Assessing Hepatitis C Burden and Treatment Effectiveness through the British Columbia Hepatitis Testers Cohort (BC-HTC): Design and Characteristics of Linked and Unlinked Participants.

Naveed Zafar Janjua,Mei Chong,Margot Kuo,Amanda Yu,Mark W Tyndall,Mel Krajden,Rosemary Armour,Maria Alvarez,Seyed Ali Mussavi Rizi,Jason Wong,Ciaran Aiken,David Godfrey,Karen Li,Ryan Woods,Mark Gilbert,Darrel Cook

doi:10.1371/journal.pone.0150176

Abstract

BackgroundThe British Columbia (BC) Hepatitis Testers Cohort (BC-HTC) was established to assess and monitor hepatitis C (HCV) epidemiology, cost of illness and treatment effectiveness in BC, Canada. In this paper, we describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals.MethodsThe BC-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV), HIV or active tuberculosis (TB) in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers. The cohort includes data since inception (1990/1992) of each database until 2012/2013 with plans for annual updates. We computed linkage rates by year and compared the characteristics of linked and unlinked individuals.ResultsOf 2,656,323 unique individuals available in the laboratory and surveillance data, 1,427,917(54%) were included in the final linked cohort, including about 1.15 million tested for HCV and about 1.02 million tested for HIV. The linkage rate was 86% for HCV tests, 89% for HCV cases, 95% for active TB cases, 48% for HIV tests and 36% for HIV cases. Linkage rates increased from 40% for HCV negatives and 70% for HCV positives in 1992 to ~90% after 2005. Linkage rates were lower for males, younger age at testing, and those with unknown residence location. Linkage rates for HCV testers co-infected with HIV, HBV or TB were very high (90–100%).ConclusionLinkage rates increased over time related to improvements in completeness of identifiers in laboratory, surveillance, and registry databases. Linkage rates were higher for HCV than HIV testers, those testing positive, older individuals, and females. Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV.

Highlights

Hepatitis C virus (HCV) is a major global public health problem with ~184 million people infected worldwide
The British Columbia (BC)-HTC includes all individuals tested for HCV and/or HIV or reported as a case of HCV, hepatitis B (HBV), HIV or active tuberculosis (TB) in BC linked with the provincial health insurance client roster, medical visits, hospitalizations, drug prescriptions, the cancer registry and mortality data using unique personal health numbers
Data from the cohort provide essential information to support the development of prevention, care and treatment initiatives for those infected with HCV

Summary

Introduction

Hepatitis C virus (HCV) is a major global public health problem with ~184 million people infected worldwide. In Canada, between 230,000–450,000 (0.66% -1.3%) people are infected with HCV [1]. Short-course, well-tolerated direct acting antiviral therapies are highly effective (95%) in curing HCV but are very expensive [2,3,4,5,6]. Accurate and up-todate knowledge about the current and future burden of disease, co-infections with HIV and HBV, health disparities, and cost of HCV-related illness relative to the cost and effectiveness of treatment are needed to inform public funding decisions for the newer antiviral drug therapies; the need for population level screening; and to prioritize resources for engaging infected individuals into care and treatment. The British Columbia (BC) Hepatitis Testers Cohort (BC-HTC) was established to assess and monitor hepatitis C (HCV) epidemiology, cost of illness and treatment effectiveness in BC, Canada. We describe the cohort construction, data linkage process, linkage yields, and comparison of the characteristics of linked and unlinked individuals.

Methods

Results

Conclusion