Study finds no evidence that HIV-positive gay men in UK have increased risk of neurocognitive impairment

Prevalence and severity of neurocognitive impairment does not differ between HIV-positive and HIV-negative gay men, UK investigators report in the online edition of the Journal of Acquired Immune Deficiency Syndromes. The authors believe their findings have implications for the ways in which cognitive disorders are diagnosed in people living with HIV in the modern treatment era. “Only through correct classification can we maximise the efficacy of recommended interventions in those with true HIV-related cognitive impairment,” comment the authors.

Thanks to effective antiretroviral treatment, HIV-associated dementia is now rare. However, some research has suggested that as many as 50% of people living with HIV have some form of neurocognitive impairment.

Research conducted in the UK, however, has found relatively low rates of cognitive impairment; the 19% prevalence is similar to that seen in the general population.

To further clarify this question, investigators from two London hospitals compared the prevalence of neurocognitive impairment between HIV-positive and HIV-negative gay men. Participants were recruited to the cross-sectional study in 2011-12 and cognitive function was assessed using computer-assisted and pencil and paper tests. Accepted definitions of HIV-associated neurocognitive disorders (HAND – asymptomatic, mild, dementia) and global deficit scores (GDS) were used.

The study population comprised 248 HIV-positive and 45 HIV-negative men. The HIV-positive participants were older than the HIV-negative group (mean age = 46 vs 33 years, p < 0.001). Both groups were predominately white (80%) and 60% had a university education.

Drug and problematic alcohol use – known risk factors for neurocognitive impairment – were highly prevalent in both groups. Rates of depression were higher among people living with HIV compared to the HIV-negative controls (29 vs 8%), but prevalence of moderate-to-severe anxiety did not differ significantly between the two groups (21 vs 14%).

Overall prevalence of HAND was 21% among the people living with HIV. This included 13.7% with asymptomatic impairment, 6.5% with mild impairment and 0.8% with HIV-associated dementia.

Applying the same assessment criteria to the HIV-negative sample showed a neurocognitive disorder prevalence of 29%. Most cases (24%) were asymptomatic and the other cases involved only mild impairment.

These findings were little altered in sensitivity analyses that excluded people with severe depressive symptoms or AIDS-defining neurocognitive disorders.

Prevalence of neurocognitive impairment between the two groups was also comparable when the authors assessed GDS using five domains (HIV-positive = 32% vs HIV-negative = 27%) and ten domains (HIV-positive = 40% vs HIV-negative = 42%).

Factors associated with HAND in the HIV-positive group included lower educational attainment (OR = 3.41 vs. university degree or higher degree, 95% CI, 1.73-6.70, p < 0.001) and increasing age (OR = 1.05 per additional year; 95% CI, 1.01-1.08, p = 0.017).

“Levels of NCI [neurocognitive impairment] in HIV+ MSM [men who have sex with men] in the UK could have been overestimated,” write the authors. “Diagnosed deficits may often not be related to HIV.”

The investigators propose that diagnostic criteria for HAND should be re-evaluated thus:

• Increase level of deficit needed to meet criteria.
• Improve validity of assessments of everyday function.
• Include biomarkers.
• Incorporate repeat assessments.

They also stress the importance of addressing factors associated with the protection of cognitive function in the general population: exercise, stopping smoking, diet, treatment of diabetes and depression.