Low accuracy of the national reporting system of acute hepatitis C infection in Taiwan, 1995-2004.

Background and Aim:  This study attempted to clarify accuracy of acute hepatitis C (AHC) and its clinical characteristics. Methods:  We reviewed 632 reported cases from national surveillance data of the Taiwan Center for Disease Control between 1995 and 2004, and reclassified diagnoses. A definite case was defined as alanine aminotransferase (ALT) > 10 × the upper limit of normal (ULN) with seroconversion of anti-hepatitis C virus antibody (anti-HCV). A probable case was defined as (i) seroconversion of anti-HCV and/or elevated ALT levels; or (ii) anti-HCV(+) but titers increased (from  10 × the ULN. A suspected case was defined as initial anti-HCV(+) and ALT level > 10 × the ULN and/or jaundice. Excluded cases were defined as ALT levels less than 10 × ULN with initial positive anti-HCV Ab. Results:  A total of 310 (49%) cases were confirmed as AHC; these included 95 (15%) definite and 215 (34%) probable cases. Higher incidence rates and accuracy of AHC were demonstrated in the southern area significantly if compared with northern, eastern and central areas, respectively (all P < 0.05). On comparison between blood centers and hospitals, more AHC cases were found in Southern Taiwan than in other areas (157/73 vs 24/40, P < 0.001), younger mean age (33.3 ± 11.1 vs 49.3 ± 16.4, P < 0.001), lower ALT levels (263.1 ± 200.9 vs 1264.2 ± 706.8, P < 0.001) and male predominance (191/39 vs 46/18, P = 0.046). Conclusions:  This study showed our reporting system over-estimated the AHC diagnosis, which is also a common issue worldwide. Greater efforts are needed to establish appropriate reporting systems, as well as more supplemental methods to distinguish between prevalent and incident cases.