Validation of four AIDS-case definitions in HIV-infected intravenous drug users in Barcelona, Spain

Abstract

The objective of the study is to assess the sensitivity and specificity of four epidemiological AIDS-Case Definitions (CDC-87, CDC-93, Europe-93 and Revised Caracas) in HIV-infected intravenous drug users (IDU). The authors carried out a cross-sectional study with 136 IDUs, HIV-infected from a Men Penitentiary Center and from a drug addiction treatment center of Barcelona, Spain, between October/93 and April/94. A protocol, including demographic, clinical and laboratory variables was used by one doctor and the laboratory tests were done in the same institution. After that, the patients were classified in the four Epidemiological AIDS-Case Definitions used by this study. As gold standard we used the CD4 Cell Count (out point 200 or 14% CD4+). The number of AIDS cases varied between 31 and 84 according to the type of AIDS definition. The CDC-93 AIDS definition implied an increase of 170.9% in the number of cases in relation to CDC-87 AIDS-Case Definition. The sensitivities of the CDC-87, CDC-93, Europe-93 and Revised Caracas Epidemiological AIDS - Case Definitions were 34.2, 88.6, 45.6 and 56.9% while the specificities were 93.0, 75.4, 75.4 and 77.2%, respectively. The positive predictive values were between 72.0% (Europe-93) and 87.1% (CDC-87) and the negative predictive values were between 50.0% (Europe-93) and 82.7% (CDC-93). The authors concluded: the sensitivity and specificity of Caracas Revised Epidemiological AIDS-Case Definition was better than Europe-93 AIDS Case Definition. So this Definition can be very useful in countries and situations where the CD4 Cell Count is not available for technical or economical reasons.