Cognitive impairment in people with HIV has multiple causes and HIV-associated neurocognitive disorder is being over-diagnosed, clinicians from Brighton report in Brain Sciences. Assessment of patients attending a specialist HIV memory clinic showed that only 31% met the criteria for HIV-associated neurocognitive disorder (HAND) with an almost equal proportion (27%) having impairment due to mental health problems, sleep disorders or drug use.
Patients attending the Orange Clinic – a collaboration between HIV specialists and memory services in Brighton – were assessed and cared for by a multidisciplinary team. Interventions offered to patients included changing antiretroviral therapy, specialist case-management and follow-up, as well as signposting and referral to other services.
“HIV clinics have always been active in adapting and innovating care models to provide for the changing needs of their patients,” comment the authors. “The Orange Clinic represents such a model – a novel, needs-driven, efficient and coordinated service for the ageing population of PLWH [people living with HIV] who experience neurocognitive issues.”
Cases of HIV associated dementia are now very rare, but some studies have suggested that over a quarter of HIV-positive people aged 50 years and older have the less severe HAND. Assessment for HAND is made using the Frascati criteria (an assessment based on neuropsychological testing). Some researchers have pointed out that these criteria lack precision and do not take into the account the complexity of pathogenic mechanisms that contribute to cognitive impairment, potentially resulting in HAND being over-diagnosed.
Regardless of the precise diagnosis, HIV-positive people with cognitive and memory problems require specialist support. HIV clinicians in Brighton therefore collaborated with local memory services and the Brighton and Sussex Medical School to establish a specialist clinic to assess, manage and support HIV-positive people with suspected cognitive impairment.
The Orange Clinic is multidisciplinary, its staff including an HIV consultant, a consultant old-age psychiatrist skilled in dementia assessment and management, a neuropsychologist, a clinical psychologist and an HIV nurse consultant. Support is provided by neurology and neuroimaging.
Patients undergo a range of neuropsychological tests, including assessment of IQ, memory, attention, language processing, visuo-spatial processing and executive function. Medical histories are thoroughly reviewed. Care also involves a thorough assessment of mental health.
Diagnoses are based on clinical interpretation of an individual's test results, along with factors that can affect cognitive performance, such as mood, mental health and sleep.
Between June 2016 and May 2018 the clinic cared for 52 patients. Their median age was 55 years, 79% were male, 83% were white and the median time since HIV diagnosis was 17 years. The average current viral load was 690 cells/mm3. Only one patient was not currently taking antiretroviral therapy and four individuals had a detectable viral load. A third of the patients reported recreational drug use. On average, patients were taking a mean of five non-HIV medications and 46% were being treated with antidepressants.
Of the 52 people seen, 42 (81%) had HAND using Frascati criteria. However, when the clinicians used their own more sophisticated diagnostic criteria:
- 16 individuals (31%) were diagnosed with HAND.
- 2 people (4%) were diagnosed with dementia, one due to Alzheimer's disease and one of unspecified cause.
- 14 people (27%) had cognitive impairment due to a secondary mental health issue, such as depression, anxiety, drug/alcohol use or poor sleep.
- 7 people (14%) had cognitive impairment due to a non-HIV-related cause, such as cerebrovascular disease or brain injury.
- 11 people (21%) had no objective cognitive impairment.
“It is significant that 27% of those who attended the clinic had a mental health condition which was likely to be responsible for their objective cognitive impairment,” note the authors. “In our clinic it has been vital to be able to address the mental health issues of patients.”
MRI brain imaging showed that two-thirds of patients had some sort of abnormality.
The general intelligence of the patients was comparable to that expected in the wider population. Anxiety, depression and stress scores were all higher than established averages in the general population.
The mean scores for immediate memory, visuo-spacial assessment, language, attention and delayed memory were were all lower than established norms.
The authors suggest that the pattern of cognitive impairment has changed with the availability of combination therapy. In the years before effective treatment, HIV-associated dementia was "characterized by progressive subcortical dementia with prominent degeneration of cognitive and motor functions". Their patients diagnosed with HAND have subtler impairments in tests of immediate and delayed memory, with mild impairments in attention, visuospatial skills and language.
As regards management, 23 patients have been discharged from the clinic. Of those discharged, nine had no objective cognitive impairment and eight had impairment due to mental health problems that could be managed using another service. Three of the discharged patients had mild HAND.
A total of 29 patients are still receiving care at the clinic. Of these, 15 have undergone repeat cognitive assessment and a further eight have been followed up after implementation of a management plan (e.g. psychological therapy, in-clinic advice on mental health/lifestyle/sleep, changes in HIV medication, stricter control of cardiovascular disease risk factors). Other patients are awaiting repeat assessment after further diagnostic tests or remain on the clinic’s books and will be followed-up as warranted.
“Recent modelling work predicts that by 2030 73% of PLWH will be aged over 50 years of age. Multidisciplinary working is vital to the successful management of such patients where complex multimorbidity is likely to be the norm,” conclude the authors. “This service evaluation provides tentative evidence that the need exists, that the model of care we have developed is feasible and that there may be value in establishing similar models of working in HIV care for those with impairment in cognitive function.”