A new non-invasive test can be used to diagnose the degree of liver damage in patients co-infected with HIV and hepatitis, according to the results of a French study presented in the 1st February edition of The Journal of Acquired Immune Deficiency Syndromes. This new technique may reduce the need for painful liver biopsies in co-infected patients.
Infection with the hepatitis C virus usually leads to progressive liver damage, called fibrosis, culminating in irreversible scarring of the liver. This scarring, or cirrhosis, causes complications such as liver failure, fluid retention, bleeding in the gut and liver cancer.
The current ‘gold standard’ for the assessment of fibrosis and cirrhosis is to take a small sample or ‘biopsy’ of the liver for examination under the microscope. This painful, invasive procedure can cause life-threatening complications and its reliability is limited by the small size of the sample and variability between observers.
The new technique, which measures the stiffness of the liver with a probe that is held against the skin, has been shown to be effective in HIV-negative patients. A scan takes around five minutes, has no side-effects and is painless. The new findings confirm its effectiveness in patients co-infected with HIV.
“Liver stiffness measurement could reliably be used for first-line pre-therapeutic evaluation of fibrosis in co-infected patients,” the researchers write. “Moreover, for the diagnosis of cirrhosis, liver stiffness is more accurate that other non-invasive biochemical tests.”
The investigators carried out liver biopsies and transient elastography measurements in of 72 patients. They found that the results of the non-invasive technique correlated significantly with the degree of liver fibrosis detected in the liver biopsies (p < 0.001). This indicates that the probe, called FibroScan, can be used to detect the degree of fibrosis.
“Liver stiffness measurement is a promising non-invasive method for the assessment of fibrosis in HIV-infected patients with chronic hepatitis C virus infection,” they conclude.
FibroScan was also very effective at diagnosing cirrhosis of the liver in the patients, with 97% accuracy. The investigators calculated that a stiffness measurement of 11.8 kPa or greater indicates that the patient has cirrhosis of the liver. This is similar to the value found in two studies of HIV-negative patients.
The investigators also compared the results of transient elastography to blood measures that can be used to detect cirrhosis. They found that the new technique was more accurate than all four measurements: platelet count (p = 0.02), the ratio of the liver enzymes aspartate aminotransferase (AST) to alanine aminotransferase (ALT; p < 0.001), the AST-to-platelet ratio index (APRI; p = 0.01) and FIB-4 (p = 0.004).
FibroScan is not yet available for diagnosis of liver damage in United Kingdom hospitals. If future studies confirm these findings, however, its introduction may improve the management of hepatitis C patients with and without HIV co-infection.
de Lédinghen V et al. Diagnosis of hepatic fibrosis and cirrhosis by transient elastography in HIV/hepatitis C virus-coinfected patients. J Acquir Immune Defic Syndr 41: 175-179, 2006.