Obesity is associated with increased mortality. Weight loss improves cardiovascular
risk factors, but no prospective interventional studies have reported whether weight
loss decreases overall mortality. In fact, many observational studies suggest that
weight reduction is associated with increased mortality.
The prospective, controlled Swedish Obese Subjects study involved 4047 obese subjects.
Of these subjects, 2010 underwent bariatric surgery (surgery group) and 2037 received
conventional treatment (matched control group). We report on overall mortality during
an average of 10.9 years of follow-up. At the time of the analysis (November 1, 2005),
vital status was known for all but three subjects (follow-up rate, 99.9%).
The average weight change in control subjects was less than +/-2% during the period
of up to 15 years during which weights were recorded. Maximum weight losses in the
surgical subgroups were observed after 1 to 2 years: gastric bypass, 32%; vertical-banded
gastroplasty, 25%; and banding, 20%. After 10 years, the weight losses from baseline
were stabilized at 25%, 16%, and 14%, respectively. There were 129 deaths in the control
group and 101 deaths in the surgery group. The unadjusted overall hazard ratio was
0.76 in the surgery group (P=0.04), as compared with the control group, and the hazard
ratio adjusted for sex, age, and risk factors was 0.71 (P=0.01). The most common causes
of death were myocardial infarction (control group, 25 subjects; surgery group, 13
subjects) and cancer (control group, 47; surgery group, 29).
Bariatric surgery for severe obesity is associated with long-term weight loss and
decreased overall mortality.
Copyright 2007 Massachusetts Medical Society.