Unreported AIDS-defining opportunistic illnesses in persons reported with HIV-related severe immunosuppression

To better estimate the distribution of AIDS cases after the 1993 change in the case definition, we assessed the proportion of persons whose AIDS diagnosis was based on laboratory criteria for severe immunosuppression (CD4 count <200 cells/microl or <14%) and who also had an unreported opportunistic illness (OI) at the time of the CD4 report. Five U.S. reporting sites (Arizona; Los Angeles County, California; New Jersey; Oregon; and Washington State) reviewed AIDS cases reported between January 1 and June 30, 1993. From these sites, 3289 immunologic cases were reported; of these cases, 322 (9.8%; range, 1.6%-16.1%) were in persons who had an unreported OI. More of those who had an unreported OI were male, members of racial groups other than white, injection drug users, and had a CD4 count of <50 cells/microl at AIDS diagnosis. Because of recent advances in OI prophylaxis and treatment of HIV infection, studies monitoring HIV-related morbidity should assess the occurrence of OIs in a sample of persons reported with HIV and severe immunosuppression. Such assessment will ensure representative ascertainment of initial AIDS-defining OIs and thus improve the usefulness of the data for public health planning and the allocation of resources for patient care.