Maintained intentional weight loss reduces cardiovascular outcomes: results from the Sibutramine Cardiovascular OUTcomes (SCOUT) trial


Ian D. Caterson, Boden Institute of Obesity Nutrition, Exercise and Eating Disorders, University of Sydney, NSW, Australia.


Aim: The Sibutramine Cardiovascular OUTcomes trial showed that sibutramine produced greater mean weight loss than placebo but increased cardiovascular morbidity but not mortality. The relationship between 12-month weight loss and subsequent cardiovascular outcomes is explored.

Methods: Overweight/obese subjects (N = 10 744), ≥55 years with cardiovascular disease and/or type 2 diabetes mellitus, received sibutramine plus weight management during a 6-week Lead-in Period before randomization to continue sibutramine (N = 4906) or to receive placebo (N = 4898). The primary endpoint was the time from randomization to first occurrence of a primary outcome event (non-fatal myocardial infarction, non-fatal stroke, resuscitated cardiac arrest or cardiovascular death).

Results: For the total population, mean weight change during Lead-in Period (sibutramine) was −2.54 kg. Post-randomization, mean total weight change to Month 12 was −4.18 kg (sibutramine) or −1.87 kg (placebo). Degree of weight loss during Lead-in Period or through Month 12 was associated with a progressive reduction in risk for the total population in primary outcome events and cardiovascular mortality over the 5-year assessment. Although more events occurred in the randomized sibutramine group, on an average, a modest weight loss of approximately 3 kg achieved in the Lead-in Period appeared to offset this increased event rate. Moderate weight loss (3–10 kg) reduced cardiovascular deaths in those with severe, moderate or mild cardiovascular disease.

Conclusions: Modest weight loss over short-term (6 weeks) and longer-term (6–12 months) periods is associated with reduction in subsequent cardiovascular mortality for the following 4–5 years even in those with pre-existing cardiovascular disease. While the sibutramine group experienced more primary outcome events than the placebo group, greater weight loss reduced overall risk of these occurring in both groups.