The cascade of care for patients with chronic hepatitis delta in Southern Stockholm, Sweden for the past 30 years.

BACKGROUND AND AIMS: Previous studies have shown suboptimal screening for hepatitis D virus (HDV) among patients with chronic hepatitis B (CHB). This study presents the cascade of care for HDV infection in a major secondary referral centre in Southern Stockholm, Sweden. METHODS: HBsAg+ve patients attending Karolinska University Hospital (KUH) from 1992 to 2022 were identified. The prevalence of anti-HDV and/or HDV RNA positivity, interferon (IFN) therapy and maintained virological responses (MVR) after HDV treatment were assessed. Also, time to anti-HDV testing was analysed in relation to liver-related outcomes with logistic regression. RESULTS: Among 4095 HBsAg+ve persons, 3703 (90.4%) underwent an anti-HDV screening; within a median of 1.8 months (range 0.0-57.1) after CHB diagnosis. This screening rate increased over time, to 97.9% in the last decade. Overall, 310 (8.4%) were anti-HDV+ve, of which 202 (65.2%) were HDV RNA+ve. Eighty-five (42%) received IFN, and 9 (10.6%) achieved MVR at the last follow-up. The predictive factors for anti-HDV screening were Asian origin, diagnosis after the year 2012, HIV co-infection (negative factor) and HBV DNA level < 2000 IU/mL in univariable analysis, while HIV co-infection was the only remaining factor in multivariable analysis. Delayed anti-HDV test >5 years was independently associated with worsened liver-related outcomes (adjusted odds ratio = 7.6, 95% CI 1.8-31.6). CONCLUSION: Higher frequency of HDV screening than previously published data could be seen among CHB patients at KUH in a low-endemic setting. Receiving a delayed screening test seems to be associated with worse outcomes, stressing the need of a strategy for timely HDV diagnosis.

Epidemiology of hepatitis D virus infection in Europe: Is it vanishing?

Co-infection with hepatitis delta virus (HDV) is a challenging health care problem worldwide, estimated to occur in approximately 5%-10% of patients with chronic hepatitis B virus (HBV) infection. While HBV prevalence is decreasing globally, the prevalence of HDV infection is rising in some parts mainly due to injection drug use, sexual transmission and immigration from high endemicity areas. Eastern Europe and the Mediterranean are among the regions with high rates of endemicity for HDV and the immigration from high endemicity areas to Central and Western Europe has changed the HDV epidemiology. We aimed to review the prevalence of HDV infection in Europe. A paucity of publication appears in many European countries. Prevalence studies from some countries are old dated and some other countries did not report any prevalence studies. The studies are accumulated in few countries. Anti-HDV prevalence is high in Greenland, Norway, Romania, Sweden and Italy. Belgium, France, Germany, Spain, Switzerland, Turkey and United Kingdom reported decreasing prevalences. Among cirrhotic HBV patients, Germany, Italy and Turkey reported higher rates of HDV. The studies including centres across the Europe reported that HIV-HBV coinfected individuals have higher prevalence of HDV infection. The immigrants contribute the HDV infection burden in Greece, Italy, and Spain in an increasing rate. Previous studies revealed extremely high rates of HDV infection in Germany, Greece, Italy and Sweden. The studies report a remarkably high prevalence of hepatitis delta among HIV/HBV-coinfected individuals, individuals who inject drugs, immigrants and severe HBV infected patients across Europe. The HDV infection burden still appears to be significant. In the lack of an effective HDV therapy, prevention strategies and active screening of HBV/HDV appear as the most critical interventions for reducing the burden of liver disease related to HDV infection in Europe.

Determinants of worse liver-related outcome according to HDV infection among HBsAg positive persons living with HIV: Data from the ICONA cohort.

