Background:  Rates of tobacco smoking in HIV-infected individuals are very high across most populations. Despite evidence of increased risk of cardiovascular disease (CVD), the majority of HIV-infected smokers are unable to stop smoking. In non-HIV infected individuals there is a substantial reduction in coronary heart disease within one to 2 years of stopping smoking. The objective of this analysis is to estimate the rates of CVD events after stopping smoking in patients with HIV-infection.

Methods:  Patients were included in this analysis if they reported smoking status, and no prior CVD before enrolment into D:A:D. In D:A:D, smoking status is collected at each visit as current smoker (yes/no) and ever smoker (yes/no). Duration of stopping smoking was calculated for persons who had reported current smoking during follow-up and no current smoking subsequently. Endpoints were: myocardial infarction (MI); coronary heart disease (CHD) (MI plus invasive coronary artery procedure or death from other coronary heart disease); CVD disease (CHD plus carotid artery endarterectomy or stroke); and all cause mortality. Event rates were calculated for never smokers, ex-smokers at D:A:D study entry, current smokers, and smokers who stopped during D:A:D follow-up. Incidence rate ratios (IRR) were determined using Poisson regression  adjusted for age, sex, cohort, calendar year, antiretroviral treatment, family history of CVD, diabetes (men and women), and time updated lipids and blood pressure assessments

Results:  In this study, 27 586 patients had their smoking status reported up to 1 February 2008. In total there were 432, 600, 746 and 1902 MI, CHD, CVD and mortality events respectively; crude event rates were 2.85, 3.96, 4.94, and 12.45 per 1000 person years respectively. Results for CVD are summarised in the Table. After adjustment for other covariates, the IRR of CVD in patients who stopped smoking during follow-up decreased from 2.32 within the first year of stopping to 1.49 after 3+ years since stopping smoking compared to those never smoked. Similar trends were observed for the MI and CHD endpoints, but reductions in risk were less pronounced for all cause mortality. 

Conclusions:  The risk of CVD events in HIV-infected patients decreased with increasing time since stopping smoking. Smoking cessation efforts should be a priority in the management of HIV-infected individuals.