Short summary

This study will systematically review the litterature and perform a meta-analysis on the prevalence of Hepatitis C Virus among people with mental illness. Both published and unpublished data will be accepted. Articles which report HCV prevalence in a population of patients with psychiatric illness will be included. Secondary objectives will include estimating HCV prevalence with subpopulations (diagnosis, gender etc). Data pertaining to the study's objective will be extracted and pooled based on continent, and all included articles as well as the cumulative data will be quality assessed.

Rationale

With an estimated 71 million people infected worldwide, Hepatitis C Virus (HPC) remains a frequent cause of liver cirrhosis, hepatocellular carcinoma and ultimately death. However, with the advent of well-tolerated and highly effective direct acting antiviral therapy (DAA), the vast majority of patients can now be cured. This has led WHO to establish ambitious targets of eliminating HCV as a public health threat by 2030. As the effective treatment leads to a rapid emptying of the pool of known HCV patients, the main obstacle towards achieving these targets has now become diagnosing enough new patients to maintain the necessary treatment rates.

Given the relatively asymptomatic state of early HCV infection, timely diagnosis and treatment relies on screening. Ideally, screening strategies should be based on local epidemiology where possible. Additionally, populations at increased risk of infection should be targeted.

Thus, in order to inform future HCV screening efforts, prevalence studies are essential. To date, these have mainly been done in high-risk populations such as IV-drug users or prison inmates, whereas other potential risk groups such as people with severe mental illness (SMI) have been less studies. However, if the 2030 targets are to be reaches, screening efforts should be intensified in all populations at increased risk of infection.

In 2016, a systematic review on HCV prevalence among people with SMI found an increased prevalence in this population. However, reported prevalence estimates varies greatly between geographical locations, and limited locations were represented (for example 4 out of 6 European studies were from Italy). Furthermore, HCV prevalence estimates were not reported corresponding to psychiatric subpopulations (schizophrenia, bipolar disorder etc), nor were potential predictors of HCV infection among people with SMI assessed.

Due to these limitations in the above review, we wish to perform an updated review on HCV prevalence among people with SMI. Knowing that HCV prevalence can vary widely, studies covering new locations are necessary to gain a more comprehensive understanding of the burden of HCV in this population. Also, to allow for better risk assessment of the individual patient, we intend to (if data permits) conduct a meta-analysis of HCV prevalence among psychiatric subpopulations and assess predictors of HCV infection among people with SMI.

The above-mentioned review mainly included studies from the era of interferon-based treatment, a treatment which was often contraindicated for people with SMI. We believe that the introduction of well-tolerated DAAs may have prompted new research efforts in this area, thus providing the foundation for a more comprehensive update.

Description of the cohort

Articles that describe the prevalence of Hepatitis C Virus in adults (>15 yo) with mental illness such as schizophrenia, schizoaffective disorders, non-affective psychosis, bipolar disorder, anxiety disorders, ADHD with personality disorders, according to recognized diagnostic criteria (e.g. ICD, DSM) will be included.

Data and biological material

Data collection from the included articles will fall into 3 categories:

1) Administrative article data: Data points such as author, year of publication, country of publication, etc.

2) Outcome related variables: Data points that answer the research question. For example: study design, setting of the study, a definition of the studied population (including psychiatric sub-populations and risk factors), prevalence estimates of HCV and measurement methods, etc.

3) Quality assessment data: Data points to assess the quality of the individual articles, such as sample size, method of participant recruiting, description of the study population, methods of identification of HCV, statistical analysis used.

Collaborating researchers and departments

Department of Infectious Diseases, Odense University Hospital

• Medical Student, Jessica Wentworth
• MD, PhD, Stephanie Bjerrum

Department of Clinical Microbiology, Aarhus University Hospital

• PhD-student, MD, Martin Petri Bækby