Incidence analyses and space-time cluster detection of hepatitis C in Fujian Province of China from 2006 to 2010

Abstract

Background: There is limited epidemiologic information about the incidence of hepatitis C in China, and few studies have applied space-time scan statistic to detect clusters of hepatitis C and made adjustment for temporal trend and relative risk of regions.

Methodology and principal findings: We analyzed the temporal changes and characteristics of incidence of hepatitis C in Fujian Province from 2006 through 2010. The discrete Poisson model of space-time scan statistic was chosen for cluster detection. Data on new cases of hepatitis C were obtained from the Center for Disease Control and Prevention of Fujian Province. Between 2006 and 2010, there was an annualized increase in the incidence of hepatitis C of 23.0 percent, from 928 cases (2.63 per 100,000 persons) to 2,180 cases (6.01 per 100,000 persons). The incidence among women increased more rapidly. The cumulative incidence showed that people who were over 60 years had the highest risk to suffer hepatitis C (52.51 per 100,000 persons), and women had lower risk compared to men (OR=0.69). Putian had the highest cumulative incidence among all the regions (86.95 per 100,000 persons). The most likely cluster was identified in Putian during March to August in 2009 without adjustment, but it shifted to three contiguous cities with a two-month duration after adjustment for temporal trend and relative risk of regions.

Conclusions/significance: The incidence of hepatitis C is increasing in Fujian Province, and women are at a more rapid pace. The space-time scan statistic is useful as a screening tool for clusters of hepatitis C, with adjustment for temporal trend and relative risk of regions recommended.

Figure 1. Number of cases of hepatitis C in Fujian Province of China, from 2006 to 2010.

Figure 2. Age and sex distribution of hepatitis C in Fujian Province of China, from 2006 to 2010.

Figure 3. Incidence of hepatitis C in Fujian Province of China, from 2006 to 2010.

Points represent the number of cases per 100,000 persons, and error bars the 95% confidence interval.

Figure 4. The number of cases of hepatitis C in regions identified as the clusters after adjustment for temporal trend and relative risk of regions, with the signal duration marked.