Thursday, 23 May 2013

Prevention vs Cure, quackery, bias and conflict of interest.

I believe in the maxim "Prevention is better than cure".
Image from www.nationalarchives.gov.uk

Some definitions:

Prevention. Cure. Quackery. Bias. Conflict of interest. Logical fallacies. In the case of the maxim, prevention means hindrance, as it's impossible to 100% stop illness from occurring. To someone who already has an illness, the maxim is obviously moot!

Quackery:

I have been accused of quackery. Despite having provided evidence to refute the claim, the person has refused to retract the accusation or provide proper evidence (other than Logical fallacies) to support it. EDIT: I blocked the person on Twitter. I am no longer on that person's quackery list.

Bias:

A long time ago, I mentioned a study Intensive lipid lowering with atorvastatin in patients with stable coronary disease.

"RESULTS: The mean LDL cholesterol levels were 77 mg per deciliter (2.0 mmol per liter) during treatment with 80 mg of atorvastatin and 101 mg per deciliter (2.6 mmol per liter) during treatment with 10 mg of atorvastatin. The incidence of persistent elevations in liver aminotransferase levels was 0.2 percent in the group given 10 mg of atorvastatin and 1.2 percent in the group given 80 mg of atorvastatin (P&lt:0.001). A primary event occurred in 434 patients (8.7 percent) receiving 80 mg of atorvastatin, as compared with 548 patients (10.9 percent) receiving 10 mg of atorvastatin, representing an absolute reduction in the rate of major cardiovascular events of 2.2 percent and a 22 percent relative reduction in risk (hazard ratio, 0.78; 95 percent confidence interval, 0.69 to 0.89; P&lt:0.001). There was no difference between the two treatment groups in overall mortality."

"CONCLUSIONS: Intensive lipid-lowering therapy with 80 mg of atorvastatin per day in patients with stable CHD provides significant clinical benefit beyond that afforded by treatment with 10 mg of atorvastatin per day. This occurred with a greater incidence of elevated aminotransferase levels."

Unfortunately, the statement "There was no difference between the two treatment groups in overall mortality." is incorrect. According to the full study (hidden behind a pay-wall) there were 26 more deaths in the 80mg/day group than in the 10mg/day group. That's not statistically significant, as the group sizes were ~5,000 each. However, the statement didn't mention statistical significance.

Therefore, the statement "Intensive lipid-lowering therapy with 80 mg of atorvastatin per day in patients with stable CHD provides significant clinical benefit beyond that afforded by treatment with 10 mg of atorvastatin per day." is also incorrect. Dying is worse than having major cardiovascular events (heart attacks & strokes), which are survivable.

Why is there a disparity between the publicly-viewable abstract, the full study and reality? From the full study:-

"Funding for the study was provided by Pfizer Inc., New York, New York. Dr. Shepherd has received consulting fees from AstraZeneca, GlaxoSmithKline, Merck, Oxford Biosensors, Pfizer Inc., and Schering-Plough, and lecture fees from AstraZeneca, Merck, and Schering-Plough. Dr. Kastelein has received consulting fees and lecture fees from Pfizer Inc., AstraZeneca, Merck, and Schering-Plough, and grant support from Pfizer Inc. and AstraZeneca. Dr. Bittner has received consulting fees from CV Therapeutics, Novartis, Pfizer Inc., Abbott, and Reliant, and grant support from Pfizer Inc., Atherogenics, Merck, Kos Pharmaceuticals, Abbott, CV Therapeutics, and the National Institutes of Health. Dr. Deedwania has received consulting fees and lecture fees from Pfizer Inc. and AstraZeneca. Dr. Breazna, Dr. Wilson, and Dr. Zuckerman are all employees of Pfizer Inc. Mr. Dobson is an employee of Envision Pharma Ltd., which was a paid consultant to Pfizer Inc. in connection with the development of the manuscript. Dr. Wenger has received consulting fees from CV Therapeutics, Sanofi-Aventis, Schering-Plough, AstraZeneca, Abbott, Merck, and Pfizer Inc., and grant support from Pfizer Inc., Merck, and the National Heart, Lung, and Blood Institute."

Atorvastatin is manufactured by Pfizer Inc.

Conflict of interest:

I like the article Is Vitamin D Shooting Me in the Foot?, because Dr. Ken D. Berry prescribes his patients an effective dose of Vitamin D3, even though it results in him losing money due to the drastic reduction in the number of benign skin cancers for him to freeze-off. Now, that's what I call integrity!

Can a breast cancer surgeon (who receives payment for curing breast cancer using surgery) give a truly impartial opinion on other cancer cures, or cancer prevention? Does he always clearly state his competing interest? I think not!

2 comments:

Nigel Kinbrum said...

I only just saw your comment. For some reason, I didn't get a notification email. Disqus has up & down voting for comments. See the ^ & v symbols.

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