Thursday, November 03, 2011

Bias Against Cold Turkey Quitting is Apparent in Literature; Possibly Influenced by Financial Conflicts of Interest?

Imagine that you were doing a study on whether nicotine replacement therapy (NRT) is more effective than cold turkey quitting in smoking cessation. You ask a bunch of successful quitters (ex-smokers) and unsuccessful quitters (current smokers who have made a quit attempt) what strategy for smoking cessation they used in their most recent quit attempt. You might structure the question something like this:

During your last quit attempt, what was the primary method you used to try to quit?
1. NRT
2. Buproprion
3. Chantix
4. Cold Turkey
5. Other

In comparing the effectiveness of each approach, you might compare the reported use of each strategy between successful and unsuccessful quitters.

Suppose, instead, that you had a vested interest, or a bias towards not finding that cold turkey approaches are superior to NRT. What might you do?

A clever approach would be to simply not list "cold turkey" as a potential answer. Instead, you might provide a very long list of potential smoking cessation aids, including books, web sites, group sessions, phone lines, group sessions, etc. Let the respondent check off all the strategies that they used. Then, at the end of the long list, include a category entitled "Nothing." This category would only apply to people who not only tried to quit unaided by medication, but who also failed to even look at a smoking cessation web site, make a phone call, watch a video, attend a group session, etc. This doesn't sound like a very motivated group of smokers, does it?

What happens if you then use this category to classify smokers as "unaided" quitters (a very loose and inaccurate proxy for cold turkey quitters)?

My guess is that you are going to get an artificially low estimate of the cessation rate for cold turkey quitters. Rather than a direct comparison of cold turkey quitting vs. the use of NRT, this provides a comparison of NRT against a loosely defined group of people who don't appear to have been very motivated to quit in the first place.

Unfortunately, this appears to be the method used to ascertain the quit strategies used by smokers in the Smoking Toolkit Study, a series of monthly annual surveys in the UK which are designed to examine smoking cessation and the effectiveness of various cessation strategies.

The actual question that appears in the February 2010 questionnaire is as follows:

"Which, if any, of the following did you try to help you stop smoking during the most recent serious quit attempt?" (Please code all that apply)

"Nicotine replacement product (eg. patches/gum/inhaler) without a prescription
Nicotine replacement product on prescription or given to you by a health professional
Zyban (bupropion)
Champix (varenicline)
Attended an NHS Stop Smoking group
Attended a non-NHS smoking support group Attended one or more NHS Stop Smoking one-to-one counselling/advice/support session/s
Attended a non-NHS one-to-one counselling/advice/support session/s
Phoned NHS Smoking Helpline
Phoned a non- NHS Smoking Helpline Allen Carr Easyway session
Allen Carr Easyway book
Another book or booklet
Visited www.nhs.uk/smokefree website
Visited a website other than Smokefree
Hypnotherapy
Acupuncture
Don't Know
Nothing
Other"

Despite this bias against cold turkey quitting, the results of a recent report from the study found that NRT was no more effective than "unaided quitting." This almost assuredly indicates that had cold turkey been pitted against NRT, it would have won hands down.

Why this tremendous bias in what is supposed to be objective scientific research?

The Rest of the Story

Perhaps the apparent bias is less astonishing when one finds out the rest of the story: The study was funded by the pharmaceutical industry.

According to a background study document: "The Smoking Toolkit Study is currently funded
by Cancer Research UK, Pfizer and GSK [GlaxoSmithKline]."

Moreover, two of the researchers working on the Smoking Toolkit Study also have financial conflicts of interest with Big Pharma.

As disclosed in a recent paper: "RW undertakes research and consultancy for the following developers and manufacturers of smoking cessation treatments; Pfizer, J&J, McNeil, GSK, Nabi, Novartis and Sanofi-Aventis. RW also has a share in the patent of a novel nicotine delivery device. AMC has received travel funding, honorariums and consultancy payments from manufacturers of smoking cessation products (Pfizer, J&J, McNeil, GSK, Nabi, Novartis and Sanofi-Aventis). He also receives payment for providing training to smoking cessation specialists; receives royalties from books on smoking cessation and has a share in a patent of a nicotine delivery device."

That paper also acknowledges that the Smoking Toolkit Study is funded by: "Pfizer, GlaxoSmithKline and Johnson and Johnson."

Perhaps worst of all, in the recent paper that reports the results of the Smoking Toolkit Study, the author (RW above) fails to disclose any financial conflicts of interest and the report fails to disclose that the study is funded by several pharmaceutical companies.

The rest of the story is that there does indeed appear to be a bias in favor of pharmaceutical smoking cessation aids, and there is at least the appearance that this bias is at least in part related to the receipt of money from pharmaceutical companies.


(Thanks to John Polito for the tip.)

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