CHANGING INCIDENCE OF PNEUMOCYSTIS-CARINII PNEUMONIA AS INITIAL AIDS-DEFINING DISEASE IN THE UNITED-KINGDOM

Objective: To determine whether the incidence of Pneumocystis carinii pneumonia (PCP) as the initial AIDS-defining disease in adult AIDS cas es in the United Kingdom is changing over time and to examine factors likely to affect it. Subjects and methods: A total of 4419 adult AIDS cases diagnosed in the United Kingdom between January 1989 and Decembe r 1992 were analysed using logistic regression models. An initial diag nosis of PCP was used as the outcome variable and the possible effects of age, sex, exposure category, ethnic group, half year of diagnosis, geographical area of report, and whether or not the individuals had b een aware of their HIV infection when AIDS was diagnosed was examined. Results: A significant decline in PCP incidence was observed over tim e. Incidence of PCP declined among subjects who had been aware of thei r infection for 9 months or more before AIDS diagnosis. There was no e vidence of a change in PCP incidence over time for subjects who had ha d HIV infection diagnosed 3 or less months before an AIDS diagnosis. I ndividuals who had been aware of their HIV infection, individuals repo rted from the Thames health regions, and non-white patients were much less likely to have had a diagnosis of PCP. Conclusions: The decline o f PCP incidence in subjects aware of their serostatus, and therefore m ore likely to have received primary prophylaxis, suggests that they ma y have benefited from this treatment. Our findings provide evidence of the value of an early HIV diagnosis and confirmation of the beneficia l effects of primary prophylaxis for PCP.