Dataset Information

Medication adherence and rate of nicotine metabolism are associated with response to treatment with varenicline among smokers with HIV.

ABSTRACT:

Introduction

PLWHA who smoke have shown lower cessation rates within placebo-controlled randomized trials of varenicline. Adherence and rate of nicotine metabolism may be associated with quit rates in such clinical trials.

Methods

This secondary analysis of a randomized placebo-controlled trial of varenicline for smoking among PLWHA (N = 179) examined the relationship between varenicline adherence (pill count, ≥80% of pills), nicotine metabolism (based on the nicotine metabolite ratio; NMR) and end-of-treatment smoking cessation (self-reported 7-day point prevalence abstinence, confirmed with carbon monoxide of ≤ 8 ppm, at the end of treatment; EOT).

Results

Combining varenicline and placebo arms, greater adherence (OR = 1.011, 95% CI:1.00-1.02, p = 0.051) and faster nicotine metabolism (OR = 3.08, 95% CI:1.01-9.37, p = 0.047) were related to higher quit rates. In separate models, adherence (OR = 1.009, 95% CI:1.004-1.01, p < 0.001) and nicotine metabolism rate (OR = 2.04, 95% CI:1.19-3.49, p = 0.009) interacted with treatment arm to effect quit rates. The quit rate for varenicline vs. placebo was higher for both non-adherent (19% vs. 5%; χ²[1] = 2.80, p = 0.09) and adherent (35% vs. 15%; χ²[1] = 6.51, p = 0.01) participants, but the difference between treatment arms was statistically significant only for adherent participants. Likewise, among slow metabolizers (NMR < 0.31), the varenicline quit rate was not significantly higher vs. placebo (14% vs. 5%; χ²[1] = 1.17, p = 0.28) but, among fast metabolizers (NMR ≥ 0.31), the quit rate for varenicline was significantly higher vs. placebo (33% vs. 14%; χ²[1] = 4.43, p = 0.04).

Conclusions

Increasing varenicline adherence and ensuring that fast nicotine metabolizers receive varenicline may increase quit rates for PLWHA.

SUBMITTER: Bauer AM

PROVIDER: S-EPMC7572610 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:IntroductionSmokers who use opioids smoke more cigarettes per day (CPD) than non-opioid users, which could be due to the effects of opioids on nicotine metabolism. Moreover, nicotine metabolism increases during pregnancy, potentially making quitting more difficult for pregnant smokers. We examined nicotine metabolism and its association with opioid use (OU) and CPD in pregnant smokers.MethodsWe recruited pregnant women who smoked at least 5 CPD for a clinical trial of smoking cessation. Plasma nicotine metabolite ratio (NMR; trans-3'-hydroxycotinine (3HC)/cotinine)-a biomarker of nicotine metabolism-OU (involving methadone, buprenorphine, fentanyl, oxycodone, or tramadol), and CPD were assessed at baseline. We used linear regression to examine the associations between log-transformed NMR, OU, and CPD, adjusting for race/ethnicity and menthol smoking.ResultsAmong 129 pregnant smokers, 25 (19%) were opioid users; most were maintained on methadone (n = 14). Compared to non-OU smokers, OU smokers had higher median CPD (10.0 vs. 7.0, p = .0007), serum 3HC (81.0 vs. 42.0 ng/mL, p = .0001), and NMR (0.63 vs. 0.43, p < .0001). In addition, methadone-maintained smokers had a higher median NMR than non-OU smokers (0.66 vs. 0.43, p = .0004). Adjusting for covariates, log-transformed NMR was greater in OU smokers (p = .012), specifically methadone-maintained smokers (p = .024), than non-OU smokers.ConclusionsOur preliminary results show that OU is associated with a higher NMR in pregnant smokers. A larger study sample is needed to replicate this finding, examine potential mechanisms, and determine its clinical significance.ImplicationsAmong pregnant smokers, we observed that nicotine metabolism was significantly faster among opioid users-the majority of whom were on methadone maintenance-compared to nonusers, which could have implications for smoking cessation. Further studies are needed to replicate this finding, evaluate potential mechanisms, and determine its clinical significance.