Smoking Cessation Pharmacotherapy Efficacy in Comorbid Medical Populations: Secondary Analysis of the Evaluating Adverse Events in a Global Smoking Cessation Study (EAGLES) Randomized Clinical Trial

Introduction This study sought to compare medication efficacy in participants with medical comorbidities who smoke in the Evaluating Adverse Events in a Global Smoking Cessation Study (EAGLES) trial, a double-blind, triple-dummy, placebo- and active-controlled randomized controlled trial. Aims and Methods Participants were from the U.S. cohort of the main trial and randomized (1:1:1:1) to varenicline, bupropion, nicotine replacement therapy (NRT) patch, or placebo for 12 weeks with follow-up through week 24. Medical comorbidity data were derived from the baseline medical screening questionnaire and categorized into four subgroups (cardiac, respiratory, vascular, and diabetes). Within each comorbidity, generalized linear mixed models were used to assess the association between treatment and continuous abstinence rates from weeks 9-12 to 9-24. Similar models were used to test the effect of number of comorbidities on abstinence. Results Varenicline resulted in the highest week 12 abstinence rates across all pharmacotherapies and compared to placebo in all comorbidity subgroups: Cardiac (40.0% vs. 3.6%; odds ratios [OR] = 23.3 [5.1-107.1]), respiratory (24.7% vs. 12.8%; OR = 2.2 [1.3-3.8]), vascular (29.1% vs. 10.4%; OR = 3.6 [2.3-5.7]), and diabetes (30.9% vs. 8.3%; OR = 6.5 [2.3-19.0]). This was maintained at week 24 for those with cardiac (23.3% vs. 1.8%; OR = 21.7 [2.7-178.2]), vascular (18.9% vs. 7.1%; OR = 3.1 [1.8-5.3]), and diabetes (20.6% vs. 4.2%; OR = 8.4 [2.1-33.7]) comorbidities. Treatment contrasts within some comorbidity subgroups revealed superior efficacy of varenicline over other pharmacotherapies. All pharmacotherapies increased the odds of abstinence regardless of number of comorbidities. Conclusions Varenicline is the most efficacious option for patients with manageable cardiac, respiratory, vascular, and diabetes conditions to quit smoking, supporting recent clinical practice guidelines that recommend varenicline as first-line pharmacotherapy. Bupropion and NRT demonstrated efficacy for some comorbidity subgroups. Implications This secondary analysis of the EAGLES trial demonstrated that varenicline is the most efficacious option for patients with cardiac, respiratory, vascular, and diabetes diagnoses to quit smoking. This demonstration of varenicline efficacy among individuals with comorbid medical conditions supports recent clinical practice guidelines that recommend varenicline as a first-line pharmacotherapy for smoking cessation.