Factors associated with the CD4⁺ lymphocyte count at diagnosis of acquired immunodeficiency syndrome

To assess which factors are associated with the CD4⁺ lymphocyte count at the time of AIDS diagnosis we studied 3046 patients in the AIDS IN EUROPE study who were diagnosed with AIDS in 1 of 17 European countries between 1979 and 1989 and for whom the CD4 count at AIDS diagnosis was known. Data were extracted retrospectively from patient case notes, using a standardized form. There was a wide range of average CD4⁺ lymphocyte counts at AIDS diagnosis, according to which diseases were present at diagnosis. The highest geometric mean CD4⁺ lymphocyte counts at AIDS diagnosis were associated with the diagnosis of extrapulmonary tuberculosis, Kaposi's sarcoma, and non Hodgkin's lymphoma while the lowest counts were found when histoplasmosis and cytomegalovirus (CMV) retinitis were present. There were no appreciable differences between CD4⁺ lymphocyte counts at AIDS in patients according to the three major transmission route categories (sex, age, or region of diagnosis) but there was a marked trend (P <0.005) toward lower CD4⁺ lymphocyte counts at AIDS diagnosis in more recent years. These associations remained largely unchanged after adjustment for other factors.