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

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.

The Population Level Cascade of Care for Hepatitis C in British Columbia, Canada: The BC Hepatitis Testers Cohort (BC-HTC)

“…This raises multiple issues: bias towards underestimating prevalence in those less engaged in healthcare, and potential misclassification related to sensitivity and specificity of these measures. Potentially lower linkage rates in vulnerable groups would result in less representation of homeless, street-involved, and incarcerated individuals (Janjua et al, 2016a). …”

“…The BC-HTC construction and data linkage has been described elsewhere (Janjua et al, 2016a, Janjua et al, 2016b). Briefly, the BC-HTC includes all individuals tested for HCV or HIV, or reported as a case of HBV, HCV, HIV or active tuberculosis (TB) in BC between 1990 and 2013 linked with data on medical visits, hospitalizations, cancers, prescription drugs, and deaths (BC Vital Statistics Agency, 2014, British Columbia Ministry of Health, 2014a, British Columbia Ministry of Health, 2014b, British Columbia Ministry of Health, 2014c, British Columbia Ministry of Health, 2014d, British Columbia Ministry of Health, 2014e).…”

Effect of opioid-substitution therapy and mental health counseling on HIV risk among hepatitis C-infected individuals

“…All prescriptions dispensed in BC are recorded in a centralized system called PharmaNet, irrespective of the payer. Detailed characteristics of the cohort, including linkage and related data, are presented elsewhere 15,16. Data linkages were approved by the data stewards of the BCCDC, BCCDC-PHL, BC Ministry of Health, BC Vital Statistics Agency, and BC Cancer Registry.…”

“…Approval for data linkage with the Ministry of Health data sets was granted under the BCCDC public health mandate to conduct surveillance and program evaluation. Data were deidentified before analyses 15. This study was approved by the Behavioral Research Ethics Board (H15-01776) at the University of British Columbia.…”

The 5th Canadian Symposium on Hepatitis C Virus: We Are Not Done Yet—Remaining Challenges in Hepatitis C

“…Krajden (University of British Columbia, Vancouver, Canada) moderated the panel discussion entitled: “From Research to Action: How to Translate Research into Policy Change” [53]. He opened by presenting data from the British Columbia Hepatitis Testers Cohort (BC-HTC) highlighting that the overall mortality for anti-HCV positive individuals was about 2.5-fold higher than in those who tested anti-HCV negative [54]. A key element is that both mortality and related health costs were the result of HCV acquisition risks and the sequelae of chronic HCV infection.…”