Risk of AIDS dementia after the interruption of treatment with zidovudine

BACKGROUND: Epidemiologic data suggest that zidovudine (ZDV) could prevent the AIDS dementia complex (ADC), but this hypothesis has not been specifically studied. PATIENTS AND METHODS: We have reviewed the medical records of all patients with human immunodeficiency virus (HIV) infection admitted to our section between January 1990 and December 1993 who were diagnosed with ADC, and we have compared them to those of a control group with regard to the interruption of ZDV at least 3 months before. Controls were selected from the remaining HIV-related admissions, matched by calendar year, CD4-cell count and previous HIV-disease stage. RESULTS: Thirty-nine cases and 39 controls were available for analysis; twenty-nine (74%) and 25 (64%) were male. The median age was similar for both groups: 30. Thirty-one patients (79%) in each group had a previous diagnosis of AIDS, six (15%) in each group had an AIDS-related complex and in two (5%) the ADC was the first complication of their HIV disease. The median CD4-cell counts were 79.6 and 79.4 x 10(6)/l.. Twenty-three patients in each group had taken ZDV. Six of these from the ADC group had withdrawn treatment, as compared to 2 from the control group (odds ratio [OR] 3.36; 95% confidence interval [CI]: 0.54-35.76). On the other hand, 16 patients with ADC were still on ZDV at the time of diagnosis, as compared to 21 controls (OR: 0.66; 95% CI: 0.22-1.60). CONCLUSION: In this case-control study, the interruption of treatment with ZDV was not found to be a risk factor for the developement of ADC.