Differentiation of acute and chronic hepatitis B in IgM antiHBc positive patients

AIM: To identify the factors that differentiate acute hepatitis B(AHB) from chronic hepatitis B with acute exacerbation(CHB-AE).METHODS: From 2004 to 2013, a total of 82 patients(male n = 52, 63.4%; female n = 30, 36.6%) with clinical features of acute hepatitis with immunoglobulin M antibodies to the hepatitis B core antigen(Ig M antiHBc) were retrospectively enrolled and divided into two groups; AHB(n = 53) and CHB-AE(n = 29). The AHB group was defined as patients without a history of hepatitis B virus(HBV) infection before the episode and with loss of hepatitis B surface antigen within 6 mo after onset of acute hepatitis. Biochemical and virological profiles and the sample/cutoff(S/CO) ratio of Ig M anti-HBc were compared to determine the differential diagnostic factors.RESULTS: The multivariate analysis demonstrated that, the S/CO ratio of Ig M anti-HBc and HBV DNA levels were meaningful factors. The S/CO ratio of Ig M anti-HBc was significantly higher in the AHB group, while the HBV DNA level was significantly higher in the CHB-AE group. The optimal cutoff values of Ig M anti-HBc and HBV DNA levels for differentiating the two conditions were 8 S/CO ratio and 5.5 log10 IU/m L, respectively. The sensitivity and specificity were 96.2% and 89.7% for the S/CO ratio of Ig M anti-HBc and 81.1% and 72.4% for HBV DNA levels, respectively. The area under receiver operating characteristic curves of both the S/CO ratio of Ig M anti-HBc and HBV DNA levels were not significantly different(0.933 vs 0.844, P = 0.105). When combining Ig M anti-HBc and HBV DNA, the diagnostic power significantly improved compared to HBV DNA alone(P = 0.0056). The combination of these factors yielded a sensitivity and specificity of 98.1% and 86.2%, respectively.CONCLUSION: The combination of the S/CO ratio of Ig M anti-HBc and HBV DNA levels was a useful tool for differentiating AHB from CHB-AE in patients with positive Ig M anti-HBc.