Bacterial Pneumonia in Persons Infected with the Human Immunodeficiency Virus

Abstract

Background. Patients with human immuno-deficiency virus (HIV) infection are at increased risk for bacterial pneumonia in addition to opportunistic in-fection. However, the risk factors for bacterial pneumo-nia and its incidence in this population are not well de-fined. Methods. In a multicenter, prospective, observational study, we monitored 1130 HIV-positive and 167 HIV-neg-ative participating adults for up to 64 months for pulmo-nary disease. The HIV-positive group comprised 814 ho-mosexual or bisexual men, 261 injection-drug users, and 55 female partners of HIV-infected men. Results. There were 237 episodes of bacterial pneu-monia 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 Ͻ 0.001). The rate of bacterial pneumonia in-creased 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 р 0.022 for each com-parison). Injection-drug users had a higher rate of bacte-rial pneumonia than did homosexual or bisexual men or female partners. In the stratum with the fewest CD4 lym-phocytes, cigarette smoking was associated with an in-creased rate of pneumonia. Mortality was almost four times higher among participants with an episode of pneu-monia than among the others. Prophylaxis with trimetho-prim–sulfamethoxazole was associated with a 67 percent reduction in confirmed episodes of bacterial pneumonia (P ϭ 0.007). Conclusions. Bacterial pneumonia is more frequent in HIV-positive persons than in seronegative controls, and the risk is highest among those with CD4 lympho-cyte counts below 200 per cubic millimeter and among injection-drug users. (N Engl J Med 1995;333:845-51.)