Correlates of varenicline adherence among smokers with HIV and its association with smoking cessation

Introduction: With medical advances, the life expectancy of people living with HIV/AIDS (PLWHA) has improved; however, tobacco use remains a prominent risk for mortality. Although studies have examined the efficacy of varenicline for treating smoking among PLWHA, the relationship between varenicline adherence and cessation and correlates of varenicline adherence remain under-studied. Methods: We conducted secondary analyses from a randomized placebo-controlled trial of varenicline for smoking among PLWHA, using data from participants who received varenicline (N = 89). The relationship between varenicline adherence (based on pill count) and end-of-treatment smoking cessation was assessed, as were correlates of varenicline adherence. Results: Those who were abstinent took an average of 137.1 pills (SD = 39.3), or 83% of pills prescribed, vs. 105.3 pills (SD = 64.1), or 64%, for those who were smoking (OR = 1.01, 95% CI: 1.001–1.021, p = 0.03); 52/89 (58%) participants were adherent based on taking ≥80% of pills. The quit rate for adherent participants was 35% (18/52) vs. 19% (7/37) for non-adherent participants. Adherent participants were older, smoked fewer cigarettes each day, started smoking at an older age, and had lower baseline creatinine vs. non-adherent participants (p < 0.05). There was a significant time-by-group interaction effect for anxiety (F[1,72] = 6.24, p = 0.02), depression (F[1,72] = 4.2, p = 0.04), and insomnia (F[1,72] = 7.73, p = 0.007), indicating that adherent participants had less depression, anxiety, and insomnia during the initial weeks of treatment, vs. non-adherent participants. Conclusions: Our findings underscore the importance of varenicline adherence for determining cessation and highlight the role of early changes in anxiety, depression, and insomnia determining varenicline adherence.