EPIDEMIOLOGY OF AIDS DEMENTIA COMPLEX IN EUROPE

The aim of the study was to describe the epidemiology of AIDS dementia complex (ADC) in Europe and to assess the possible role of zidovudine therapy in preventing or delaying its occurrence. We used an inceptio n cohort, with data collected retrospectively from patients' clinical records from 52 clinical centers in 17 countries across Europe. The su bjects were 6,548 adult people with AIDS consecutively diagnosed from 1979 to 1989. The main outcome measures were codiagnosis of ADC at the time of AIDS diagnosis and ADC-free time after AIDS diagnosis. ADC wa s reported in 295 patients (4.5%) at the time of AIDS diagnosis and du ring follow-up in a further 402 of the 5,160 patients (7.8%) who were diagnosed with AIDS based on diseases other than ADC. Whether at the t ime of AIDS diagnosis or later, the occurrence of ADC was significantl y associated with age, transmission category, and CD4(+) cell counts. The risk was greater in older patients (14 and 19% greater, at AIDS di agnosis and after, respectively, for a 5-year difference in age), in i .v. drug users than in homosexual and bisexual men (89 and 60% greater , at AIDS diagnosis and after, respectively), and for people with lowe r CD4(+) cell counts (14 and 30% greater for a reduction of 1 on the n atural log scale). Risk was almost double for women than for men. A si gnificant reduction, of similar to 40%, was found in the risk of devel oping ADC after AIDS diagnosis for patients receiving zidovudine thera py, but this effect was present only during the first 18 months of tre atment, irrespective of whether treatment began before or after AIDS d iagnosis. In conclusion, an increase in the risk of developing ADC eit her at the time of AIDS diagnosis or thereafter is associated with inc reasing age, i.v. drug use, and decreased CD4(+) cell count. Women ten d to have a higher risk of ADC at the time of AIDS diagnosis. Zidovudi ne therapy appears to have a definite, but time-limited, effect of pro tecting patients against ADC development after AIDS diagnosis.