Updated advice to physicians on how to treat tobacco addiction.

For decades now, smokers have been encouraged to "ask their doctors" for help in quitting smoking. And for almost as long, doctors have been encouraged to "ask, advise, assist" their patients who smoke to take steps towards quitting.

But what advice should doctors give? And has that advice changed in response to the marketing of e-cigarettes?

This post reports on the evolving advice given to Canadian physicians.

Can-Adaptt and beyond ... 

A decade ago, Health Canada funded the development of guidelines through CAN-ADAPTT. These guidelines, published in 2012, were coordinated through the Center for Addictions and Mental Health, and lead by Dr. Peter Selby, and remain available in a variety of user-friendly forms, and provide advice for specific populations.

A decade on, a review and update of these guidelines would be expected. One of the groups that is working on an update is the Canadian Task Force on Preventive Health Care (formerly known as the Canadian Task Force on Periodic Health Examination). This body was created by the federal government and currently operates with the support of the Public Health Agency of Canada. `

For the past 5 years, this task force has been reviewing guidelines for treating Tobacco Smoking in Adults, and 4 years have passed since it  published the protocol for its evidence review. It was anticipated that this review would be done in two stages: the first on existing stop smoking interventions, and the "second stage will involve updating a systematic review on electronic cigarettes." The finalization of this review has been delayed, and is now slated for "2022/2023". 

Meanwhile, Dr. Selby and his CAMH colleague Dr. Zawertailo produced an independent review of the evidence and update of advice to practitioners. 

Last week their results were published in an article "Tobacco Addiction" published last week in the New England Journal of Medicine (access is free, but requires registration). Their review focuses on the effectiveness of well-known therapies (counselling, nicotine replacement, verenicline and burpoprion), while also touching on "second-line" agents like nortriptyline, clonidine or more recently-tested drugs like psilocybin.

The evolution of advice on the effectiveness of vaping to quit.  

This is the first scientific reviews by a leading Canadian expert in smoking cessation since e-cigarettes have been legalized for sale in Canada. 

It is the first published Canadian review since 2018, when Health Canada began to gently encourage smokers to see e-cigarettes as "linked to improved rates of success" in quitting. (Concerns were raised about this advice in the departmental evaluation of the program, and there are plans to update the web-site by the end of this month). 

Practitioners and smokers in Canada continue to get equivocal advice on whether or not e-cigarettes are helpful in quitting. CAMH, for example, counsels that "using e-cigarettes is NOT a proven strategy to help you quit smoking." On the other hand, the Lower-Risk Nicotine Use Guidelines (which were developed with CAMH) recommend that "E-cigarettes with nicotine may be an effective cessation aid for people who use combustible tobacco."

In the NEJM review, Drs. Selby and Zawertailo were unequivocal in their conclusions on this point: "We would recommend against the use of e-cigarettes for smoking cessation given insufficient evidence to support their use." Instead, they recommend that physicians support their patients' quitting attempts by using prescription medications as a first-line treatment, either alone or in combination with  NRT. They recommend that these quit attempts also be supported by counselling and follow-up. 

These conclusions are in line with those published last year by the US Preventive Services Task Force, and the previous year by the U.S. Surgeon General (2020),

Changing products force greater uncertainty

Drs. Selby and Zawertailo identify the "areas of uncertainty" that have cast doubt on previous research findings on e-cigarettes. While there has been "moderate-certainty evidence that nicotine e-cigarettes are more effective than nicotine-replacement therapy" .. the  "trials [which] have involved e-cigarettes that are no longer on the market, and study of newer e-cigarette types (e.g., nicotine salt-pod devices) is warranted."

The same issues were discussed in greater length during a  review conducted for the Australian government and published this spring. This review explained why the results of a few clinical trials with older products do not provide relevant evidence for the use of much-changed devices and liquids.

• There is limited evidence that, in the clinical context, freebase nicotine e-cigarettes may be more efficacious for smoking cessation than existing NRT, and that nicotine e-cigarettes may be more efficacious than no intervention or usual care. 
• Trials demonstrating efficacy were limited to products with freebase nicotine concentrations ≤20mg/mL. There is no evidence that nicotine salt products are efficacious for smoking cessation. 
• There is insufficient evidence that freebase nicotine e-cigarettes are efficacious for smoking cessation, compared to non-nicotine e-cigarettes or that non-nicotine e-cigarettes are efficacious for smoking cessation compared to counselling or approved NRT. 
• There is insufficient evidence that freebase nicotine e-cigarettes are efficacious outside the clinical setting. 
• No evidence on nicotine salt products was located and their efficacy for smoking cessation is unknown. 
• There is limited evidence that use of nicotine e-cigarettes for smoking cessation results in greater ongoing exposure to nicotine than approved NRT, through ongoing exclusive e-cigarette use or dual use if smoking continues