OBJECTIVES: We aimed to study hepatitis D virus (HDV) prevalence and risk of progression to severe liver-related events (SLRE) in HBsAg positive people living with HIV (PLWH) in Italy; role of HDV-RNA copy levels, HCV coinfection and nadir CD4 counts were also investigated. METHODS: People living with HIV (PLWH) from Italian Foundation cohort Naïve antiretrovirals (ICONA) with available HBsAg and HDV Ab were enrolled. HBsAg, HDV Ab, HDV-RNA and HDV genotypes were tested. PRIMARY END-POINT: time from first HDV screening to Severe Liver Related Events (SLRE: decompensated cirrhosis, liver transplantation, HCC). Fine-grey regression models were used to evaluate the association of HDV Ab, HDV-RNA, HDV/HCV coinfection, CD4 nadir and outcome. Secondary end-points: time to SLRE or death; HDV Ab and HDV-RNA prevalence. RESULTS: A total of 152/809 (18.8%) HBsAg positive PLWH showed HDV Ab reactivity; 63/93 (67.7%) were HDV-RNA positive. Being male, persons who inject drugs (PWID), HCV Ab positive, with FIB-4 > 3.25 were independent factors of HDV Ab positivity. In a median follow-up of 5 years, 37 PLWH (4.1% at 5-year) developed SLRE and 97 (12.0%) reached the SLRE or death end-point. HDV-RNA positive (independently from HDV-RNA copy level) PLWH had a 4.6-fold (95%CI 2.0-10.5) higher risk of SLRE than HDV negatives. PLWH positive for both HCV Ab and HDV Ab showed the highest independent risk of SLRE (ASHR: 11.9, 95%CI: 4.6-30.9 vs. HCV neg/HDV neg). Nadir CD4 < 200/mL was associated with SLRE (ASHR: 3.9, 95% 1.0-14.5). CONCLUSIONS: One-fifth of the HBsAg positive PLWH harbour HDV infection, and are at high risk of progression to advanced liver disease. HCV contributes to worse outcomes. This population needs urgently effective treatments.

Prevalence of hepatitis D virus infection among patients with chronic hepatitis B infection in a tertiary care centre in Thailand.

Knowledge about the epidemiology of hepatitis D virus (HDV) is essential for effective screening and management. Our study aimed to update the prevalence of HDV infection among patients with hepatitis B virus (HBV) infection at hepatology clinics in Thailand. We enrolled HBV-infected patients from hepatology clinics at King Chulalongkorn Memorial Hospital, Bangkok, Thailand, between June 2022 and November 2023. Demographic, biochemical characteristics, and liver-related complications (LRC), including cirrhosis and hepatocellular carcinoma, were reviewed. The competitive enzyme and chemiluminescence immunoassays were used to detect anti-HDV antibodies. Real-time polymerase chain reaction (RT-PCR) was used to test for HDV RNA in anti-HDV-positive patients. The HDV genotype was identified in detectable HDV RNA samples. Of the 702 enrolled patients, four (0.6%) had positive and equivocal for both anti-HDV tests. Two (50.0%) of the four patients tested positive for HDV RNA and genotype 1 was identified; one had multiple risk factors. Anti-HDV seroprevalence was not significantly different between patients with and without LRC. In conclusion, HDV co-infection is less common in Thailand than globally. Additionally, our study identified genotype 1, the predominant HDV genotype worldwide, and observed co-infection even without LRC.

Impact of hepatitis D reflex testing on the future disease burden: A modelling analysis.

Chronic hepatitis D (CHD) is a severe form of viral hepatitis that leads to liver cirrhosis and hepatocellular carcinoma. CHD is underdiagnosed, and this study aimed to assess the impact of hepatitis D reflex testing in HBsAg-positive individuals in Spain over the next 8 years. Two scenarios were compared: the current situation (7.6% of HBsAg-positive patients tested for anti-HDV) and reflex testing for all positive samples. A decision tree model was designed to simulate the CHD care cascade. Implementing reflex testing would increase anti-HDV detection to 5498 cases and HDV-RNA to 3225 cases. Additionally, 2128 more patients would receive treatment, with 213 achieving undetectable HDV-RNA levels. The cost per anti-HDV case detected would be €132. In the median time of the analysis, liver complications (decompensated cirrhosis, HCC and liver-related deaths) would be reduced by 35%-38%, implying an estimated cost savings of 36 million euros associated with the management of such complications. By 2030, implementing anti-HDV reflex testing would reduce the clinical and economic burden of CHD by 35%-38%.

