Baseline results from a longitudinal study of 235 MSM (men who have sex with men) living with HIV, aged 18 to 50, attending an HIV clinic at the Chelsea & Westminster Hospital in London, have found that 29% had clinically defined mood disorders (depression or anxiety) and that, of those who did not, 14% had evidence of significant neurocognitive impairment as defined by a brief neurocognitive screen (BNCS).
The study found, once subjects with mood disorders were screened out, that there was no correlation between self-reported neurocognitive symptoms – such as memory loss – and actual symptoms as detected by the BNCS. There was somewhat better correlation, however, with symptoms reported by friends.
Only a minority of those found symptomatic by the screen have so far been referred for full neuropsychiatric testing and only half of those attended for it.
The study is ongoing, with BNCS testing again six to twelve months after the initial screen, and results compared to a control group of 30 gay, HIV-negative, GUM clinic attendees.
Study subjects were assessed for medical history, current and lowest-ever CD4 count, current and highest-ever viral load, antiretroviral therapy (ART) and drug, tobacco and alcohol use.
Mood disorders are strongly correlated with neurocognitive impairment, both because they can mimic brain impairment (so including people with mood disorders would tend to exaggerate the prevalence of brain impairment), and because people can develop depression or anxiety in response to neurocognitive symptoms (which might lead to underestimating it). People complaining of poor memory were also eliminated from the study as this is not well correlated with HIV-associated neurocognitive disorder.
Once 59 men (28.8% of the total) were excluded for these reasons, the remaining 144 were given three computer-based tests that assessed rapidity of cognitive function and decision-making (executive) ability. Although 97 (67%) had at least one abnormal score on one of the tests, this does not define impairment: it was defined as either having at least two out of three scores within the lowest one-sixth of average group scores or having one score within the lowest 5% of average group scores.
One limitation of this study is that it compared scores within the group rather than with the general population, but the researchers said that results so far did not appear to differ significantly from general-population scores with comparable groups.
To assess the specificity of the BNCS screen, subjects were also given the International HIV Dementia Screen (IHDS), another, more specific. questionnaire-based test. Agreement between the two was relatively good, with only 15% assessed as abnormal by the BNCS having normal results on the IHDS.
Older men were more likely to have abnormal BNCS scores: the average age of those with normal and abnormal scores was 41 and 44 respectively, and 50% of those with an abnormal BNCS result were over 44.
Self-reporting of symptoms did not correlate with abnormal BNCS results. Thirty-five per cent of those with abnormal results reported symptoms of possible neurocognitive impairment, but so did 32% of those with normal results. In contrast, 30% of those whose friends had reported observing symptoms had abnormal results, but only 13% of those who had normal results – so reports of symptoms by others may have more reliability.
In contrast to some previous studies, having normal neurocognitive scores was not associated with current or lowest-ever CD4 count, antiretroviral therapy (ART) or any specific type or ART, or with current or ex-recreational drug use. People with abnormal results were less likely to have a university education (40 vs 62%) and much less likely to be in skilled work (45 vs 81.5%), although this could be a cause or a result of poor neurocognitive function.
Twenty men were not receiving ART: of these, two had low BNCS scores, which was not statistically different from the proportion who were on ART. However, once these were removed from the analysis, men on ART with low BNCS results were less likely to be in a marriage or civil partnership, and more likely to have symptoms reported by others (30%) than self-reported (12%): in other words those off ART significantly over-reported symptoms, possibly reflecting HIV anxiety.
Of the two with low BNCS scores, six were offered a complete neuropsychiatric screen but only three attended. Anxiety about the results might have been the possible cause, the researchers speculated, but in the event only one of the three screened turned out to have significant neurocognitive impairment, and he had other illnesses as well as HIV.
About 40 of the 144 men screened have attended follow-up appointments so far, and the study is ongoing.
This study was not randomised: patients were simply told about it by their doctors, so people with symptoms might be more likely to be referred or enrol. In addition, although people with mood and memory disorders were excluded because they confound neurocognitive screen results, many of them may have had neurocognitive disorders too, so this study cannot establish general prevalence. Furthermore, neurocognitive performance was measured relative to other members of the group being investigated, so the prevalence found will have to be validated by comparison with the HIV-negative control group and reference levels in the general population.
One thing it does establish is that the majority of those who think they have neurocognitive problems don’t, and that friends are a better judge of whether they do have problems than the person themselves. It also finds that, while there is good correlation between this brief BNCS test, which could be used by clinicians within a normal consultation, no one so far has been found to have clinically verified neurocognitive impairment as defined by a full diagnostic assessment.
Barber T et al. Baseline data from the MSM Neurocog Study. Eleventh AIDS Impact Conference, Barcelona, abstract #173, 2013.
