Are non-invasive fibrosis markers for chronic hepatitis B reliable in sub-Saharan Africa?

Background: In the absence of liver biopsy, the World Health Organization recommends non-invasive tests, such as aspartate aminotransferase to platelet ratio index and FIB-4, to assess liver fibrosis in patients with chronic hepatitis B. However, these tests are not well validated in sub-Saharan Africa. Recently, a new marker, gamma-glutamyl transpeptidase to platelet ratio, was found to be more accurate in an African setting, but this needs confirmation in other cohorts.

Methods: A treatment program for chronic hepatitis B was initiated in Addis Ababa, Ethiopia, in 2015. Non-invasive tests were compared with transient elastography (Fibroscan 402, Echosense, France) using the following thresholds: no fibrosis (≤7.9 kPa), significant fibrosis (>7.9 kPa) and cirrhosis (>11.7 kPa). The diagnostic accuracy was estimated by calculating the area under the receiver operating characteristics curve.

Results: Of 582 treatment-naïve patients, 141 (24.2%) had significant fibrosis and 90 (15.5%) had cirrhosis. The area under the receiver operating characteristics curve of aspartate aminotransferase to platelet ratio index, FIB-4 and gamma-glutamyl transpeptidase to platelet ratio was high both to diagnose significant fibrosis (0.79 [95% CI 0.75-0.84], 0.79 [95% CI 0.75-0.84], 0.80 [95% CI 0.75-0.85]) and cirrhosis (0.86 [95% CI 0.81-0.91], 0.86 [95% CI 0.81-0.91], 0.87 [95% CI 0.82-0.91]). The specificity was high for all tests (94%-100%); however, the sensitivity was poor both to detect fibrosis (10%-45%) and cirrhosis (10%-36%).

Conclusions: Aspartate aminotransferase to platelet ratio index, FIB-4 and gamma-glutamyl transpeptidase to platelet ratio had good diagnostic properties to detect liver fibrosis and cirrhosis in patients with chronic hepatitis B in East Africa. However, the sensitivity was low, and only 10% of patients with cirrhosis were detected using aspartate aminotransferase to platelet ratio index at the World Health Organization recommended threshold.