Hepatitis D: A Review.

Importance: Hepatitis D virus (HDV) infection occurs in association with hepatitis B virus (HBV) infection and affects approximately 12 million to 72 million people worldwide. HDV causes more rapid progression to cirrhosis and higher rates of hepatocellular carcinoma than HBV alone or hepatitis C virus. Observations: HDV requires HBV to enter hepatocytes and to assemble and secrete new virions. Acute HDV-HBV coinfection is followed by clearance of both viruses in approximately 95% of people, whereas HDV superinfection in an HBV-infected person results in chronic HDV-HBV infection in more than 90% of infected patients. Chronic hepatitis D causes more rapidly progressive liver disease than HBV alone. Approximately 30% to 70% of patients with chronic hepatitis D have cirrhosis at diagnosis and more than 50% die of liver disease within 10 years of diagnosis. However, recent studies suggested that progression is variable and that more than 50% of people may have an indolent course. Only approximately 20% to 50% of people infected by hepatitis D have been diagnosed due to lack of awareness and limited access to reliable diagnostic tests for the HDV antibody and HDV RNA. The HBV vaccine prevents HDV infection by preventing HBV infection, but no vaccines are available to protect those with established HBV infection against HDV. Interferon alfa inhibits HDV replication and reduces the incidence of liver-related events such as liver decompensation, hepatocellular carcinoma, liver transplant, or mortality from 8.5% per year to 3.3% per year. Adverse effects from interferon alfa such as fatigue, depression, and bone marrow suppression are common. HBV nucleos(t)ide analogues, such as entecavir or tenofovir, are ineffective against HDV. Phase 3 randomized clinical trials of bulevirtide, which blocks entry of HDV into hepatocytes, and lonafarnib, which interferes with HDV assembly, showed that compared with placebo or observation, these therapies attained virological and biochemical response in up to 56% of patients after 96 weeks of bulevirtide monotherapy and 19% after 48 weeks of lonafarnib, ritonavir, and pegylated interferon alfa treatment. Conclusions and Relevance: HDV infection affects approximately 12 million to 72 million people worldwide and is associated with more rapid progression to cirrhosis and liver failure and higher rates of hepatocellular carcinoma than infection with HBV alone. Bulevirtide was recently approved for HDV in Europe, whereas pegylated interferon alfa is the only treatment available in most countries.

Clinical long-term outcome of hepatitis D compared to hepatitis B monoinfection.

BACKGROUND AND AIMS: Hepatitis D virus (HDV) infection causes the most severe form of chronic viral hepatitis. However, it is still unclear to what extent the underlying cirrhosis may contribute to disease progression. The aim of this study was to compare the long-term outcome of HDV infection with HBV monoinfection in a single-center cohort of both non-cirrhotic and cirrhotic patients. METHOD: We retrospectively studied 175 patients with chronic hepatitis D (CHD) who were followed for at least 6 months (median of 6.3 (0.6-23.6) years). In addition, we selected 175 patients with HBV monoinfection (CHB) who were matched for gender, age, region of origin, HBeAg status, and bilirubin. Liver-related clinical end points were defined as hepatic decompensation (ascites, encephalopathy, variceal bleeding), liver transplantation, HCC, or liver-related death. RESULTS: Clinical complications developed earlier (4.6 vs. 6.2 years) and more frequently (35.4% vs. 12.6%, p < 0.01) in CHD patients. In a multivariate Cox regression, HDV infection was independently associated with the development of end points (p < 0.01; HR: 3.0; 95% CI 1.4-6.4). However, in cirrhotic patients there were no significant differences between HBV and HDV in the development of end points. Besides, CHB patients with cirrhosis developed more frequently HCC (35.5%) than CHD patients with cirrhosis (18.5%). CONCLUSION: Our results confirmed that HDV leads to a faster progression to cirrhosis compared to HBV. However, once cirrhosis is present, not HDV but the underlying cirrhosis is the dominate intrinsic risk factor for the development of liver-related end points and for the progression to HCC.

