Background/objectives: The Sibutramine Cardiovascular OUTcomes (SCOUT) trial showed a significantly increased relative risk of nonfatal cardiovascular events, but not mortality, in overweight and obese subjects receiving long-term sibutramine treatment with diet and exercise. We examined the relationship between early changes (both increases and decreases) in body weight and blood pressure, and the impact of these changes on subsequent cardiovascular outcome events.
Subjects/methods: A total of 9804 male and female subjects, aged 55 years or older, with a body mass index of 27-45 kg m(-2) were included in this current subanalysis of the SCOUT trial. Subjects were required to have a history of cardiovascular disease and/or type 2 diabetes mellitus with at least one cardiovascular risk factor (hypertension, dyslipidemia, current smoking or diabetic nephropathy) to assess cardiovascular outcomes. Post hoc subgroup analyses of weight change (categories) and blood pressure were performed overall and by treatment group (6-week sibutramine followed by randomized placebo or continued sibutramine). The primary outcome event (POE) was a composite of nonfatal myocardial infarction, nonfatal stroke, resuscitated cardiac arrest or cardiovascular death. Time-to-event analyses of the POE were performed using Cox regression models with factors for treatment, subgroups and interactions.
Results: During the initial 6-week sibutramine treatment period, systolic blood pressure decreased progressively with increasing weight loss in hypertensive subjects (-8.1±10.5 mm Hg with <5 kg weight loss to -10.8±11.0 mm Hg with ⩾5 kg weight loss). The highest POE incidence occurred mainly in groups with increases in both weight and blood pressure. However, with long-term sibutramine treatment, a markedly lower blood pressure tended to increase POEs.
Conclusion: Modest weight loss and modest lower blood pressure each reduced the incidence of cardiovascular events, as expected. However, the combination of early marked weight loss and rapid blood pressure reduction seems to be harmful in this obese elderly cardiovascular diseased population.
Trial registration: ClinicalTrials.gov NCT00234832.