No Benefit to Reducing Blood Pressure Below 140/90
Posted by medconsumers on September 10, 2009
An Interview with Hypertension Expert, J. M. Wright, MD, PhD
By Maryann Napoli
This story is right up my alley: a prevailing medical belief is found to be baseless and perhaps even harmful. Whether they have heart disease or not, people with high blood pressure are usually put on multiple drug therapy to reduce their chances of having a heart attack or stroke. No problem there, if it weren’t for the fact that the definition of high blood pressure was expanded several times over the years, thus turning more and more of us into potential drug customers. (Expanded definitions of abnormal can be seen in other health “problems” like cholesterol, high blood sugar, low bone density—just to name a few—usually send me looking for the inevitable pharmaceutical industry involvement.) Today, a “lower the better” ideal guides the treatment of high blood pressure.
A new Cochrane review identified the seven trials that had tested this ideal and found that it didn’t hold up to scientific scrutiny. Using more drugs to reduce blood pressure lower than the standard target, 140/90 mmHg, did not prolong survival or reduce stroke, heart attack, heart failure or kidney failure. The trials had a combined total of more than 22,000 participants who were followed about 3 ½ years.
To make sense of this new information, I turned to a co-author of this Cochrane review, James M. Wright, MD, PhD, physician, researcher, pharmacologist, and professor at the University of British Columbia, Vancouver.
MN: What made you think of asking this most basic hypertension research question: Do people benefit from taking drugs to lower their blood pressure below 140/90?
JMW: We realized—more than 10 years ago—that this is one of the most important questions that needed to be answered in terms of the management of people with high blood pressure. And we knew that the way to answer it was to look at randomized, controlled trials where drug-treated people were randomly assigned to achieve either the standard blood pressure target [140/90] or something lower.
MN: How good are the trials?
JMW: The most important trial in our review is the Hypertension Optimal Treatment (HOT) trial. It had about 19,000 participants and is the largest one designed specifically to answer the question of whether getting the blood pressure lower than 140/90 actually benefits people. Yet the way this trial’s results were published in the Lancet was very biased. It appeared that the authors were not happy with the results of the randomized trial, which showed no benefit with the lower blood pressure targets.
MN: Was the HOT trial industry-funded?
JMW: Yes, the authors of the HOT trial were all big experts in hypertension. All were working closely with drug companies that make blood pressure-lowering drugs, and it was a drug company-funded trial. This randomized trial showed no benefit for lower blood pressure targets whatsoever.
MN: It was troubling to read that none of the trials in this review had looked at the potential harms of using drugs to get blood pressure lower than 140/90. That means we don’t have a full picture of the side effects of hypertension drugs, though they’ve been in use for decades.
JMW: The authors almost certainly looked for harms in these trials. You’re supposed to track serious adverse events in these trials. However, serious adverse event data were not reported from the HOT trial, and this could mean that the drug companies are withholding unfavorable findings related to their drugs.
MN: I noticed that the participants of all seven trials in your review were between the ages of 50 and 69 years. Does that means no one was over 69 in the trials?
JMW: The HOT trial had participants up to the age of 80 years.
MN: But if the researchers put the people, aged 69 to 80 years, with younger people and don’t separate the results according to age, then you really don’t have specific benefit/harms information for those of advanced age, do you?
JMW: That’s true.
MN: What about women?
JMW: I’m disappointed to tell you that we found no breakdown of the participants of the trials in this review by gender. And since we don’t have separate data for women, we don’t know whether the harms predominated in women, which is possible. I’m very aware of that. Women seem to be more prone to harms from drugs in general than men.
JMW: My theory is that women, on average, weigh significantly less than men, and we [doctors] usually give the same doses to men and women. So women in general are getting a higher dose per kilogram. And that’s going to play out in terms of more harms than in men. In all the clinical trials, the same dose of the drug is given to men and to women.
MN: Last spring, I wrote about a new meta-analysis of hypertension drug trials, entitled, “Drugs for all at high risk whether blood pressure is high or not.” The findings supported the use of the so-called polypill to lower the risk of heart disease in everyone over the age of 55. Instead of the current focus on blood pressure measurement—and driving people crazy when they can’t bring their pressure down after trying multiple drugs—the authors suggest a shift in focus to reducing drug side effects with lower drug doses. What do you think?
JMW: The most important thing to look at first, before you even read that meta-analysis, is the authors’ conflict of interest.
MN: Drs. Wald and Law disclosed their conflicts at the end of their paper.
JMW: Yes, they own a patent on the idea of the polypill, which includes three antihypertensives, so their meta-analysis basically comes up with a conclusion that favors the polypill. It’s a gross conflict of interest—much worse than a doctor who is a speaker for, or receiving a grant from a drug company.
MN: But I liked some of Law’s and Wald’s conclusions, for example, most of the antihypertensive drugs are now off patent (and therefore, inexpensive) and largely interchangeable. And I’m familiar enough with your work to know that you would probably agree with their promotion of lower doses of these drugs because so many people with high blood pressure stop taking their drugs due to adverse effects.
JMW: Yes, we do agree that lower doses are almost as effective as the standard doses.
MN: What about their point that the five drug classes prescribed for high blood pressure are largely interchangeable? Do you agree with that?
JMW: Ideally, you would want to be on an anti-hypertensive drug that has been shown to reduce morbidity [non-fatal stroke, non-fatal heart attack] and mortality.
MN: That leaves you with the least expensive drug of all—thiazide diuretics.
JMW: The morbidity and mortality evidence is, by far, stronger for the thiazide diuretics than for any other drug classes.
MN: One thing bothered me about the polypill promoters. They said that halving the standard dose reduces adverse effects, claiming that the “polypill would cause symptoms in 8-15% of people (depending on the precise formulation).” What is known about adverse effects of these drugs at half dose?
JMW: We know that most adverse effects of blood pressure lowering drugs are dose-related, so lower doses are likely to have fewer adverse effects.
MN: Do you think it’s reasonable—based on the findings from your new review—for drug-treated people with blood pressures lower than 140/90 to ask their doctors to reduce the dose?
JMW: Yes, it is reasonable. Patients who have been referred to me often say, “Do I really need all these drugs?” And my reaction usually is, “We probably should start thinking of cutting back.”
MN: As recently as 2003, having a blood pressure of 120/80 was considered normal, but now it’s “prehypertension,” according to one important guidelines committee. I know that some people are put on drugs for it, but that could be just here in the U.S.
JMW: The standard of care is aggressive everywhere. [Here in British Columbia] physicians would not give any drugs to people whose blood pressure is 120/80, but the average doctor wouldn’t stop drug therapy [or lower the dose] in people whose blood pressure is this level. In the drug-treated patients I follow in the High Blood Pressure Clinic whose blood pressure is consistently low like that [120/80], I say, “you probably don’t need all these drugs, let’s try going off them gradually one at a time.”
Dr. Wright says that he has no conflict of interest pertaining to high blood pressure drugs.
A 2012 Cochrane review, co-authored by Dr. Wright, could find no proven benefit to treating people whose blood presure is under 159/99. Read this An earlier interview with Dr. Wright about safe drug use. read this
Think you’re anti-hypertension drug dose is too high? Read this