This question is raised by a new study published in JAMA Network Open.2 According to data from over 177,000 US veterans diagnosed with dementia, a number of them may have reversible neurological problems involving unrecognised liver disease.
In 5 to 10 per cent of these dementia patients who had not previously been diagnosed with cirrhosis, the researchers found a high Fib-4 level, which indicates advanced liver fibrosis to cirrhosis and could indicate hepatic encephalopathy (HE) as a risk factor for cognitive impairment.
The Fibrosis-4 (FIB-4) Index is a screening or estimation parameter for the degree of liver damage, e.g. in the context of viral hepatitis, alcoholic or fatty liver disease. For the score, only the age, the transaminases ASAT and ALAT and the platelet count are required and these can be entered into one of the many available online laboratory calculators.
An FIB-4 score >2.67 indicates advanced fibrosis and >3.25 indicates cirrhosis, which applied to 10.3 per cent and 5.3 per cent of those examined respectively. Higher Fib-4 scores were associated with older age, heart failure, viral hepatitis, alcohol consumption and renal insufficiency.
The good news? HE, unlike dementia, is highly treatable. Veterans often suffer from comorbidities that can impair cognitive function, such as alcohol abuse, post-traumatic stress disorder (PTSD) and head injury, in addition to risk factors for cirrhosis. However, the results were similar in a regional validation cohort of dementia patients, where up to 11.2 per cent had elevated FIB-4 levels. Further confirmatory studies from the general population would be necessary and are currently being prepared by the study authors.
The FIB-4 score should be used in older people with dementia as a first step or screening tool to diagnose or rule out HE as a possible factor for cognitive impairment, the authors summarise. "Routine use of the FIB-4 index [...] could help a large number of patients, families and physicians by providing an opportunity to treat and potentially reverse cognitive impairment caused by liver disease."3
In dementia patients with established liver cirrhosis, HE and dementia symptoms overlap considerably. Patients with both comorbidities have a demonstrably poorer quality of life, which improves after HE treatment.
The authors emphasise that beyond this association, it is important not to overlook advanced cirrhosis in this population so that patients can also be screened for hepatocellular carcinoma and other cirrhosis complications. They explain that "early detection of liver problems enables targeted interventions and opens up opportunities to address treatable factors that contribute to cognitive decline."3