QUICKLINKS AND VIEW OPITONS
Treating High Blood Pressure: What Can You Believe? By Dr. Malcolm Kendrick
Friday, January 29, 2010 1:58 pm Email this article
For those of us who enjoy the use of weasel words and non-scientific rubbish dressed up as fact, this is indeed a grand territory to explore….
I have written about hypertension a couple of times. So I thought that I should throw my hat into the ring about the controversy surrounding the ALLHAT trial. A trial which wins my official tortuous acronym award? ALLHAT stands for the Antihypertensive and Lipid-Lowering treatment to prevent Heart Attack Trial.
(This article was written by Malcolm Kendrick, MD, author of the wonderful, eye-opening, paradigm-shifting book The Great Cholesterol Con: The Truth About What Really Causes Heart Disease and How to Avoid It .) Clinical Trial And Their Acronyms
Clinical trials try to have memorable acronyms
Actually, my favourite acronym is the CARPORT trial. This stands for, wait for it: the Coronary Artery Restenosis Prevention On Repeated Thomboxane A2-receptor blockade. There are others, the TIBET, ALIVE, LIFE, LIMIT. Rule number one, your clinical trial must have a memorable acronym otherwise, self-evidently, no-one will remember it.
ALLHAT Trial, Patients and Duration
ALLHAT trial: 40,000 people with 6 years of followup
Anyway, what is the ALLHAT trial, and what has it shown? The first thing to note is that it is a big trial, with more than 40,000 patients in it. And it is also a long trial; the followup was designed to last at least 6 years. So the results carry a little more weight than the old ‘five patient, twenty eight day study in Tibetan Yak herders.’
ALLHAT Trial: Drugs and Outcomes
ALLHAT trial: Diuretic vs calcium channel blocker vs ACE inhibitor vs Alpha blocker; fatal CHD and non-fatal heart attacks
The trial had two parts, an antihypertensive part and a lipid lowering part. The purpose of the trial was to assess the incidence of fatal coronary heart disease and nonfatal MI in patients treated with chlorthalidone (a diuretic), amlodipine (a calcium channel blocker), lisonpril (an ACE inhibitor) or doxazosin (an alpha blocker). In the lipid lowering population the plan was to assess the all-cause mortality in those treated with either pravastatin or ‘usual care.’ The lipid lowering study had half the patients in it.
ALLHAT Trial: Blacks and Women
ALLHAT trial: 55% blacks, 45% women
In the hypertensive study, the doctor could start treatment with any of the four antihypertensive drugs. If that didn’t lower the blood pressure enough they could increase the dose, then, if that didn’t work, add in the other agents. One thing of note in this trial is that 55% of patients had to be black, and 45% women. Mainly because most clinical trials had been done in white Caucasian males, and there are racial and sex differences in treatment effects.
Why Did They Look At What They Did?
Why did they look at fatal coronary heart disease and non-fatal heart attacks rather than fatal and non-fatal heart attacks? Why did they look at all-cause mortality with statins, but not with hypertensives?
So what were the investigators trying to find out?
Two main things. Firstly, is any form of antihypertensive agent better than any other at preventing fatal CHD [coronary heart disease] and non-fatal MI [heart attacks]?
Secondly, does lipid lowering with a statin have any effect on all-cause mortality. That is, dying of anything.
A couple of questions immediately arise. Why did they use the terminology ‘fatal CHD and non-fatal MI’ in the hypertensive part of the trial? If fatal CHD is not fatal MI [myocardial infarction, that is, heart attacks], then what is it? Also, why did they choose to look at different end-points for the statin, namely all-cause mortality? Why didn’t they choose to look at all-cause mortality in the hypertensives?
Trials are always much more interesting, in my opinion, for the questions they choose not to ask, than for the questions they actually ask.
ALLHAT Trial Pulled to Bits
ALLHAT trial pulled to bits because they did NOT give the results they wanted
And, generally, the questions that the trial didn’t ask form the first point of attack on any trial — that doesn’t provide the results that people agree with. ‘Oh, well, what do you expect from ALLHAT, they didn’t look at fatal MI. Which is really important. Frankly, therefore the entire trial is a complete waste of time….. Pass the port old boy.’ In reality no trial can ever look at all end points. It’s just not logistically possible. And if the nit-pickers decide to get to work, any trial can be pulled to bits. This is exactly what is happening to the ALLHAT trial.
