Surveillance for AIDS-defining opportunistic illnesses, 1992-1997.

PROBLEM/CONDITION Acquired immunodeficiency syndrome (AIDS)-defining opportunistic illnesses (OIs) are the major cause of morbidity and mortality among persons infected with human immunodeficiency virus (HIV). As a result of new treatments that reduce mortality for persons with AIDS, the number of persons living with AIDS is increasing, and the incidence of AIDS is decreasing. In 1997, an estimated 271,245 persons were living with AIDS in the United States and thus were at high risk for OIs. In 1997, an estimated 21,909 HIV-infected persons died with AIDS, nearly all as a result of OIs. REPORTING PERIOD COVERED Aggregate data and trends for 1992-1997 were examined to determine a) the frequencies at which OIs occurred first; b) the incidence of OIs; c) the percentage of persons among those who have died who had had a given OI during their course of AIDS, and d) the frequency of prescriptions for antiretroviral therapy and prophylaxis for Pneumocystis carinii pneumonia (PCP) and for Mycobacterium avium complex disease (MAC). DESCRIPTION OF SYSTEM Data were analyzed from the Adult/Adolescent Spectrum of HIV Disease (ASD) sentinel surveillance project, a prospective medical record review of HIV-infected persons aged > or = 13 years conducted in 11 U.S. cities. ASD data were standardized to national AIDS surveillance data for 1992-1997 by age; race; sex; country of birth; year of AIDS diagnosis; HIV exposure mode; and for incidence calculations, by CD4+ T-lymphocyte distribution. RESULTS The incidence declined significantly for each of 15 of the 26 specific AIDS-defining OIs (p<0.05). PCP was the most common AIDS-defining OI to occur first (PCP was the first OI to occur for 36% of HIV-infected persons), the most common incident AIDS-defining OI (274 cases per 1000 person-years), and the most common AIDS-defining OI to have occurred during the course of AIDS (53% of persons who died with AIDS had PCP diagnosed at some time during their course of AIDS). Of persons with CD4+ T-lymphocyte counts <500 cells/microL, the number with prescriptions for triple combination therapy increased from zero in 1992 to 40% in 1997, and 80% of persons had a prescription for any antiretroviral therapy in 1997. Of persons with CD4+ T-lymphocyte counts <200 cells/microL, the percentage with prescriptions for PCP prophylaxis remained stable from 1992 through 1997 (range: 75% to 80%). Of persons with CD4+ T-lymphocyte counts <50 cells/microL, the percentage with prescriptions for MAC prophylaxis increased from 9% in 1992 to 44% in 1997. INTERPRETATIONS The incidences of many OIs are decreasing primarily because of advances in HIV-related therapy. However, OIs are still occurring, especially when patients access care late during the course of disease. Even after accessing care, persons may develop OIs because of lack of prescription for prophylaxis, antiretroviral drug resistance, or poor adherence to therapy. During 1992-1997, most patients in need of PCP prophylaxis received a prescription for it; however, even in 1997, most patients in need of MAC prophylaxis did not receive a prescription for it. ACTIONS TAKEN These surveillance data are used by persons involved with developing guidelines for preventing OIs to determine the importance of and trends in OIs and preventive therapy. CDC is developing population-based approaches for surveillance of HIV disease progression, OIs, and therapies with the goal of making these data available in more geographic areas to help assess public health and health-care programs.