Medicines help smokers quit long term, finds Cochrane overview of reviews

Key message: Varenicline, nicotine replacement therapy and bupropion all improve smokers’ chances of quitting long term, with a low risk of harms

Today is World No Tobacco Day, which seems a great day for the publication of new Cochrane evidence on medicines to help people quit smoking. Three medicines are licensed for this purpose in Europe and the USA and recommended in many national guidelines: nicotine replacement therapy (NRT), bupropion and varenicline. Cytisine is licensed in Russia and some other countries and other medicines, such as nortriptyline, have been tested. A new overview of reviews from a team at the Cochrane Tobacco Addiction Group has brought together results from Cochrane reviews on the effectiveness of medicines for helping adults to quit smoking for at least six months and on harms associated with them. It looks at how these medicines compare with each other and with placebo (dummy medicine). Twelve reviews were included, with over 101,000 smokers from 267 randomised controlled trials.

What did they find?

• Varenicline, NRT and bupropion all improve chances of quitting compared to placebo
• Varenicline was more effective than bupropion and single forms of NRT, such as nicotine patch or gum
• Combination NRT was as effective as varenicline and more effective than single forms of NRT
• Bupropion and NRT were equally effective
• Different forms of NRT were generally comparable though gum was slightly less effective than inhalers, sprays, tablets or lozenges
• Cytisine and nortriptyline increased the chance of quitting
• None of the treatments were associated with an increase in harmful effects (but see below)

How good is the evidence?

• This draws on a large body of evidence, combining results from twelve Cochrane reviews. For NRT, bupropion and varenicline the reviewers conducted a network meta-analysis using study level data; otherwise the existing analyses were used
• The quality of the included reviews is considered to be high but that of the trials within the reviews is variable. The highest quality was seen in trials of the newest medicine, varenicline (with 81% at low risk of bias for their randomisation procedures)
• In most trials, smoking status was checked by testing breath, blood or urine, which is more reliable than going by whether people say they have stopped smoking
• The reviewers note that data on serious adverse effects may have been under-reported, especially in older trials, so safety findings may not be as reliable as those on effectiveness

So what does this mean for the smoker who wants to quit?

These medicines can really improve the chances of quitting successfully. For every 10 people who quit with a dummy medicine, about 18 could be expected to quit using NRT or bupropion and 28 with varenicline. Varenicline also helped about double the number or people quit than NRT (and even more than that for those using nicotine gum).

There’s also evidence from Cochrane reviews that combining medicine with behavioural suppport can increase the chance of quitting even more, with more intensive support being the most effective . You can read blogs about these reviews from the Lifestyle Elf via the links below.

What next?

The reviewers conclude that the efficacy of NRT, bupropion and varenicline is well established across a strong evidence base, but that uncertainties remain about the safety of varenicline and research should continue to evaluate this.

In a press release, lead reviewer Kate Cahill, from the Department of Primary Care Health Services at the University of Oxford, noted that this overview not only provides “strong evidence” that varenicline, bupropion and NRT help people stop smoking but also that “although cytisine is not currently licensed for smoking cessation in most of the world, these data suggest it has potential as an effective and affordable therapy”.

Plenty of encouraging news for smokers, then, on World Tobacco Day, which will also be welcomed by those engaged in helping people quit.

Links:

Cahill K, Stevens S, Perera R, Lancaster T. Pharmacological interventions for smoking cessation: an overview and network meta-analysis. Cochrane Database of Systematic Reviews 2013, Issue 5. Art. No.: CD009329. DOI: 10.1002/14651858.CD009329.pub2.

The Lifestyle Elf blog http://www.thelifestyleelf.net/cochrane-review-finds-combining-medication-with-behavioural-support-helps-smokers-quit/ on the review below

Stead  LF, Lancaster  T. Combined pharmacotherapy and behavioural interventions for smoking cessation. Cochrane Database of Systematic Reviews  2012, Issue 10. Art. No.: CD008286. DOI: 10.1002/14651858.CD008286.pub2.

The Lifestyle elf blog http://www.thelifestyleelf.net/more-intensive-behavioural-support-means-more-smokers-successfully-quit-finds-new-cochrane-review/ on the review below

Stead LF, Lancaster T. Behavioural interventions as adjuncts to pharmacotherapy for smoking cessation. Cochrane Database of Systematic Reviews 2012, Issue 12. Art. No.: CD009670. DOI: 10.1002/14651858.CD009670.pub2.