Researchers with the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) report that 53 percent of their cohort of HIV-positive patients has at least mild impairment in thinking, memory and physical coordination—known as cognitive impairment. These data were presented at the Fifth International AIDS Society (IAS) Conference on HIV Pathogenesis, Treatment and Prevention in Cape Town.

Previously reported research indicates that HIV, by itself, can lead to cognitive impairment. People with HIV often have other cofactors—also known as comorbidities—that can lead to cognitive impairment; examples include age, diabetes and hepatitis coinfection. Because of this, researchers are turning their attention to quantifying how these various comorbidities might together increase the risk of cognitive decline.

In a follow-up to data originally presented at the 16th Conference on Retroviruses and Opportunistic Infections (CROI) in Montreal, Igor Grant, MD, from the University of California at San Diego reported on 1,555 HIV-positive patients enrolled at six university sites across the United States. The average age of the study participants was 43, 77 percent were male, 61 percent were non-white, and 28 percent had a history of injection drug use. Researchers compared the level of cognitive impairment with comorbidities.

Overall, 53 percent were found to have at least some cognitive impairment. Grant's group found that those with comorbidities were more likely to have greater cognitive impairment. Of those with minimal impairment, 39 percent had comorbidities; 54 percent with moderate impairment had comorbidities; and 73 percent with severe impairment had comorbidities. Grant's team also found that a greater number of comorbidities was linked with an increasingly severe degree of cognitive impairment.

The authors conclude that HIV and additional comorbidities do combine to increase the risk and severity of cognitive impairment.