Large screening with transient elastography shows that hemodialysis patients have higher chances of having fatty liver disease and fibrosis. Amongst hemodialysis populations, non-alcoholic fatty liver disease may be an important determinant of fibrosis.
Liver disease comes in many different forms, most common is steatosis (the accumulation of fat in the liver). While this is not associated with alcoholism, it is termed non-alcoholic fatty liver disease (NAFLD), which affects 15-40% of the global population. Of the people with NAFLD, 20-30% also have nonalcoholic steatohepatitis (NASH), a dysregulation of the inflammatory response which recruits fibroblasts and leaves behind fibrosis. Of those, 10-20% eventually progresses to cirrhosis (chronic damage leading to scarring and failure of the liver) and hepatocellular carcinoma (liver cancer caused by hepatitis infection, high alcohol consumption, or NASH). NAFLD is regarded as the liver manifestation of metabolic syndrome.
The main risk factors which lead to NAFLD, also components of metabolic syndrome, are commonly seen in dialysis patients. One can expect end-stage renal disease (ESRD) patients maintained on hemodialysis to also have a high prevalence of NAFLD.
To detect advanced fibrosis and cirrhosis, the FibroScan device has gained favor amongst professionals in the field. It can non-invasively test for liver fibrosis using transient elastrography (TE), which uses sound waves that bounce and reflect off surfaces in the body, similarly to seismology, which is used to detect advanced fibrosis and cirrhosis. The device also measures the degree of ultrasound attenuation caused by hepatic fat, known as the controlled attenuation parameter (CAP), which can be used to accurately estimate the amount of liver fat present. Because the prevalence of NAFLD in patients undergoing dialysis remains unknown, the aim of this novel study, published in Science Reports, was to find the incidence of liver fibrosis on ESRD patients that are maintained on hemodialysis.
The study population consisted of 659 patients with chronic hemodialysis, of which 51.8% were women, with a mean age of 61.9 ± 11.8 years old, and an average BMI of 22.3±3.4 kg/m2. Additionally, the average liver stiffness measurement (LSM) was 5.9 kPa, 50.5% of the study had hepatic steatosis, and 24.1% had positive viral serology (either HBsAg positive, anti-HCV positive, or both). Patients that had excess alcohol intake and/or had LSM failures were excluded.
Steatosis was found in 50.5% of patients, 24.1% had hepatitis B or C, and 22.6% had LSM ≥ 8.0 kPa. Authors concluded that male hemodialysis patients that are obese, have higher aspartate aminotransferase (AST) levels, lower albumin, lower creatinine, and lower platelet levels are at higher risk and may be good targets for TE assessment. The results suggest that NAFLD may be an important indicator of clinically relevant fibrosis in populations of patients on hemodialysis.
The study has the limitation of a lack of liver biopsies, which are the gold standard used to evaluate liver fibrosis. The authors addressed this by using the Fibrosis 4 calculator (FIB-4) as a comparator for clinically relevant fibrosis. A FIB-4 ≥ 2.67 is recommended by the European Association for the Study of the Liver (EASL) and was used as a surrogate gold standard for clinically relevant fibrosis.
Written By: Kenneth Dominguez, PhD