HIV-INFECTION AND COGNITION IN INTRAVENOUS-DRUG-USERS - LONG-TERM FOLLOW-UP

A cohort of 185 HIV-infected injection drug users (IDUs) and seronegat ive controls was followed with semiannual neuropsychological assessmen ts for up to 4.5 years. Changes in cognitive performance over time wer e evaluated, and results of seronegative controls were used to adjust for level of education and practice effects. The effects of duration o f follow-up, decline in CD4+ count, development of clinical symptoms, antiretroviral use, and diagnosis of AIDS on changes in neuropsycholog ical performance over time were assessed with regression models using the generalized estimating equation approach. Improvement in performan ce over time, consistent with practice effects, was observed for all m easures. The only subtest for which the magnitude of the practice effe cts was mildly attenuated relative to the seronegative controls was Gr ooved Pegboard, dominant hand. After adjusting for disease progression and antiretroviral therapy use, none of the time trends for the neuro psychological test scores were significant, suggesting no decline in p erformance of the seropositive patients relative to the seronegative c ontrols. With development of clinical symptoms, there was a trend in t he direction of declining performance. For subjects reporting two or m ore symptoms but not using antiretroviral therapy, the trend was not s ignificant, whereas having two or more symptoms and using antiretrovir al therapy was associated with significantly worse performance on test s of psychomotor speed and memory. With development of AIDS, a signifi cant decline in performance was observed on measures of motor and psyc homotor speed as well as memory. There is thus no evidence to suggest that HIV infection in the context of chronic drug and alcohol use sign ificantly alters the frequency or rate of progression of cognitive sym ptoms. These findings suggest that the natural history of cognitive ch anges secondary to HIV infection is similar among HIV-infected IDUs an d other risk groups such as homosexual/bisexual men.