NEW ORLEANS — Statins produce a small but significant blood pressure reduction that might explain some of the benefits that these drugs provide.
Treatment with either simvastatin or pravastatin led to significant reductions of both systolic and diastolic BP that averaged about 2.5 mm Hg in a controlled study with 1,016 patients, Beatrice A. Golomb, M.D., reported at the annual scientific sessions of the American Heart Association.
“Some patients who are on the cusp of having hypertension and are not on antihypertensive therapy may benefit from the statin effect,” which may help them continue to avoid needing a blood pressure-lowering drug, said Dr. Golomb, a cardiologist at the University of California, San Diego. This modest degree of BP reduction may explain the ability of statin therapy to cut the risk of stroke, a finding that has been hard to attribute to lipid-lowering effects.
The study enrolled men and postmenopausal women who did not have heart disease, diabetes, or hypertension, and whose LDL-cholesterol level was 115–190 mg/dL. These patients were randomized to treatment with 20 mg/day simvastatin, 40 mg/day pravastatin, or placebo, and the treatment continued for 6 months.
After 6 months of treatment, systolic BP had fallen by an average of 2.8 mm Hg in the simvastatin group and by 2.5 mm Hg in the pravastatin group, compared with baseline. Diastolic pressures had dropped by an average of 2. 7 mm Hg and 2.5 mm Hg, compared with baseline in the simvastatin and pravastatin groups, respectively. Once patients were off statin treatment for 2 months, these BP reductions largely disappeared.
The results of a second study presented at the meeting suggested that the blood pressure-lowering effect of a statin is independent of the drug's lipid-lowering effect. This analysis used data collected from the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT). This study enrolled more than 19,000 patients with hypertension but without known coronary artery disease to an intervention trial that was primarily designed to compare the effects of different antihypertensive regimens. The study also randomized a 10,305-patient subgroup to treatment with either 10 mg of atorvastatin daily or placebo. The blood pressures recorded in this subset were evaluated in a posthoc analysis to explore whether atorvastatin had any effect on blood pressure.
Although all patients in the study were on combined regimens of antihypertensive drugs, those who also received atorvastatin had small but consistently lower systolic and diastolic BPs than the patients who did not receive statin therapy, reported Bjorn Dahlof, M.D., professor of medicine at the University of Göteborg (Sweden). The 5,168 patients treated with atorvastatin had an average systolic pressure that was about 1 mm Hg lower than that among 5,137 patients treated with placebo at several times during 3 years of follow-up. Diastolic BP averaged about 0.6 mm Hg lower in the atorvastatin group, compared with those on placebo.
Although these differences in pressure were very small, they were statistically significant because the study involved so many people, Dr. Dahlof said.
A further analysis was then done to see if there was a correlation between the blood pressure-lowering effect of atorvastatin and patients' levels of total or LDL cholesterol.
This assessment showed virtually no link between the two effects. Lipid lowering “explained perhaps 1%” of the effect of atorvastatin on blood pressure, Dr. Dahlof reported.
Statins probably have other effects that lower blood pressure, such as activating nitric oxide synthetase, down-regulating angiotensin II, and enhancing flow-mediated vasodilation, Dr. Golomb said.