Management of hepatitis D in general practice.

BACKGROUND: Hepatitis D virus (HDV) requires the presence of hepatitis B virus for replication and infection, and is associated with accelerated progression to cirrhosis and an increased risk of hepatocellular carcinoma. Approximately 4% of Australians living with hepatitis B are infected with HDV, although it is likely that HDV remains underdiagnosed. OBJECTIVE: This paper highlights the importance of screening for HDV in patients living with chronic hepatitis B (CHB) and provides an overview of diagnosis and treatment approaches for general practitioners (GPs), with the hope of reducing preventable liver-related morbidity and mortality in people living with CHB and HDV coinfection. DISCUSSION: The diversity of risk factors and geographical origins of patients in the multicultural Australian populace highlights the need for routine testing for HDV in patients diagnosed with CHB. GPs have a pivotal role in the diagnosis of HDV and should, if possible, promptly refer patients to non-GP specialist physicians to consider HDV therapy.

Hepatitis Delta Infection: A Clinical Review.

First discovered over 40 years ago, the hepatitis delta virus (HDV) is a unique RNA virus, requiring hepatitis B virus (HBV) antigens for its assembly, replication, and transmission. HBV and HDV can be acquired at the same time (coinfection) or HDV infection can occur in persons with chronic HBV (superinfection). Screening guidelines for HDV are inconsistent. While some guidelines recommend universal screening for all people with HBV, others recommend risk-based screening. Estimates of the global HDV prevalence range from 4.5 to 14.6% among persons with HBV; thus, there may be up to 72 million individuals with HDV worldwide. HDV is the most severe form of viral hepatitis. Compared to HBV monoinfection, HDV coinfection increases the risk of cirrhosis, hepatocellular carcinoma, hepatic decompensation, mortality, and necessity for liver transplant. Despite the severity of HDV, there are few treatment options. Pegylated interferon (off-label use) has long been the only available treatment, although bulevirtide is conditionally approved in some European countries. There are many potential treatments in development, but as yet, there are few effective and safe therapies for HDV infection. In conclusion, given the severity of HDV disease and the paucity of treatments, there is a great unmet need for HDV therapies.

EASL Clinical Practice Guidelines on hepatitis delta virus.

Hepatitis D virus (HDV) is a defective virus that requires the hepatitis B virus to complete its life cycle and cause liver damage in humans. HDV is responsible for rare acute and chronic liver diseases and is considered the most aggressive hepatitis virus. Acute infection can cause acute liver failure, while persistent infection typically causes a severe form of chronic hepatitis which is associated with rapid and frequent progression to cirrhosis and its end-stage complications, hepatic decompensation and hepatocellular carcinoma. Major diagnostic and therapeutic innovations prompted the EASL Governing Board to commission specific Clinical Practice Guidelines on the identification, virologic and clinical characterisation, prognostic assessment, and appropriate clinical and therapeutic management of HDV-infected individuals.

HERACLIS-HDV cohort for the factors of underdiagnosis and prevalence of hepatitis D virus infection in HBsAg-positive patients.

