Cross-year duplicate reports of chronic hepatitis B in Tianjing

Objective The study was conducted to analyze the number of cross-year duplicates of previously recorded chronic hepatitis B cases and its impact on the reported incidence, in order to standardize the criteria for the reporting of chronic hepatitis. Methods Microsoft Excel was used to pretreat the database of Tianjing's hepatitis B epidemic maintained by the National Disease Surveillance Report Management System. Duplicate records were checked in accordance with three main fields, I.e. patient's name, gender and age. To specify duplicate records, these criteria were followed: 1. Identical name and gender, difference of age 3 years; 2. Names were homonym of different characters; for others, ditto. The first three characters of the name field were respectively extracted into three cells, to which additional cells containing each character's Chinese pinyin were appended. Age values were converted into numeric type. A meta-analysis was eventually performed based on the query function of Access, intergroup differences analyzed using Chi-square analysis. Results The cumulative duplicate rate of chronic hepatitis B cases reported from Jan. to Apr. in 2007 was 28.76%(700/2434) compared with the data in 2004, 2005 and 2006, the respective annual rate being 6.57%, 11.79% and 17.09%. For entries with identical name and gender and similar age, the cumulative duplicate rate was 24.24%; for entries with homonymic name of different characters, the cumulative duplicate rate was 4.52%. The duplicate rate of two-character names (10.65%) was higher than that of three-character names (3.37%), with statistically significant difference(x2= 39.827, P0.01). The increase of the incidence rate reported in 2007 was 32% higher than the increase of the reported incidence rate in the same period, 2006 due to these duplicates(cross-year duplicate reports). Conclusion Established criteria for the reporting of chronic hepatitis are top-priority required.