title: Epidemiology of hepatitis C virus infection among injection drug users in China: systematic review and meta-analysis.
abstract: OBJECTIVE
  Injection drug use (IDU) is the predominant mode of hepatitis C virus (HCV) transmission in China. This paper aims to provide a comprehensive and reliable tabulation of available data on the epidemiological characteristics and risk factors for HCV infection in injection drug users (IDUs) in China to help inform prevention programmes and guide future research.
  
  
  METHODS
  Data from articles and reports according to pre-defined criteria on HCV infection rates among IDUs of different regions, genders, ethnic backgrounds and risk factors (injecting practice, needle sharing, long duration, sex behaviour and co-infection status) were abstracted and pooled by meta-analysis. A systematic review was constructed based on both pooled data and representative viewpoints.
  
  
  METHODS
  Ninety-five percent confidence intervals (CI) of infection rates were calculated using the approximate normal distribution model. Odds ratios and 95% CI were calculated by fixed or random effects models. Publication bias was examined using Begg's test and Egger's test. Data manipulation and statistical analyses were undertaken using STATA 7.0 and RevMan 4.2. Epi Info 3.4.3 was used for map construction.
  
  
  RESULTS
  The pooled prevalence of HCV infection among IDUs in China was 61.4% (95% CI 55.7-67.2%), and the epidemic was most severe in Hubei, Yunnan, Guangxi, Hunan and Xinjiang. No significant difference was found in HCV infection rates between male and female IDUs. A significant association was found between HCV infection and ethnic-minority status. IDUs were 9.24 times more likely to be infected with HCV than non-IDUs, while non-IDUs were more likely to be infected with HCV than members of the general population and other risk populations. There was no significant difference in the risk of HCV infection for needle-sharing IDUs and non-needle-sharing IDUs. A longer duration of IDU was associated with increased HCV prevalence. High-risk sexual practices were strongly associated with drug injection behaviours. Co-infection with human immunodeficiency virus (HIV) greatly increased the probability of HCV infection among IDUs, while the probability of hepatitis B virus infection remained similar for HCV-positive and HCV-negative IDUs in China.
  
  
  CONCLUSIONS
  IDU continues to fuel the HCV/HIV epidemics spreading throughout China. Many pragmatic strategies are being implemented but need further evaluation.
authors.affiliation: Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, No. 140, Hanzhong Road, Nanjing, Jiangsu 210029, PR China.
authors.forename: Xian
authors.initials: X
authors.lastname: Xia
authors.forename: Jun
authors.initials: J
authors.lastname: Luo
authors.forename: Jianling
authors.initials: J
authors.lastname: Bai
authors.forename: Rongbin
authors.initials: R
authors.lastname: Yu
mesh_terms: D002681:China / Q000453:epidemiology; D005260:Female; D016174:Hepacivirus / Q000302:isolation & purification*; D006526:Hepatitis C / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008297:Male; D015819:Substance Abuse, Intravenous / Q000821:virology*