Statins and blood pressure

Tuesday April 15 2008

The cholesterol-lowering drugs statins may also reduce blood pressure, reports The Daily Telegraph today. American scientists have found that the statins can “have a ‘significant’ effect on patients suffering from high blood pressure". The statins could help the 16 million people in Britain with high blood pressure, which “raises the risk of heart disease, strokes, kidney disease and dementia”, the Telegraph adds.

The newspaper report is based on a trial which compared two different statins with an inactive placebo pill. Contrary to the newspaper reports, most of the 937 people in this trial did not have high blood pressure; therefore, it is not possible to say from this study whether statins have similar effects in people with high blood pressure. Although statins are used specifically to reduce cholesterol, these findings indicate that there may be an additional beneficial effect on blood pressure, and that this may be contributing to the reduction in cardiovascular events seen with these drugs.

Where did the story come from?

Dr Beatrice Golomb and colleagues at the University of California carried out this research. The study was funded by the National Heart, Lung, and Blood Institute, the National Institutes of Health and the UCSD General Clinical Research Center. It was published in the Archives of Internal Medicine , a peer-reviewed medical journal.

What kind of scientific study was this?

This was a double-blind randomised controlled trial designed to compare two different statins and a placebo treatment.

The researchers enrolled adults from southern California with low-density lipoprotein (LDL) cholesterol levels of 115 to 190mg/dL (3.0 to 4.8mmol/L), and without known cardiovascular disease or diabetes. They randomly assigned these people to receive one of three treatments for six months: simvastatin (20mg), pravastatin sodium (40mg) or placebo. Before the study started, the researchers measured the participants’ blood pressure in the morning while seated, they measured it again one, six and eight months into the study.

The researchers compared changes in blood pressure at six months between the statin groups and the placebo group. They also looked blood pressure specifically in people who did not have raised blood pressure at the start of the study and who were not taking any blood pressure medications, and at the effect of each statin individually. Blood pressure was not the main outcome of interest (primary outcome) of this study. Of the 1,016 people in the study, 43 did not have blood pressure measurements at the start of the study and were excluded, this left 973 people for analysis.

What were the results of the study?

The researchers found that statins “modestly” reduced blood pressure compared with placebo. They reduced both systolic and diastolic blood pressure by about 2mmHg on average compared with placebo, and these reductions were statistically significant.

Similar reductions were seen when the researchers looked at each statin individually, and at people who did not have high blood pressure at the start of the study and were not taking blood pressure medication. The difference in blood pressure between statin and placebo groups was no longer significant two months after the participants stopped taking their statins.

What interpretations did the researchers draw from these results?

The researchers concluded that the two different types of statins tested reduced blood pressure compared with placebo, even in people with normal blood pressure. They said that these reductions “may contribute to the reduced risk of stroke and cardiovascular events reported on statins”.

What does the NHS Knowledge Service make of this study?

This was a well-designed study which lends support to the idea that some of the effects of statins on cardiovascular outcomes may be related to an effect on blood pressure. Limitations to the study include:

  • Blood pressure was only measured once at each screening. Although this reading may not have been representative of a person’s regular blood pressure, the authors point out that as all groups were measured in the same way, this should not bias the results in favour of any group.
  • The group measured did not have cardiovascular disease, and most did not have high blood pressure. The findings of this study may not apply to people with these characteristics. Most participants were white, and the results may not apply to other ethnic groups.

It is unclear what the implications, if any, of these findings are for clinical practice. There are medications that can more effectively reduce blood pressure and most people who are at high risk for future heart attacks or strokes will already be on both blood pressure lowering medication and drugs, such as statins, which lower cholesterol.

Sir Muir Gray adds...

These risk factors are caused not by chemicals but by our lifestyle. The first thing that people who are at risk should do is change their lifestyle – stop smoking, eat less and take 3,000 extra steps a day.

Analysis by Bazian
Edited by NHS Choices