Relation between weight loss and causes of death in patients with cardiovascular disease: finding from the SCOUT trial

AIMS: Obesity is associated with an increased incidence of mortality. The Sibutramine Cardiovascular Outcomes (SCOUT) trial can provide the first evidence of the effect of intentional weight loss on mortality in an obese population at high risk.

METHODS: SCOUT was a randomized, double-blind, placebo-controlled trial testing sibutramine vs. placebo. Eligibility for the trial required both men and women aged at least 55 years, with BMI of at least 27 kg/m and 45 kg/m or less. Study participants with type 2 diabetes mellitus (T2DM) only should have at least one other risk factor defined as hypertension, dyslipidaemia, smoking, or diabetic nephropathy, and/or they had a history of cardiovascular disease. Study participants were stratified in three groups: patients with T2DM, patients with a prior cardiovascular event but without diabetes, and patients with both T2DM and a prior cardiovascular event.The relationship between weight loss and mortality (all-cause, cardiovascular, and noncardiovascular) was investigated with Cox regression models.

RESULTS: The main study showed that all-cause mortality was not different in patients allocated to sibutramine or placebo. This ancillary analysis demonstrates that there is a general trend showing higher mortality in patients with the greatest weight loss (weight reduction >10 kg) and in those with increasing weight (>1 kg). If integrated weight loss (area under the curve from baseline to 12 months) is used, these observations are confirmed. The impact of substantial weight loss on mortality is marked in those dying of noncardiovascular causes, specifically cancer.

CONCLUSION: The relationship between weight change and mortality differs for cardiovascular and noncardiovascular mortality.