Why is it being pulled to bits?
Because it quite clearly did not show what people wanted it to show.
All Blood Pressure Drugs Had Similar Effect
Alpha blockers stopped because there was an INCREASE in death rates
Firstly, it showed that any form of blood pressure lowering tablet had pretty much the same effect as any other. (This trial did NOT measure the effect of placebo, so all results are one tablet verses another). In short, a diuretic was just as good as a calcium channel blocker, or an ACE-inhibitor. (Alpha blockers got pulled out of the trial early on as they showed an alarming increase in death rates).
ALLHAT Study Attacked by Drug Company-Paid Researchers
Drug Companies make much more money from ACE Inhibitors and Calcium Channel Blockers than Diuretics, so they attack the study when diuretics found just as good
So what, you might think. No surprise there. Why the attack?
Well, if I were tell you that diuretics are very cheap, have been around for years and years, and no pharmaceutical company makes any money from selling them; whereas ACE inhibitors and calcium channel blockers are much more expensive, and sell billions of dollars worth ever year….. Then you might, just might, feel that the answer could be found in this area.
Personally, I always ask the question: Is the person attacking the ALLHAT study making money from companies that make ACE-inhibitors or calcium channel blockers? If not, I take the comments very seriously. However, I have yet to identify anyone attacking the hypertensive arm of the ALLHAT study who has zero financial connections — although they can sometimes appear very tenuous.
Lipid-Lowering Part of Study
Mortality was slight HIGHER in those given Pravachol (pravastatin) than those given a placebo
And what of the lipid lowering part of the trial? What did that show?
Well, slightly to my surprise…not. The impact of pravastatin [Pravachol] on overall mortality was absolutely zero. Actually, it wasn’t exactly zero; the overall mortality was slightly higher in the pravastatin group than the group taking placebo.
How is this being explained?
“Both the pravastatin [Pravachol] and usual care groups had substantial cholesterol reductions,” said Whelton. “This is probably because many of those in the usual care group received a cholesterol-lowering drug. The magnitude of the trend toward increasing use of cholesterol-lowering drugs in usual care during the 8 years of the trial reflects the impact on clinical practice of the many positive statin trials that have taken place in those years. This trend was not fully anticipated when ALLHAT began in 1994. Thus, no difference was found between the groups in deaths and only a modest difference in the rates of heart attack and stroke.”
That quote taken from NIH website http://www.nih.gov/news/pr/dec2002/nhlbi-17.htm
Weasel Words And Non-Scientific Rubbish Dressed Up As Fact
They used weasel words and non-scientific rubbish dressed up as fact to explain why statins did not prevent a single death
For those of us who enjoy the use of weasel words and non-scientific rubbish dressed up as fact, that is a paragraph to savour. Examine the sentence that begins… ‘This is probably because….’ A perfect statement. Not based on any facts, or data, just a guess. The paragraph then goes on to state that if this guess is correct, then it explains why statins didn’t prevent a single death. (Despite the fact, of course, that LDL levels were lowered much more in the Pravastatin group).
So, all the results of a major clinical trial can be demolished by an unproven supposition based on no facts whatsoever. Yes folks, it’s science at its very best. ‘Ignore the results from the ALLHAT trial, it’s rubbish. Things that we never bothered to measure probably caused the negative results.’
Can you imagine what would happen if I said that I just ‘guessed’ that in other lipid lowering trials, people probably stopped smoking in the statin group and not in the placebo group, which explains any beneficial effects seen. Of course I didn’t bother measuring this, I just kind of guessed that it must be so. How else could you explain the benefits of statins?
I must stop now before my blood pressure gets too high and I have to start taking an ACE-inhibitor. I also seem to have got dragged off blood pressure and onto statins. I must be obsessed.
Article Previous Published on THINCS.org
This article was previously published on THINCS.org
This article was previously published on THINCS.org (The International Network of Cholesterol Skeptics).
I republished the article here with Dr. Kendrick’s permission.
Malcolm Kendrick’s Contact Info
Malcolm Kendrick, MD is the author of the wonderful, eye-opening, paradigm-shifting book book The Great Cholesterol Con: The Truth About What Really Causes Heart Disease and How to Avoid It .)
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