Role of serum M2BPGi levels on diagnosing significant liver fibrosis and cirrhosis in treated patients with chronic hepatitis B virus infection

BACKGROUND: Mac-2-binding protein glycosylation isomer (M2BPGi), a novel serum marker for liver fibrosis, was seldom studied in chronic hepatitis B (CHB). We aimed to evaluate its role on diagnosing significant fibrosis and cirrhosis in treated CHB patients. METHODS: CHB patients treated with nucleos(t)ide analogues (NAs) with baseline liver biopsies and retrievable serum samples were recruited. Paired liver biopsies were performed in patient subgroups at 1 and 3 years. RESULTS: In total, 327 NA-treated CHB patients (M:F = 229:98; median age 38.1 years) were recruited. The median M2BPGi values were 0.26, 0.34, 0.57 and 1.21 cutoff index (COI), in liver histology with Ishak F0–1, F2, F3 and F4, respectively (p < 0.01). M2BPGi levels correlated with the Ishak scores (ρ = 0.312, p < 0.001). Using the cutoff values of 0.25, 0.45 and 0.96 COI for ≥F2, ≥F3 and F4, the AUROCs were 0.653, 0.795 and 0.914, respectively. Multivariate analysis with several other serum indices showed that M2BPGi was the most significant independent factor for ≥F3 (OR: 8.197, 95% CI: 2.699–24.897, p < 0.001). In patient subgroups with serial liver biopsies, both the proportion of F3/F4 and M2BPGi decreased at 1 year (8.3% vs. 2.8% and 0.32 vs. 0.21 COI, respectively; both p < 0.001). Histological fibrosis progression after ≥3 years of NA therapy accompanied with an increase in M2BPGi level, compared to patients without progression (+0.14 vs −0.03 COI, p = 0.045). CONCLUSION: Serum M2BPGi is a reliable non-invasive marker for diagnosing ≥F2, ≥F3 and F4. It is the only significant marker for ≥F3 among several other indices. NA produced concordant dynamic changes in M2BPGi levels and histological fibrosis.