BACKGROUND AND AIMS: Hepatitis D virus (HDV) underdiagnosis remains common. We assessed the HDV screening and prevalence rates in HBsAg-positive patients seen at tertiary liver centres throughout Greece as well as factors affecting HDV diagnosis. METHODS: All adult HBsAg-positive patients seen within the last 5 years were included. Non-screened patients who visited or could be recalled to the clinics over a 6-month period were prospectively tested for anti-HDV. RESULTS: Of 5079 HBsAg-positive patients, 53% had anti-HDV screening (41% before and 12% after study initiation). Pre-study (8%-88%) and total screening rates (14%-100%) varied widely among centres. Screening rates were associated with older age, known risk group, elevated ALT, centre location and size and period of first visit. Anti-HDV prevalence was 5.8% without significant difference in patients screened before (6.1%) or after study initiation (4.7%, p = 0.240). Anti-HDV positivity was associated with younger age, parenteral drug use, born abroad, advanced liver disease and centre location. Overall, HDV RNA detectability rate was 71.6% being more frequent in anti-HDV-positive patients with elevated ALT, advanced liver disease and hepatitis B therapy. CONCLUSIONS: Anti-HDV screening rates and recall capabilities vary widely among Greek liver clinics being higher in HBsAg-positive patients of known risk group with active/advanced liver disease seen at smaller centres, while non-medical factors are also important. Anti-HDV prevalence varies throughout Greece being higher in patients born abroad with younger age, parenteral drug use and advanced liver disease. Viremia is more frequently but not exclusively detected in anti-HDV-positive patients with elevated ALT and advanced liver disease.

Hepatitis delta infection among persons living with HIV in Europe.

BACKGROUND AND AIMS: A high prevalence of hepatitis delta virus (HDV) infection, the most severe form of viral hepatitis, has been reported among persons living with HIV (PLWH) in Europe. We analysed data from a large HIV cohort collaboration to characterize HDV epidemiological trends across Europe, as well as its impact on clinical outcomes. METHODS: All PLWH with a positive hepatitis B surface antigen (HBsAg) in the Swiss HIV Cohort Study and EuroSIDA between 1988 and 2019 were tested for anti-HDV antibodies and, if positive, for HDV RNA. Demographic and clinical characteristics at initiation of antiretroviral therapy were compared between HDV-positive and HDV-negative individuals using descriptive statistics. The associations between HDV infection and overall mortality, liver-related mortality as well as hepatocellular carcinoma (HCC) were assessed using cumulative incidence plots and cause-specific multivariable Cox regression. RESULTS: Of 2793 HBsAg-positive participants, 1556 (56%) had stored serum available and were included. The prevalence of HDV coinfection was 15.2% (237/1556, 95% confidence interval [CI]: 13.5%-17.1%) and 66% (132/200) of HDV-positive individuals had active HDV replication. Among persons who inject drugs (PWID), the prevalence of HDV coinfection was 50.5% (182/360, 95% CI: 45.3%-55.7%), with similar estimates across Europe, compared to 4.7% (52/1109, 95% CI: 3.5%-5.9%) among other participants. During a median follow-up of 10.8 years (interquartile range 5.6-17.8), 82 (34.6%) HDV-positive and 265 (20.1%) HDV-negative individuals died. 41.5% (34/82) of deaths were liver-related in HDV-positive individuals compared to 17.7% (47/265) in HDV-negative individuals. HDV infection was associated with overall mortality (adjusted hazard ratio 1.6; 95% CI 1.2-2.1), liver-related death (2.9, 1.6-5.0) and HCC (6.3, 2.5-16.0). CONCLUSION: We found a very high prevalence of hepatitis delta among PWID across Europe. Among PLWH who do not inject drugs, the prevalence was similar to that reported from populations without HIV. HDV coinfection was associated with liver-related mortality and HCC incidence.

Hepatitis D virus interferes with hepatitis B virus RNA production via interferon-dependent and -independent mechanisms.

