Epidemiology of Pneumocystis carinii pneumonia

Background: Despite the availability of effective prophylactic therapy, Pneumocystis carinii pneumonia (PCP) remains a common opportunistic Illness among HIV-infected persons. Methods: Since February 1996, we have conducted prospective surveillance for laboratory-confirmed cases of PCP at seven hospitals caring for HIV-infected patients in Seattle and Los Angeles to describe risk factors for infection. Data from interviews with the first 109 subjects are presented. Results: The mean age of subjects was 37 years, 96 (88%) were male. The median CD4 lymphocyte count closest to the time of PCP diagnosis was 27 cells/μl (intraquartile range 10-48). Sixty subjects (55%) were white, 22 (20%) black; 30 (28%) were Hispanic. Among men, 76 (79%) reported a history of male-male sex and 9 (10%) reported intravenous drug use. Among 109 subjects with primary or secondary PCP, 43 (39%) reported not receiving ongoing medical care in the 6 months prior to PCP. Forty-four subjects (40%) reported having no medical insurance at the time of diagnosis. During the 12 weeks prior to PCP diagnosis, 49 (45%) persons received no PCP prophylaxis including 12 of 66 (18%) persons with and 37 of 43 (86%) persons without a usual medical care provider (OR 27.8, 95% CI 8.6-94.6, p <0.001). Among 80 persons with a first episode of PCP. 22 (28%) had not been previously tested for HIV. Conclusions: A large proportion of persons with PCP report no ongoing medical care with a usual provider and a large proportion of persons with primary PCP have not been previously tested for HIV. Strategies to improve access to medical care and awareness of HIV infection among persons at risk may lead to decreased rates of PCP.