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Open Access Research article

Mortality among British Columbians testing for hepatitis C antibody

Amanda Yu12, John J Spinelli23, Darrel A Cook1, Jane A Buxton12 and Mel Krajden14*

Author Affiliations

1 BC Centre for Disease Control, 655 West 12th Avenue, Vancouver, BC, V5Z 4R4, Canada

2 School of Population & Public Health, University of British Columbia, Vancouver, BC, Canada

3 BC Cancer Agency, Vancouver, BC, Canada

4 Department of Pathology & Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada

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BMC Public Health 2013, 13:291  doi:10.1186/1471-2458-13-291

Published: 2 April 2013

Abstract

Background

Hepatitis C virus (HCV) infection is a major preventable and treatable cause of morbidity and mortality. The ability to link population based centralized laboratory HCV testing data with administrative databases provided a unique opportunity to compare mortality between HCV seronegative and seropositive individuals. Through the use of laboratory testing patterns and results, the objective of this study was to differentiate the viral effects of mortality due to HCV infection from risk behaviours/activities that are associated with acquisition of HCV infection.

Methods

Serological testing data from the British Columbia (BC) Centre for Disease Control Public Health Microbiology and Reference Laboratory from 1992–2004 were linked to the BC Vital Statistics Agency death registry. Four groups of HCV testers were defined by their HCV antibody (anti-HCV) testing patterns: single non-reactive (SNR); serial multiple tested non-reactive (MNR); reactive at initial testing (REAC); and seroconverter (SERO) (previously seronegative followed by reactive, a marker for incident infection). Standardized mortality ratios (SMRs) were calculated to compare the relative risk of all cause and disease specific mortality to that of the BC population for each serological group. Time dependent Cox proportional hazard regression was used to compare hazard ratios (HRs) among HCV serological groups.

Results

All anti-HCV testers had higher SMRs than the BC population. Referent to the SNR group, the REAC group had higher risks for liver (HR: 9.62; 95% CI=8.55-10.87) and drug related mortality (HR: 13.70; 95% CI=11.76-16.13). Compared to the REAC group, the SERO group had a lower risk for liver (HR: 0.53; 95% CI=0.24-0.99), but a higher risk for drug related mortality (HR: 1.54; 95% CI=1.12-2.05).

Conclusions

These findings confirm that individuals who test anti-HCV positive have increased mortality related to progressive liver disease, and that a substantial proportion of the mortality is attributable to drug use and risk behaviours/activities associated with HCV acquisition. Mortality reduction in HCV infected individuals will require comprehensive prevention programming to reduce the harms due to behaviours/activities which relate to HCV acquisition, as well as HCV treatment to prevent progression of chronic liver disease.

Keywords:
Hepatitis C virus; Mortality; Chronic hepatitis; Injection drug use; Data linkage