Bacterial pneumonia in persons infected with the human immunodeficiency virus

Patients with human immunodeficiency virus (HIV) infection are at increased risk for bacterial pneumonia in addition to opportunistic infection. However, the risk factors for bacterial pneumonia and its incidence in this population are not well defined. In a multicenter, prospective, observational study, we monitored 1130 HIV-positive and 167 HIV-negative participating adults for up to 64 months for pulmonary disease. The HIV-positive group comprised 814 homosexual or bisexual men, 261 injection-drug users, and 55 female partners of HIV-infected men. There were 237 episodes of bacterial pneumonia among the HIV-positive participants (rate, 5.5 per 100 person-years), as compared with 6 episodes among the HIV-negative participants (rate, 0.9 per 100 person-years; P<0.001). The rate of bacterial pneumonia increased with decreasing CD4 lymphocyte counts (2.3, 6.8, and 10.8 episodes per 100 person-years in the strata with more than 500, 200 to 500, and fewer than 200 cells per cubic millimeter, respectively; P<0.022 for each comparison). Injection-drug users had a higher rate of bacterial pneumonia than did homosexual or bisexual men or female partners. In the stratum with the fewest CD4 lymphocytes, cigarette smoking was associated with an increased rate of pneumonia. Mortality was almost four times higher among participants with an episode of pneumonia than among the others. Prophylaxis with trimethoprim–sulfamethoxazole was associated with a 67 percent reduction in confirmed episodes of bacterial pneumonia (P = 0.007). Bacterial pneumonia is more frequent in HIV-positive persons than in seronegative controls, and the risk is highest among those with CD4 lymphocyte counts below 200 per cubic millimeter and among injection-drug users. Pulmonary infections are a major cause of morbidity and mortality in persons with human immunodeficiency virus (HIV) infection.¹–³ Although Pneumocystis carinii pneumonia has received more attention, bacterial pneumonia also occurs frequently among such persons.⁴–⁶ Prompt and accurate diagnosis is essential, because the outcome of HIV-associated bacterial pneumonia appears reasonably good with appropriate treatment.⁵,⁷ However, the epidemiologic characteristics of bacterial pneumonia have not been well defined.⁷ Moreover, the risk factors for bacterial pneumonia, which may be useful in developing strategies of diagnosis and management, remain largely uninvestigated.⁸ The Pulmonary Complications of HIV Infection Study is a multicenter, longitudinal.