Pneumonia in HIV-infected persons: increased risk with cigarette smoking and treatment interruption

Abstract

Rationale: Bacterial pneumonia is a major cause of morbidity for HIV-infected persons and contributes to excess mortality in this population.

Objectives: To evaluate the frequency and risk factors for occurrence of bacterial pneumonia in the present era of potent antiretroviral therapy.

Methods: We evaluated data from a randomized trial of episodic antiretroviral therapy. The study, Strategies for Management of Antiretroviral Therapy, enrolled 5,472 participants at 318 sites in 33 countries. Study patients had more than 350 CD4 cells at baseline. Diagnosis of bacterial pneumonia was confirmed by a blinded clinical-events committee.

Measurements and main results: During a mean follow-up of 16 months, 116 participants (2.2%) developed at least one episode of bacterial pneumonia. Patients randomized to receive episodic antiretroviral therapy were significantly more likely to develop pneumonia than patients randomized to receive continuous antiretroviral therapy (hazard ratio, 1.55; 95% confidence interval, 1.07-2.25; P = 0.02). Cigarette smoking was a major risk factor: Current-smokers had more than an 80% higher risk of pneumonia compared with never-smokers (hazard ratio, 1.82; 95% confidence interval, 1.09-3.04; P = 0.02). Participants who were on continuous HIV treatment and were current smokers were three times more likely to develop bacterial pneumonia than nonsmokers. Current smoking status was significant, but a past history of smoking was not.

Conclusions: Bacterial pneumonia is a major source of morbidity, even for persons on potent antiretroviral therapy, including those with high CD4 cells. Efforts to reduce this illness should stress the importance of uninterrupted antiretroviral therapy and attainment and/or maintenance of nonsmoking status.

Trial registration: ClinicalTrials.gov NCT00027352.

Figure 1.

Kaplan-Meier curves for time to first episode of bacterial pneumonia. The solid line represents the viral suppression (VS) group; the dashed line represents the drug conservation (DC) group. The overall hazard ratio of events (DC/VS) was 1.55 (95% confidence interval, 1.07–2.25; P = 0.02).

Figure 2.

Estimated unadjusted and adjusted hazard ratios—drug conservation (DC) versus viral suppression (VS)—for first occurrence of bacterial pneumonia. The vertical line represents a hazard ratio of 1. Each solid circle represents the actual hazard ratios for that predictor, and each horizontal line represents the 95% confidence interval for that predictor.