Prevalence of self-reported neurocognitive impairment falls among people with HIV in Switzerland

Depression, poor adherence and opportunistic infections associated with persisting impairment
Image: Maya Kruchankova/

Persisting neurocognitive impairment in people with HIV is associated with a serious central nervous system infection in the past, depression and less than perfect adherence to antiretroviral therapy (ART), Swiss investigators report in the online edition of Clinical Infectious Diseases. Individuals with these characteristics could benefit from regular assessment to help diagnose problems with memory and understanding, say the authors.

Data on symptoms of neurocognitive impairment were obtained using self-completed questionnaires during routine HIV follow-up visits. Although the prevalence of self-reported neurocognitive impairment fell by almost half during the four years of the study, the investigators were also able to identify a group of individuals with persisting high-level impairment. This cluster of individuals were more likely than those with little evidence of impairment to have a history of AIDS-defining central nervous system (CNS) opportunistic infections, depression and to regularly miss doses of their HIV medication.

“Despite the overall decline in SRNI [self-reported neurocognitive impairment], there are still patients with persisting SRNI,” comment the authors. “It is well-known that effective ART alone cannot eliminate neurocognitive problems…it is therefore crucial to understand the different factors associated with SRNI and to identify the groups of patients without improvement over time.”


central nervous system (CNS)

The brain and spinal cord. CNS side-effects refer to mood changes, anxiety, dizzyness, sleep disturbance, impact on mental health, etc.


A mental health problem causing long-lasting low mood that interferes with everyday life.

transmission cluster

By comparing the genetic sequence of the virus in different individuals, scientists can identify viruses that are closely related. A transmission cluster is a group of people who have similar strains of the virus, which suggests (but does not prove) HIV transmission between those individuals.

longitudinal study

A study in which information is collected on people over several weeks, months or years. People may be followed forward in time (a prospective study), or information may be collected on past events (a retrospective study).

adjusted odds ratio (AOR)

Comparing one group with another, expresses differences in the odds of something happening. An odds ratio above 1 means something is more likely to happen in the group of interest; an odds ratio below 1 means it is less likely to happen. Similar to ‘relative risk’. 

Dr Katharina Kusejko from University Hospital Zurich and colleagues from the Swiss HIV Cohort Study wanted to determine the prevalence of self-reported neurocognitive impairment in the cohort and to see if the condition was associated with any particular characteristics.

They therefore designed a longitudinal study based on answers provided to a questionnaire used to assess self-reported neurocognitive impairment. This questionnaire has been part of routine HIV care in Switzerland since 2013.

The questionnaire includes questions about frequent memory loss, concentration difficulties and reasoning difficulties. Possible answers are “never”, “hardly ever” and “yes definitely.” Individuals answering “yes definitely” to any of the questions were defined as having self-reported neurocognitive impairment.

Analysis of the answers provided during follow-up was also used to place participants into three distinct clusters: little or no evidence of impairment; improving impairment; persistent impairment.

Medical records were used to see if an individual had ever been diagnosed with an AIDS-defining opportunistic infection of the CNS (HIV-related encephalopathy, toxoplasmosis of the brain, progressive multifocal leukoencephalopathy, cryptococcal meningitis, primary lymphoma of the brain and encephalitis).

Individuals were considered to have a history of depression if a psychiatrist or other physician had diagnosed the condition. Adherence to ART was considered sub-optimal if individuals reported missing one or more doses on a weekly basis.

"The proportion of individuals with self-reported neurocognitive impairment fell from 20% in 2013 to 11% in 2017."

The study population consisted of 8545 individuals who had completed five or more neurocognitive impairment questionnaires between 2013 and 2017.

The proportion of individuals with self-reported neurocognitive impairment fell from 20% in 2013 to 11% in 2017. The investigators suggest that prompt initiation of ART with potent regimens could be a reason for this almost 50% fall.

Comparison of the clinical and demographic characteristics of individuals with and without self-reported neurocognitive impairment revealed several differences. Those with self-reported impairment were older, were more likely to be female (31% vs 28%) and to have a history of injecting drug use (18% vs 9%). They were also more likely to have been diagnosed with an opportunistic infection of the CNS (6% vs 3%), have a history of depression (46% vs 23%) and to report imperfect adherence to ART (16% vs 10%).

The majority of participants (80%) had little or no evidence of neurocognitive impairment (cluster one); 13% had improving impairment scores (cluster two); and 7% had persistent impairment (cluster three).

Comparison between clusters one and three identified three key characteristics associated with persistent impairment: a previous opportunistic infection of the CNS (AOR = 3.9, p<0.001), imperfect adherence to ART (AOR = 3.1, p<0.001) and depression (OR = 1.9, p<0.001).

“Our results suggest that all patients with a history of CNS opportunistic infections should be screened in depth for neurocognitive problems,” conclude the authors. “Patients reporting imperfect adherence to ART or having a depression should be considered for further screening of neurocognitive problems. Selecting patients for in-depth neurocognitive screening based on these three criteria is in particular useful for cohorts and patients without longitudinal information about self-reported neurocognitive impairment.”