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HCV in China....Extrahepatic Diseases HCV R.E.V.E.A.L. Study in Taiwan
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HCV has been a notifiable infection in the Hong Kong region of China since 1996; cases are tracked through the Surveillance and Epidemiology Branch of the Centre for Health Protection (28). The use of paid blood donors has been banned in China, but anti-HCV screening reports were not regularly tracked among donation agencies (29).
Risk factors
There were a limited number of risk factor assessments (29-31). A 2009 study on 69 patients from around Anyang found the strongest risk factor to be intravenous (IV) injection, where 75.4% of HCV infections were associated with IV use of glass syringes or needles. A history of blood transfusions was also reported in 73.9% of the cases and was statistically significant after adjustment for other risk factors. An additional significant risk factor was oesophageal balloon use, found in 27.5% of infected individuals. All three risk factors point to under-regulated medical procedures conferring a large risk for HCV transmission (30).
A blood donor study also indicated continued iatrogenic transmission. Risk factor assessments suggested urban, educated individuals who were more likely to see a doctor were at higher risk for HCV, confirming continued transmission in the hospital/medical care-based setting (29).
Prevalence
The estimated HCV prevalence was 1-1.9%. Since 1992, a number of studies reported prevalence within a range of 0.29-9.6% (29, 30, 32-53); however, there were no systematic population-based estimates. Consistent with other countries, blood donor populations provided low prevalence rates because of selection bias. A study in 13 620 volunteer blood donors in one province reported a prevalence of 0.49% in 2003 (29). The prevalence was highest in the 40-49 year olds, at 0.86% (29).
Among non-blood donors, a 1998 study of 3902 individuals from Shenyang province reported a range of 0.42-1.66% (38). Others found a prevalence of 9.6% in 500 elderly individuals (>55 years of age) in the rural Henan province (32), while Liu et al. (30) documented a prevalence of 0.90% in 8226 persons aged 25-65 participating in an endoscopic surveillance study for oesphageal cancer in the Anyang province. In another large study, a prevalence of 1.03% was reported in 12 280 patients admitted to the hospital for a transfusion or other surgical procedure (33).
Diagnosed/incidence
A single incidence study reported a rate of 24.2/100 000 in a sample of 89 647 blood donors in 2007 (54). However, data from other countries suggested that blood donor sampling underestimated the actual incidence rate. Thus, the number of new cases was likely to be higher.
Genotype distribution
Genotype distributions were reported by studies published in 1994-2006 (55-58). A study of 139 HCV patients sampled from nine regions in China (56) reported genotypes 1 (67.6%), 2 (14.4%), 3 (4.3%), 6 (13%) and other (0.7%). Genotype 1b was the most prevalent at 66.2%, and genotype 2a showed a prevalence of 13.7%. Statistically significant geographical differences were observed, and genotype 6 was only observed in the South (56).
A more recent study from Hong Kong sampled 1055 IDUs and non-IDUs in 1998-2004. The non-IDU population showed a genotype 1b prevalence of 63.6%. Genotypes 2a and 3 had prevalence rates of 3.1 and 3.9%, respectively, and genotype 6a was found in 23.6% of participants. The IDU population showed statistically different genotype distributions, where genotype 6a was seen in 58.5% and 1b in 33.0% (55).
Summary
HCV epidemiology in China is largely uncertain. No population-based prevalence or incidence rate estimate is available. Most investigations in HCV have been performed in subgroup studies or voluntary blood donor populations. There is evidence that genotype distribution and prevalence estimates are significantly different across the country, yet prevalence estimates appear relatively low by comparison to other countries in the Asia Pacific region. Historically, blood transfusions and IV injections appear to be the most prominent risk factors. Additional work is required to better understand the level of existing and new HCV infections in China.
