Varenicline and Nicotine Replacement Therapy for Smokers Admitted to Hospitals: A Randomized Clinical Trial.

Importance: Varenicline is the most effective sole pharmacotherapy for smoking cessation. If used in combination with nicotine replacement therapy (NRT), cessation rates may be further improved, but the efficacy and safety of the combination need to be evaluated.

Objective: To examine whether hospitalized smokers treated with varenicline and NRT lozenges achieve higher prolonged smoking abstinence rates compared with those treated with varenicline alone.

Design, Setting, And Participants: A double-blind, placebo-controlled randomized clinical trial was conducted in adult medical or surgical inpatients of 5 Australian public hospitals with a history of smoking 10 cigarettes or more per day, interested in quitting, and available for 12-month follow-up between May 1, 2019, and May 1, 2021 (final 12-month data collection in May 2022). Data analysis was performed from June 1 to August 30, 2023.

Interventions: A 12-week varenicline regimen was initiated during hospitalization at standard doses in all participants. Participants were randomized to additionally use NRT (2 mg) or placebo lozenges if there was an urge to smoke. Behavioral support (Quitline) was offered to all participants.

Main Outcomes And Measures: The primary outcome was biochemically verified sustained abstinence at 6 months. Secondary outcomes included self-reported prolonged abstinence, 7-day point prevalence abstinence (3, 6, and 12 months), and medicine-related adverse events.

Results: A total of 320 participants (mean [SD] age, 52.5 [12.1] years; 183 [57.2%] male) were randomized. The conduct of biochemical verification was affected by COVID-19 restrictions; consequently, the biochemically verified abstinence in the intervention vs control arms (18 [11.4%] vs 16 [10.1%]; odds ratio [OR], 1.14; 95% CI, 0.56-2.33) did not support the combination therapy. The secondary outcomes in the intervention vs control arms of 7-day point prevalence abstinence at 6 months (54 [34.2%] vs 37 [23.4%]; OR, 1.71; 95% CI, 1.04-2.80), prolonged abstinence at 12 months (47 [29.9%] vs 30 [19.1%]; OR, 1.77; 95% CI, 1.05-3.00), and 7-day point prevalence abstinence at 12-months (48 [30.6%] vs 31 [19.7%]; OR, 1.79; 95% CI, 1.07-2.99) significantly improved with the combination therapy. The self-reported 6-month prolonged abstinence (61 [38.6%] vs 47 [29.7%]; OR, 1.49; 95% CI, 0.93-2.39) favored the combination therapy but was not statistically significant. Medicine-related adverse events were similar in the 2 groups (102 [74.5%] in the intervention group vs 86 [68.3%] in the control group).

Conclusions And Relevance: In this randomized clinical trial of the combination of varenicline and NRT lozenges in hospitalized adult daily smokers, the combination treatment improved self-reported abstinence compared with varenicline alone, without compromising safety, but it did not improve biochemically validated abstinence.

Trial Registration: anzctr.org.au Identifier: ACTRN12618001792213.