Professor Peter Hajek presentation from E-Cigarette Summit 2014

1. Cochrane review of efficacy of e-cigarettes for smoking cessation and harm reduction: Progress report
Peter Hajek

2. I have no links with e-cigarette (EC) manufacturers
My research into safety and effects of EC has been funded by MHRA, NIHR and UKCTAS

3. Stage of the review
The sign-off process is currently on- going
Only some preliminary data will be presented

4. Review team
Hayden McRobbie (Queen Mary University of London)
Chris Bullen (University of Auckland)
Jamie Hartmann-Boyce (University of Oxford and Cochrane Centre)
Peter Hajek (QMUL)
Review scope and methods were published early on (McRobbie et al. Cochrane Library, 14. Nov 2012, DOI: 10.1002/14651858.CD010216)

5. Cochrane Reviews
Systematic reviews of efficacy of health interventions
Meta-analytic methods combine results from randomised trials to assess treatment efficacy
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6. Interpreting forest plots
Results of individual studies
Result when they are combined
Heterogeneity

7. E-cigarette review aims
Does EC help smokers achieve long-term abstinence?
Does EC help smokers to reduce cigarette consumption by at least 50%?
Adverse effects associated with EC use
Sources of evidence
Comparisons of EC use with placebo (nicotine- free) EC; with smoking cessation medications; with other control conditions

8. Review methods
Searches: CENTRAL, MEDLINE, Embase, Cochrane trials register, references and contacts with study authors
Trials randomising smokers to EC or control condition with outcomes 6 months or longer
New field, so also cohort studies (at least 6 months f-u); and cross-over trials and follow-up studies with at least 1 week of EC use for assessment of adverse events.

9. Draft results
589 records, only a few eligible: 2 RCTs (both low risk of bias) and 6 cohort studies (varied bias risk) with 3 more studies eligible for adverse effects analysis

10. Adverse effects
There were no serious adverse events related to EC use in any study
Bullen et al. 2013:
–nicotine EC 44%; patch 45%; placebo EC 47%
Caponnetto et al. 2013
–No difference in frequency of AEs
–5 most frequent AEs: cough (26%), dry mouth (22%), shortness of breath (20%), throat irritation (17%), headache (17%).
–Frequency of AEs decreased over time, apart from throat irritation.
Cohort studies similar, mouth and throat irritation most frequent AE, dissipating over time
Longest use: 18 months

11. Three studies followed up smokers who tried EC
Grana et al 2014 - 88 smokers who used EC at least once within past 30 days but still smoked, same change in smoking at 12 M as in those not trying EC
Choi et al 2014 - Unspecified number of smokers who used EC within 30 days but still smoked, same result (11% vs 17%,NS)
Etter 2014 – 367 smokers interested in using EC answered q at 12M, 46% quit (13% of baseline sample of N=1,329)

12. 3 small studies gave smokers EC and followed them up
Polosa et al. 2011 gave EC to 40 smokers not intending to quit, 13% quit at 2 years + 27% reduced by 50% or more
Caponnetto at al 2013 gave EC to 14 smokers, with sch. not intending to quit, 14% quit at 1 year + 50% reduced
Ely 2013 gave EC to 48 smokers wanting to quit, 18 also used stop-smoking meds, 44% quit at 6 months + 27% reduced

13. Randomised trials
Caponetto et al 2013 - 300 smokers not intending to quit, EC with and without nicotine (one arm reduced EC nicotine after 6w), 12M f-u
Bullen et al. 2013 – 657 smokers wanting to quit, EC with and without nicotine or 21mg/24 patches, 6M f-u

14. Main comparisons
Effect of EC on smoking reduction and cessation
Compared to placebo (conservative)
Compared to other treatments

15. Not long to wait
The Cochrane Collaboration will release the full review within the next 2-3 weeks