Tobacco smoking as a risk factor of active tuberculosis in HIV-infected patients

<b>Background:</b> Despite the measures taken, tuberculosis (TB) is still a leading cause of mortality among persons living with HIV in Russian Federation. At the same time, it is known that tobacco smoking among HIV patients is more common than in the general population. Aim of the study is to investigate the effect of smoking on the risk of active tuberculosis in patients with HIV infection. <b>Methods:</b> In a case-control study we investigated 171 patients: 85 people in the HIV group, 86 people in the HIV/tuberculosis group. The tobacco dependence was diagnosed according to the criteria of the WHO. The smoking index calculated as the number of cigarettes smoked per day multiplied by years smoked and divided by 20. Information on close TB contact, past incarceration, CD4 cell count was obtained from original medical records. <b>Results:</b> 128 (75%) patients smoked cigarettes, and 126 (98%) of them were tobacco addicted. A smoking index value of more than 10 was associated with significantly higher risk of active TB in smoking patients: OR = 5.7; 95% CI [2.32-17.11] p&lt;0.001. In a multivariate analysis, the tobacco smoking (OR = 6.9; 95% CI [2.1-22.2], p = 0.001), close TB contact (OR = 5.2; 95% CI [1.4–18.5], p=0.012), past incarceration (OR=5.2; 95 % CI [1.5–17.7], p=0.009), CD4 count less than 200 cells/µl (OR=5.8; 95% CI [2.1–16.0], p&lt;0.001) were independently associated with active TB. <b>Conclusion:</b> We describe an independent association between tobacco smoking and active TB in people living with HIV. Given the high prevalence of tobacco smoking among HIV-infected patients, it is important to inform patients about the risks of smoking and treat tobacco dependence.