Sixteen RCTs were included in the review. In addition, one economic evaluation was also included in the analysis.
The methodological quality of the included trials was judged to be moderate to good.
The majority of the placebo-controlled trials and pooled estimates suggested that sibutramine produced a statistically-significant greater weight loss than placebo at all of the observed end points. The WMD for weight change at 8 weeks (3 trials) was -3.4 kg (95% CI : -4.22, 2.58, P<0.00001). The mean difference for weight change ranged from -4.0 to 9.1 kg at 6 months, and from -4.1 to 4.8 kg at one year.
The most frequent dosing regimen was 10 to 20 mg/day. The findings suggested a dose-effect relationship in terms of weight loss. Sibutramine was also associated with better weight maintenance relative to placebo; the difference was statistically significant.
Results from mainly small trials showed that sibutramine produced more favourable outcomes in terms of loss of fat mass, reduction in body mass index, and losses of at least 5 and 10% of initial body weight.
Between-group differences for waist circumference, hip circumference, and waist-hip ratio did not reach statistical significance.
Similar results for weight loss were found in trials recruiting only participants with type 2 diabetes; between-group differences for changes in indicators of glycaemic control were not usually statistically significant.
Sibutramine use was associated with small, statistically-significant increases in pulse rate, heart rate and blood-pressure.
Eleven participants in the sibutramine 15-mg group and 5 in the placebo group withdrew due to adverse events.