Comparative effect of varenicline and nicotine patches on preventing repeat cardiovascular events

OBJECTIVE: To determine the comparative effectiveness of postdischarge use of varenicline versus prescription nicotine replacement therapy (NRT) patches for the prevention of recurrent cardiovascular events and mortality and whether this association differs by sex. METHODS: Our cohort study used routinely collected hospital, pharmaceutical dispensing and mortality data for residents of New South Wales, Australia. We included patients hospitalised for a major cardiovascular event or procedure 2011-2017, who were dispensed varenicline or prescription NRT patches within 90day postdischarge. Exposure was defined using an approach analogous to intention to treat. Using inverse probability of treatment weighting with propensity scores to account for confounding, we estimated adjusted HRs for major cardiovascular events (MACEs), overall and by sex. We fitted an additional model with a sex-treatment interaction term to determine if treatment effects differed between males and females. RESULTS: Our cohort of 844 varenicline users (72% male, 75% <65 years) and 2446 prescription NRT patch users (67% male, 65% <65 years) were followed for a median of 2.93 years and 2.34 years, respectively. After weighting, there was no difference in risk of MACE for varenicline relative to prescription NRT patches (aHR 0.99, 95% CI 0.82 to 1.19). We found no difference (interaction p=0.098) between males (aHR 0.92, 95% CI 0.73 to 1.16) and females (aHR 1.30, 95% CI 0.92 to 1.84), although the effect among females deviated from the null. CONCLUSION: We found no difference between varenicline and prescription NRT patches in the risk of recurrent MACE. These results should be considered when determining the most appropriate choice of smoking cessation pharmacotherapy.