Graz, Austria - People with high blood pressure who lose weight by dieting or by taking the weight-loss drug orlistat (Xenical, Roche) also appear to achieve reductions in diastolic and systolic blood pressure, a new meta-analysis suggests [1]. Authors of the new research, however, say that the same blood-pressure benefits were not seen if weight loss was achieved by taking the diet drug sibutramine (Meridia/Reductil, Abbot); moreover, the existing body of research does not explain whether these reductions in blood pressure are associated with meaningful reductions in cardiovascular events.

According to the first author on the study, Dr Karl Horvath (University of Graz, Austria), there are "no clear-cut answers."

"Reducing your body weight will lower your blood pressure," he told heartwire. "Whether this will translate into reducing your risk of heart attack, stroke, or death later on is unclear."

Horvath and colleagues looked for any trials that used diets, drugs, or invasive procedures to treat weight loss in people with hypertension, had a sufficient follow-up period (at least 24 weeks), and included information on at least one of the following: mortality, cardiovascular outcomes, adverse events, or blood-pressure effects. They report that of 48 articles identified, most were on dietary interventions, five were on orlistat, and five were on sibutramine, but that there were no suitable studies of rimonabant (Accomplia, Sanofi-Aventis) or of surgical interventions for weight loss. While both pharmacological interventions, as well as the diet studies, pointed to greater weight loss than in control groups or placebo-treated subjects, only the orlistat and diet interventions appeared to lower blood pressure. And according to the authors, despite their intention of demonstrating a link between weight loss and cardiovascular outcomes in hypertensives, they were forced to conclude that "currently no randomized controlled trials designed to answer this question are available."

"Since we did not find a clear beneficial effect of sibutramine on blood pressure, I do think that orlistat indeed seems to be the safer choice," Horvath commented to heartwire. "But since we can not be sure that patients will also benefit in terms of lowering their risk of hard end points like CV events or death, it is hard to say what the preferred drug would be."

Given the lack of blood-pressure lowering with sibutramine, the fact that dietary interventions had fewer side effects than orlistat, and that information on rimonabant and surgical interventions was lacking, Horvath said that at least for the time being, his recommended intervention would be diet based.

"It seems clear that reducing body weight will lead to a reduction of blood pressure," Horvath said. "But, for now, it is still unclear whether this will eventually lead to a reduction in death, myocardial infarction, or other cardiovascular events."