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Risk score can identify which HIV-positive people with controlled viral load are at greatest risk of neurocognitive decline
Michael Carter, 2017-06-16 07:30:00
Four factors are
associated with neurocognitive decline in people living with HIV with an
undetectable viral load, investigators from Canada report in the online edition
of the Journal of Acquired Immune
Deficiency Syndromes. The strongest individual risk factor was impaired
kidney function, indicated by eGFR < 50ml/min. People with all four
risk factors had a 95% risk of neurocognitive decline over three years,
compared to a 2% risk for people with no risk factors.
risk index included four clinical factors that were significant predictors of
neurocognitive decline,” comment the authors. “Lower eGFR was the strongest
Neurocognitive changes such as memory loss, inability to remember words, loss of verbal fluency, poor concentration and inability to take in new information or make complex decisions are features of ageing, but happen at different speeds for different people. A number of health conditions may have an impact on neurocognitive function.
There is a body of
research suggesting that people with HIV remain at increased risk of
neurocognitive decline, even when they are taking effective antiretroviral
therapy and have an undetectable viral load. The risk factors for decline in
these people are uncertain. Identification of such risk factors could assist
the development of targeted interventions to prevent avoidable declines.
McGill University, Canada, therefore designed a prospective study involving 191 HIV-positive adults, all with a controlled viral load. Their aim was to
determine the baseline socio-demographic, clinical, biological and lifestyle
factors associated with neurocognitive decline.
monitored for three years. At six-monthly intervals, they underwent a battery
of 15 tests to assess neurocognitive function. Individuals who deteriorated by
at least 0.5 SD on at least one assessment were defined as having
On entry to the
study, the participants had a median age of 45 years, 74% were male and 52%
were non-Caucasians. Participants had spent a median of 12 years in education,
and had been living with diagnosed HIV infection for a median of ten years.
Average current CD4 cell count was 514 cells/mm3. Almost all (94%)
were currently taking HIV therapy.
Over three years,
23 people (12%) showed evidence of decline in at least one neurocognitive assessment.
for potential confounders, four baseline factors had a significant association
with neurocognitive decline:
- eGFR < 50 ml/min (OR =
18.14; 95% CI, 1.53-254.53).
Diagnosed HIV infection for 15
or more years (OR = 11.14; 95% CI, 1.61-88.08).
Education for 12 years or
less (OR = 5.45; 95% CI, 1.44-24.09).
Cerebrospinal fluid (CSF)
protein above 45 mg/dl (OR = 4.55; 95% CI, 1.36-15.74).
suggest that impaired eGFR could be indicative of vascular disease in both the
kidney and the brain. “Lower eGFR is a known independent predictor of
atherosclerotic vascular disease,” they note. “In non-HIV individuals, lower
eGFR has been independently associated with lower cerebral blood flow,
cognitive decline and increases the risk of recurrent stroke and small brain
infarctions, both possible risk factors for cognitive decline.”
However, they emphasise that more research is needed to understand the relationship between declining kidney function and neurocognitive changes.
longer duration of HIV infection could, the investigators suggest, have had a
considerable amount of time without effective HIV treatment.
risk of decline over three years was 2% for individuals with none of these four
risk factors. Having only impaired eGFR increased the risk to 21%. Having all
four risk factors was associated with a 95% increase in risk.
patients with their individualized risk of cognitive decline may increase their
motivation for behavioral changes and adherence to treatment,” conclude the
authors. “The case will become more compelling as the findings are replicated
in other samples, and the link between the neurocognitive outcome we studied and real
life function is established.”
Lifestyle factors such as diet, exercise, alcohol intake, smoking and weight may be amenable to change and may result in improved cognitive function, but more research is needed on this topic in people living with HIV.