Does Older Age Confer an Increased Risk of Incident Neurocognitive Disorders Among Persons Living with HIV Disease?

Objective: This study aimed to determine the combined effects of age and HIV infection on the risk of incident neurocognitive disorders. Method: A total of 146 neurocognitively normal participants were enrolled at baseline into one of four groups based on age (<= 40years and >= 50years) and HIV serostatus resulting in 24 younger HIV-, 27 younger HIV+, 39 older HIV-, and 56 older HIV+ individuals. All participants were administered a standardized clinical neuropsychological battery at baseline and 14.3 +/-.2months later. Results: A logistic regression predicting incident neurocognitive disorders from HIV, age group, and their interaction was significant (chi(2)[4]=13.56, p=.009), with a significant main effect of HIV serostatus (chi(2)[1]=5.01, p=.025), but no main effect of age or age by HIV interaction (ps>.10). Specifically, 15.7% of the HIV+ individuals had an incident neurocognitive disorder as compared to 3.2% of the HIV- group (odds ratio=4.8 [1.2, 32.6]). Among older HIV+ adults, lower baseline cognitive reserve, prospective memory, and verbal fluency each predicted incident neurocognitive disorders at follow-up. Conclusions: Independent of age, HIV infection confers a nearly fivefold risk for developing a neurocognitive disorder over approximately one year. Individuals with lower cognitive reserve and mild weaknesses in higher-order neurocognitive functions may be targeted for closer clinical monitoring and preventative measures.