Factors associated with the efficacy of smoking cessation treatments and predictors of smoking abstinence in EAGLES

Addiction. 2018 Aug;113(8):1507-1516. doi: 10.1111/add.14208. Epub 2018 Mar 30.

Abstract

Aims: To assess (1) how far the efficacies of front-line smoking cessation pharmacotherapies vary as a function of smoker characteristics and (2) associations between these characteristics and success of smoking cessation attempts.

Design: Prospective correlational study in the context of a double-blind randomized trial. The outcome was regressed individually onto each covariate after adjusting for treatment, and then a forward stepwise model constructed. Treatment moderator effects of covariates were tested by treatment × covariate interactions.

Setting: Health service facilities in multiple countries.

Participants: Data came from 8120 smokers willing to make a quit attempt, randomized to varenicline, bupropion, nicotine replacement therapy (NRT) or placebo in Evaluating Adverse Events in a Global Smoking Cessation Study (EAGLES) between 30 November 2011 and 13 January 2015.

Measurements: Smoker characteristics measured at baseline were country, psychiatric history, sex, age, body mass index (BMI), ethnic group, life-time suicidal ideation/behaviour, anxiety, depression, aggression, psychotropic medication, history of alcohol/substance use disorder, age of starting smoking, cigarette dependence [Fagerström Test for Cigarette Dependence (FTCD)] and prior use of study medicines. Outcome was biochemically confirmed continuous abstinence at weeks 9-24 from start of treatment.

Findings: No statistically significant treatment × covariate interactions were found. Odds of success were associated independently positively with age [odds ratio (OR) = 1.01; 95% confidence interval (CI) = 1.00, 1.01], BMI (1.01; 95% CI = 1.00, 1.02) and age of starting smoking (1.03; 95% CI = 1.02, 1.04). Odds were associated independently negatively with US (versus non-US) study site (0.53; 95% CI = 0.46, 0.61), black (versus white) ethnic group (0.57; 95% CI = 0.45, 0.72), mood disorder (0.85; 95% CI = 0.73, 0.99), anxiety disorder (0.71; 95% CI = 0.55, 0.90) and psychotic disorder (0.73; 95% CI = 0.50, 1.07), taking psychotropic medication (0.81; 95% CI = 0.68, 0.95), FTCD (0.89; 95% CI = 0.87, 0.92) and previous use of NRT (0.78; 95% CI = 0.67, 0.91).

Conclusions: While a range of smoker characteristics-including psychiatric history, cigarette dependence and prior use of nicotine replacement therapy (NRT)-are associated with lower cessation rates, they do not substantially influence the efficacy of varenicline, bupropion or NRT.

Trial registration: ClinicalTrials.gov NCT01456936.

Keywords: Bupropion; nicotine replacement therapy; placebo; smoking cessation; treatment effects; varenicline.

Publication types

  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Age Factors
  • Anxiety Disorders / drug therapy
  • Anxiety Disorders / epidemiology
  • Bupropion / therapeutic use
  • Double-Blind Method
  • Ethnic Groups
  • Female
  • Humans
  • International Cooperation
  • Male
  • Middle Aged
  • Mood Disorders / drug therapy
  • Mood Disorders / epidemiology
  • Prognosis
  • Psychotic Disorders / drug therapy
  • Psychotic Disorders / epidemiology
  • Psychotropic Drugs / therapeutic use
  • Smoking / epidemiology
  • Smoking / therapy*
  • Smoking Cessation Agents / therapeutic use*
  • Smoking Cessation*
  • Tobacco Use Cessation Devices*
  • Treatment Outcome
  • United States
  • Varenicline / therapeutic use

Substances

  • Psychotropic Drugs
  • Smoking Cessation Agents
  • Bupropion
  • Varenicline

Associated data

  • ClinicalTrials.gov/NCT01456936