Role of e-cigarettes and pharmacotherapy during attempts to quit cigarette smoking: The PATH Study 2013-16

Abstract

Background: More smokers report using e-cigarettes to help them quit than FDA-approved pharmacotherapy.

Objective: To assess the association of e-cigarettes with future abstinence from cigarette and tobacco use.

Design: Cohort study of US sample, with annual follow-up.

Participants: US adult (ages 18+) daily cigarette smokers identified at Wave 1 (W1; 2013-14) of the PATH Study, who reported a quit attempt before W2 and completed W3 (n = 2443).

Exposures: Use of e-cigarettes, pharmacotherapy (including nicotine replacement therapy), or no product for last quit attempt (LQA), and current daily e-cigarette use at W2.

Analysis: Propensity score matching (PSM) of groups using different methods to quit.

Outcome measures: 12+ months abstinence at W3 from cigarettes and from all tobacco (including e-cigarettes). 30+ days abstinence at W3 was a secondary outcome.

Results: Among daily smokers with an LQA, 23.5% used e-cigarettes, 19.3% used pharmacotherapy only (including NRT) and 57.2% used no product. Cigarette abstinence for 12+ months at W3 was ~10% in each group. Half of the cigarette abstainers in the e-cigarette group were using e-cigarettes at W3. Different methods to help quitting had statistically comparable 12+ month cigarette abstinence at W3 (e-cigarettes vs no product: Risk Difference (RD) = 0.01, 95% CI: -0.04 to 0.06; e-cigarettes vs pharmacotherapy: RD = 0.02, 95% CI:-0.04 to 0.09). Likewise, daily e-cigarette users at W2 did not show a cessation benefit over comparable no-e-cigarette users and this finding was robust to sensitivity analyses. Abstinence for 30+ days at W3 was also similar across products.

Limitations: The frequency of e-cigarette use during the LQA was not assessed, nor was it possible to assess continuous abstinence from the LQA.

Conclusion: Among US daily smokers who quit cigarettes in 2014-15, use of e-cigarettes in that attempt compared to approved cessation aids or no products showed similar abstinence rates 1-2 years later.

Fig 1. Data collection schema to investigate the role of e-cigarettes and pharmacotherapy during attempts to quit cigarette smoking in the PATH Study.

Fig 2. Net risk difference^a between matched samples of e-cigarette users and comparison groups in cigarette abstinence for 12+ months at W3.

^aRisk difference is the difference between the risk of an outcome in the exposed group and the unexposed group. Confidence intervals in this figure are Bonferroni adjusted to account for the 10 different comparisons that were undertaken in Fig 2 and Fig 3. For example, this adjustment means that the CIs for the e-cigarette vs no e-cigarette comparison in Fig 2 changed from -0.02 to 0.05. to a more conservative -0.03 to 0.07.

Fig 3. Net risk difference^a between matched samples of e-cigarette users and comparison groups in cigarette abstinence for 30+ days at W3.

^aRisk difference is the difference between the risk of an outcome in the exposed group and the unexposed group. Confidence intervals in this figure are adjusted to account for the 10 different comparisons that were undertaken in Fig 2 and Fig 3. For example, this adjustment meant that the CIs for the e-cigarette vs no e-cigarette comparison in Fig 3 changed from -0.02, 0.07 to a more conservative -0.03 to 0.09.

Fig 4. Net risk difference^a between matched samples of e-cigarette users and comparison groups in tobacco abstinence (including e-cigarettes) for 12+ months at W3.

^aRisk difference is the difference between the risk of an outcome in the exposed group and the unexposed group. Confidence intervals in this figure are Bonferroni adjusted to account for the 3 different comparisons that were undertaken in Fig 4. For example, this adjustment meant that the CIs for the e-cigarette vs no e-cigarette comparison in Fig 4 changed from -0.05 to -0.004 to a more conservative -0.06 to 0.00.