HDV-Europe: Prevalence and Outcome of HDV in HIV/HBV Coinfection
The aim of this project is to set up a cross-sectional cohort study (France, Germany, The Netherlands, Poland, Spain, Switzerland, Italy, United Kingdom and Portugal) to assess the implementation of EACS guidelines for HDV-testing among PLWH with positive HbsAg and thereby evaluate the prevalence of HDV infection among HIV/HBV-coinfected in 2023, as well as corresponding risk factors. In addition to the testing itself, this study will also set up a cohort and databasee for future HDV studies among PLWH, including clinical, virological und laboratory parameters.

Analyze the rate of HDV-testing and evaluate the prevalence of HDV-infection by testing.

Evaluation of former screening of HDV by assessing existing data at study sites.
Determination of the HDV prevalence in European PLWH and HBV coinfection.

Setting up a database of all PLWH with HBV/HDV coinfection

Analysis of transmission risk factors for HDV coinfection
Asses the rate of HDV positive patients with ongoing HDV replication.
Define the liver disease state by APRI score, fibroscan, ultrasound and routine laboratory test results.
- EligibilityCriteria: Inclusion Criteria:Documented HIV-infection with current Hepatitis B infection, who are serological positive for HBSAg Both, HIV- and HBV Infection must be confirmed by HIV ELISA and HBV HBsAg-testing (2 measurements of positive HBsAg > 6month interval).The viral load results will be included into the analyses, but are not part of the inclusion criteria.  As patients are enrolled retrospectively, data on liver enzymes (transaminases, gamma GT, AP, bilirubin) and viral load will be available, though this is not compulsory. Written informed consent will be provided prior to inclusion, or, if adequate, used from pre-exisitng cohort studies.  -  Exclusion Criteria:  3.2. Exclusion-Criteria PLWH with a cleared HBV-infection will be considered as HIV-monoinfected persons.Individuals younger than 18 years of age will be excluded from the analysis. Patients with any social condition or living circumstances which may interfere with the conduct of the study, as anticipated by the investigator, such as incapacity to adequately understand the study content or not willing to cooperate will be excluded from the study. For France, patients without adequate social security will be excluded.  - - HealthyVolunteers: No - Gender: All - MinimumAge: 18 Years - StdAgeList: Adult, Older Adult - StudyPopulation: To secure representative data, each cohort or clinic network will aim to enroll a sample size of at least 20% of all HIV/HBV-coinfected individuals in each country. The overall number of participants is planned to reach at least 8000 HIV/HBV-coinfected persons. With an estimated 800.000 PLWH in the following 9 countries: Spain 150.00, France 190.000, Germany 93.000, England 106.000, Portugal 61.000, Italy 140.000, Poland 20.000, Switzerland 16.000, Netherlands 24.000, and an estimated HBV-Prevalence of 5%, this would lead to a cohort of around 40.000 HIV/HBV coinfected individuals. According to current data, 20% of HIV/HBV-coinfected PLWH are expected to have an HDV-infection, which should add up to 8000 individuals that would be needed to be studied. - SamplingMethod: Probability Sample