TORONTO — In older patients with HIV, increased cerebrovascular risk factors, as measured by the Framingham Risk Score for Stroke, may be associated with increased HIV-associated neurocognitive impairment, according to data presented at the American Psychiatric Association Annual Meeting.
“In 2008, the CDC estimated that 30% of all HIV patients are 50 years of age or older, and they projected that by 2018, that number will double,” researcher Alan T. Rodríguez Penney, a fourth-year medical student, told Healio.com/Psychiatry. “So we have more than half of the HIV population reaching 50 years of age or older, and older age is also a risk factor for cerebrovascular and cardiovascular disease. We wanted to see if there was any synergistic effect between age and HIV serostatus, and whether there was any association between Framingham Risk Score for Stroke (FRS-S) and HIV-associated neurocognitive disorder (HAND).”
Rodríguez Penney and colleagues evaluated 64 HIV-positive participants diagnosed with HAND based on Frascati criteria. Of these, 43 participants were aged 50 years or older (90.7% male), and 21 were aged 40 years or younger (81% male). A group of 105 HIV-negative participants was also included: 61 were aged 50 years or older (70.5% male) and 44 were aged 40 years or younger (70.5% male). The researchers used multivariable regression to control for hepatitis C infection, psychiatric comorbidities and other demographic characteristics. After adjusting for these variables, the researchers found a significant interaction between age and HIV on FRS-S (P = .02).
In a planned post-hoc analysis, they found that among the older individuals, those in the HIV-positive cohort had higher FRS-S scores than those in the HIV-negative group (P = .002), while no difference in FRS-S score was observed in the younger groups based on HIV serostatus (P = .43).
“We saw there is an age and HIV serostatus interaction — a synergistic effect causing a higher score in the FRS-S,” Rodríguez Penney said. “When we compared the older population, the HIV-positive group had a much higher FRS-S score than the HIV-negative older population. In the younger population, there isn’t as much of a difference.”
Among the older HIV-positive participants, slightly higher FRS-S scores were seen in those with Minor Neurocognitive Disorder than those with Asymptomatic Neurocognitive Impairment (P =. 06).
Among older individuals with HIV, increased FRS-S scores were strongly correlated with poorer performance on tests of delayed verbal memory (Ps < .05).
The findings suggested that cerebrovascular risk factors affect the expression of HAND across the lifetime of HIV patients.
“We found that there are cerebrovascular risk factors that are more associated with HAND than the actual HIV risk factors, such as CD4 count and plasma viral load,” Rodríguez Penney said.
He noted that based on these and previous findings, the researchers believe there is an inflammatory mechanism involved in these associations.
“Other studies have associated increased carotid intima media thickness with neurocognitive impairment, so we believe that the chronic inflammatory effects of HIV serostatus and antiretroviral medications lead to a higher FRS-S score in the older population,” he said. “We think the older population is more impacted because of the longer duration of time they have had for the chronic inflammation to take effect, relative to the younger population.”
The researchers wrote that additional studies involving neuroimaging, biomarkers and neuropathology are needed to fully elucidate the mechanism of vascular injury in older HIV patients.
“This leads to a new area of emphasis for potential future targets,” Rodríguez Penney said. “We’ve been targeting CD4s and plasma viral load very well, but if we want to avoid neurocognitive impairment in this increasingly large older population, we want a particular focus on cerebrovascular and cardiovascular risk factors.” – by Jennifer Byrne
Rodríguez-Penney AT. #P6-014. Presented at: The American Psychiatric Association Annual Meeting; May 16-20, 2015; Toronto.
Disclosure: Rodríguez Penney reports no relevant financial disclosures.