Reference: hepatitis C virus epidemiology in Asia, Australia and Egypt....http://www.natap.org/2011/HCV/080611_02.htm
Liver International
8 JUN 2011
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Chronic Hepatitis C Virus Infection Increases Mortality From Hepatic and Extrahepatic Diseases: A Community-Based Long-Term Prospective Study - (R.E.V.E.A.L.)-HCV study
J Infect Dis. (July 2012)
http://www.natap.org/2012/HCV/071912_01.htm
The Risk Evaluation of Viral Load Elevation and Associated Liver Disease/Cancer (R.E.V.E.A.L.)-HCV study is a prospective community-based cohort study in Taiwan
In this community-based cohort study, HCV infection was found to be associated with deaths from hepatic and extrahepatic diseases, particularly for those with detectable serum HCV RNA. It is implied that anti-HCV seropositives should be consulted regarding their elevated risks of both hepatic and extrahepatic diseases. It is also suggested that a serum HCV RNA test with appropriate assay may be helpful to triage HCV-infected patients who need intensive care.
Our findings indicate that anti-HCV seropositives with detectable serum HCV RNA had an elevated mortality from several extrahepatic diseases, whereas the risk for anti-HCV seropositives with undetectable HCV RNA had mortality rates much similar to those seronegative for anti-HCV. This suggests that not only hepatic deaths but also extrahepatic deaths could be decreased in anti-HCV seropositives by clearing the virus with efficient antiviral therapy. Our results strengthen the importance of including an HCV RNA test for anti-HCV seropositives in clinical practice. Anti-HCV seropositives, particularly those with detectable serum HCV RNA, should be encouraged to modify health behaviors, including weight reduction, tobacco cessation, or eating a balanced diet, in order to decrease the risk of cancers, circulatory diseases, and renal diseases.
In this prospective study, HCV infection was associated with an increased mortality from extrahepatic diseases, including circulatory diseases and renal diseases. Chronic HCV infection was associated with an increased (1.4-fold) mortality from circulatory diseases, which was consistent with other reports in Western countries [3, 20]. We have reported that HCV infection was associated with cerebrovascular death after considering for conventional risk factors. The dose-response relationship between serum HCV RNA level and the risk of cerebrovascular death further strengthened the causal association of HCV infection and atherosclerosis [21]. HCV infection may play as a stimulus for atherothrombosis by triggering a cascade of immune and inflammatory responses, either locally within vascular tissue or systematically through inflammatory mediators [22].
Anti-HCV seropositives, particularly anti-HCV seropositives with positive HCV RNA, had an increased risk of dying from renal diseases compared with anti-HCV seronegatives. A large cohort of veterans in the United States found that HCV-infected participants had an increased risk of developing end-stage renal diseases treated with dialysis or renal transplantation [23]. The pathogenesis of HCV-associated renal disease might have resulted from the deposition of circulating immune complexes in the mesangium and subendothelium, which activate the complement system with the proliferation and infiltration of mononuclear phagocytes, enabling the release of protease and oxidants to alter the glomerular permeability [24].
In addition to hepatocellular carcinoma, this study found significant associations between HCV infection and increased mortality from cancers of the esophagus, prostate, and thyroid. A case-control study found an association between HCV and thyroid cancer with a significant odds ratio of 3.3 [13]. Yet, other large-scale prospective studies failed to find the associations [20, 25]. The associations with HCV infection for prostate and esophagus cancer have never been reported previously and need further studies to confirm. Interestingly, all participants who died from these cancers had detectable serum HCV RNA, suggesting that active HCV infection might play a role. By computerized linkage with national cancer registration profiles, we also found that participants with HCV infection had an increased incidence of esophagus, prostate, and thyroid cancers (data not shown). A large veteran cohort indicated that HCV infection conferred a 20%-30% increased risk of non-Hodgkin lymphoma [25]. In this cohort, only 2 cases died from non-Hodgkin lymphoma and no cases died from Hodgkin's lymphoma among anti-HCV seropositives. It was difficult to evaluate the association between HCV infection and lymphoma in this study.
Seroprevalence of hepatitis C, hepatitis B virus and syphilis in HIV-1 infected patients in Shandong, China: HCV/HIV coinfection rate; HCV sexual transmission
Int J STD AIDS September 2012
http://www.natap.org/2012/HCV/100912_01.htm
Prevalence of HCV Viral and Host IL28B Genotypes in China
http://www.natap.org/2011/AASLD/AASLD_76.htm
HCV in China: HCV Viral and Host Genotypes Distribution among Han Ethnic Chinese in China
http://www.natap.org/2012/APASL/APASL_33.htm
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