Hepatitis C (HCV) and HIV are global public health concerns. By the end of 2014 in Canada, an estimated 230,000–450,000 (0.66%–1.3%) individuals were infected with HCV and about 75,500 were living with HIV.
Both HCV and HIV are associated with significant morbidity and mortality. Social conditions and other infections (e.g. addictions, mental illness, HBV, TB and STIs) that affect infection risk and disease progression are common in people with HIV/HCV. At the broader population level, there is limited data and research on the distribution and evolution of these co-occurring and predisposing conditions.
This research was conducted to inform the delivery of integrated services for various groups of people, according to their specific needs, based on multiple co-occurring conditions and infections.
Using a large population-based cohort (the BC Hepatitis Testers Cohort (BC-HTC)), researchers at the BC Centre for Disease Control and University of British Columbia examined the impact of mental illness, substance use and social disparities on the evolution of HIV and HCV infections in BC from 1990-2013.
The BC-HTC includes all individuals tested for HCV or HIV at the BCCDC Public Health Laboratory, or reported to public health as a confirmed case of HCV, Hepatitis B (HBV), HIV/AIDS or active TB. This cohort is linked with provincial healthcare administrative databases including medical visits, hospitalizations, prescription drugs, cancers and deaths.
For this study, HCV and HIV testers were classified into five combinations:
- not tested for HIV or HCV or tested negative for HCV and HIV (HIV-/HCV-),
- HIV mono-infected (HIV+/HCV-),
- prevalent HCV (HIV-/HCV+prevalent),
- HCV seroconverters (HIV-/HCV+seroconverters), and
- HIV-HCV co-infected (HIV+/HCV+ co-infected).
We described the distribution of characteristics of HCV, HIV, and co-infected groups overall and by time periods for stratified analyses (<2000, 2000-2004, 2005-2009 and 2010-2013). We constructed statistical models measuring associations of various factors with four positive categories for HIV and HCV infections: HIV mono-infected, HIV-HCV co-infected, HCV seroconverters and HCV prevalent compared to the one negative category (HIV-/HCV-).
Of 1.37 million eligible individuals, 4.1% were HCV prevalent, 0.5% HIV mono-infected, 0.3% HIV-HCV co-infected and 0.5% were HCV seroconverters.
Overall, HIV mono-infected individuals lived in urban areas (92%), had low injection drug use (IDU) (4%) and problematic alcohol use (4%), and were materially more privileged than other groups. HIV-HCV co-infected and HCV seroconverters were materially most deprived (37%, 32%), had higher IDU (28%, 49%) and problematic alcohol use (14%, 17%), and major mental illnesses (12%, 21%). IDU, opioid substitution therapy, and material deprivation increased in HCV seroconverters over time.
In statistical models, over time, the odds of IDU declined among HCV prevalent and HIV mono-infected individuals but not in HCV seroconverters. Declines in odds of problematic alcohol use were observed in HCV seroconverters and HIV-HCV co-infected individuals over time.
In summary, co-occurrence and confluence of substance use, mental illnesses, co-infections and socioeconomic disparities was found and varied across HIV and HCV infection groups. Most vulnerable groups were HCV seroconverters and HIV-HCV co-infected individuals who were mainly people who inject drugs.
Implications for practice
Co-occurrence and syndemics of infections and social conditions require integration of testing, care, treatment and support services for infections, substance use and mental illness. Groups like HCV seroconverters and HIV-HCV coinfected individuals may require more services than HCV prevalent and HIV mono-infected individuals.
Results of this study may be used to inform guidelines for HIV testing and HCV screening, and to define settings for integrated care where a range of prevention and treatment services could be offered in a single sitting.
This study supports the value of monitoring trends of substance use, social disparities, mental health disorders and comorbidities in HIV and HCV testers, as well as evaluating screening and disease prevention strategies.
For more information, please contact Dr. Zahid Butt.
Co-authors on this work were: Nabin Shrestha, Margot Kuo, Dionne Gesink, Mark Gilbert, Jason Wong, Amanda Yu, Maria Alvarez, Hasina Samji, Jane Buxton, James C. Johnston, Victoria J. Cook, David Roth, Theodora Consolacion, Michelle Murti, Gina Ogilvie, Robert Balshaw, Mark Tyndall, Mel Kradjen and Naveed Z. Janjua.