Lose weight, lower your blood pressure

By April Clarkson, April 25th, 2013 | Health | 2 Comments

Weight loss is achievable through dieting and also with the aid of the slimming drugs orlistat and sibutramine. A review of the evidence shows how losing weight does help people with hypertension to lower their blood pressure. However, we don’t yet know if these gains are translated into lower mortality rates through decreased risk of heart attacks and strokes.

Cardiovascular disease (CVD) continues to be a massive public health problem around the world, with heart attacks, strokes and related conditions accounting for nearly 17 million deaths a year. In developed countries, heart disease and stroke are the leading two causes of death, and the CVD burden continues to rise in developing countries. Both heart disease and stroke are preventable, in many cases. A leading risk factor for CVD is raised blood pressure, or hypertension. Lowering blood pressure in hypertensive patients is a very effective way of lowering their CVD risk. And lifestyle changes, such as weight loss and quitting smoking, can lower blood pressure. Researchers in Austria and Germany reveal the strength of evidence behind the advice to lose some weight if you want to lower your blood pressure for health reasons.

The research team set out to discover the long-term effect of dietary interventions intended to shed weight, including the use of medication. They also wanted to see what effect weight loss had on health outcomes such as blood pressure, all cause mortality, and mortality from CVD. They found seven studies about diet and weight loss and eight involving medication and weight loss. Of the latter, four involved orlistat and four involved sibutramine. There were no relevant studies about rimonabant or surgical weight loss. The diet studies involved 1632 patients in all, aged between 45 and 66 years. The orlistat studies covered 3132 patients aged between 46 and 55, while the sibutramine studies involved 610 patients aged between 46 and 53. All the patients had a degree of hypertension and the trials were placebo-controlled.

Participants assigned to a weight loss diet, orlistat or sibutramine all lost more weight than those in the placebo group and were able to maintain their weight loss through follow up. There were also significant decreases in both systolic (top figure) and diastolic (bottom figure) blood pressure. A reduction in body weight of about eight pounds was enough to achieve a fall of 6 mm Hg in systolic blood pressure with diet. For those on orlistat, the corresponding figure was 2.5 mm Hg. What is concerning is that sibutramine did not decrease blood pressure and in some participants, there was even an increase in systolic blood pressure. And orlistat was linked with side effects, mainly of a gastrointestinal nature. None of the studies could say whether these improvements in blood pressure related to weight loss had improved long-term health outcomes in terms of reduced rates of cardiovascular disease.

This analysis shows the value of the conventional dietary approach to weight loss. And you need only lose a few pounds to start seeing the benefits in terms of lowered blood pressure. Medications that aid weight loss, like orlistat and sibutramine, do not seem to be as good as dietary interventions in improving blood pressure. Of course, these medications are relatively new and it is likely too soon to know what role they can play in reducing cardiovascular disease risk. Sibutramine should not, at least on the current evidence, be used to help reduce blood pressure through weight loss. And we need to know more about the relationship between weight loss, blood pressure, and heart disease and stroke.