru
References
Sj?str?m L, Lindroos AK, Peltonen M, et al. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. N Engl J Med 2004;351:2683-2693.
Solomon CG, Dluhy RG. Bariatric surgery -- quick fix or long-term solution? N Engl J Med 2004;351:2751-2753.
Dr. Sj?str?m replies: Dr. Vlassov suggests that our article on changes in risk factors 10 years after surgery in the SOS Study should not have been published, since the primary outcome of SOS (i.e., total mortality) was not reported. SOS is a controlled intervention trial that was started in 1987 with plans for continuation until 2020. In addition to the primary end point, the study has several secondary end points, one of which is changes in cardiovascular risk factors. Evaluation of secondary end points has resulted in a substantial number of publications related to SOS, and more will probably follow.
In accordance with the original study protocol, a report on total mortality will appear when the follow-up has reached 40,000 person-years (i.e., when the approximately 4000 subjects have been followed on average for 10 years). This was not the case when the report was submitted to the Journal, and the safety monitoring committee found no reason to interrupt the study prematurely.
Lars Sj?str?m, M.D., Ph.D.
Sahlgrenska University Hospital
S-41345 G?teborg, Sweden
Vasiliy V. Vlassov, M.D.
Russian Branch of the Nordic Cochrane Center
Moscow 109451, Russia
vlassov@cochrane.ru
References
Sj?str?m L, Lindroos AK, Peltonen M, et al. Lifestyle, diabetes, and cardiovascular risk factors 10 years after bariatric surgery. N Engl J Med 2004;351:2683-2693.
Solomon CG, Dluhy RG. Bariatric surgery -- quick fix or long-term solution? N Engl J Med 2004;351:2751-2753.
Dr. Sj?str?m replies: Dr. Vlassov suggests that our article on changes in risk factors 10 years after surgery in the SOS Study should not have been published, since the primary outcome of SOS (i.e., total mortality) was not reported. SOS is a controlled intervention trial that was started in 1987 with plans for continuation until 2020. In addition to the primary end point, the study has several secondary end points, one of which is changes in cardiovascular risk factors. Evaluation of secondary end points has resulted in a substantial number of publications related to SOS, and more will probably follow.
In accordance with the original study protocol, a report on total mortality will appear when the follow-up has reached 40,000 person-years (i.e., when the approximately 4000 subjects have been followed on average for 10 years). This was not the case when the report was submitted to the Journal, and the safety monitoring committee found no reason to interrupt the study prematurely.
Lars Sj?str?m, M.D., Ph.D.
Sahlgrenska University Hospital
S-41345 G?teborg, Sweden