BACKGROUND & AIMS: Chronic coinfection with HBV and HDV leads to the most aggressive form of chronic viral hepatitis. Herein, we aimed to elucidate the molecular mechanisms underlying the widely reported observation that HDV interferes with HBV in most coinfected patients. METHODS: Patient liver tissues, primary human hepatocytes, HepaRG cells and human liver chimeric mice were used to analyze the effect of HDV on HBV using virological and RNA-sequencing analyses, as well as RNA synthesis, stability and association assays. RESULTS: Transcriptomic analyses in cell culture and mouse models of coinfection enabled us to define an HDV-induced signature, mainly composed of interferon (IFN)-stimulated genes (ISGs). We also provide evidence that ISGs are upregulated in chronically HDV/HBV-coinfected patients but not in cells that only express HDV antigen (HDAg). Inhibition of the hepatocyte IFN response partially rescued the levels of HBV parameters. We observed less HBV RNA synthesis upon HDV infection or HDV protein expression. Additionally, HDV infection or expression of HDAg alone specifically accelerated the decay of HBV RNA, and HDAg was associated with HBV RNAs. On the contrary, HDAg expression did not affect other viruses such as HCV or SARS-CoV-2. CONCLUSIONS: Our data indicate that HDV interferes with HBV through both IFN-dependent and IFN-independent mechanisms. Specifically, we uncover a new viral interference mechanism in which proteins of a satellite virus affect the RNA production of its helper virus. Exploiting these findings could pave the way to the development of new therapeutic strategies against HBV. IMPACT AND IMPLICATIONS: Although the molecular mechanisms remained unexplored, it has long been known that despite its dependency, HDV decreases HBV viremia in patients. Herein, using in vitro and in vivo models, we showed that HDV interferes with HBV through both IFN-dependent and IFN-independent mechanisms affecting HBV RNA metabolism, and we defined the HDV-induced modulation signature. The mechanisms we uncovered could pave the way for the development of new therapeutic strategies against HBV by mimicking and/or increasing the effect of HDAg on HBV RNA. Additionally, the HDV-induced modulation signature could potentially be correlated with responsiveness to IFN-α treatment, thereby helping to guide management of HBV/HDV-coinfected patients.

What does quantitative HBsAg level mean in chronic hepatitis D infection?

OBJECTIVE: In hepatitis delta virus (HDV) infection, which is an important etiological cause of chronic liver disease, the relationship between serum quantitative HBsAg level and fibrosis and histological activity was investigated. METHODS: Between 2014 and 2020, 98 patients with chronic HDV infection (53 noncirrhotic, 45 cirrhotic) participated in this prospectively designed study. Quantitative HBsAg levels of the patients were measured and their relationship with the stage of chronic liver disease was compared with histological activity index (HAI), fibrosis score and HDV RNA, model for end-stage liver disease score and other biochemical parameters. RESULTS: All patients were infected with genotype 1 (100%). HBeAg was positive in 8 (8.1%) of the patients. A correlation was found between quantitative HBsAg level and HDV RNA level in patients with both cirrhotic (r = 0.568; P < 0.001) and noncirrhotic (r = 0.644; P < 0.001) HDV infection. Alanine transaminase (P = 0.001; r = 0.495) and aspartate transaminase (P = 0.001; r = 0.511) levels correlated with quantitative HBsAg levels, more prominently in noncirrhotic patients. There was a correlation between quantitative HBsAg level and histological activity index (HAI) in patients with noncirrhotic HDV infection (P < 0.001; r = 0.664). In receiver operating characteristic analysis, both quantitative HBsAg (for cutoff: 1000; sensitivity 76%; specificity 17%; P = 0.335) and HDV RNA (for cutoff: 100000; sensitivity 2%; specificity 98%; P = 0.096) were not predictive markers for cirrhosis. CONCLUSION: Quantitative HBsAg level can be evaluated as an indicator of viral replication and histological activity in patients with chronic delta hepatitis without cirrhosis. We think that quantitative HBsAg level will be useful in the management of chronic HDV infection, especially in noncirrhotic patients.

Treatment of hepatitis delta and HIV infection.

Hepatitis delta virus (HDV) is a defective agent that only infects individuals with hepatitis B virus (HBV). Around 5-10% of chronic hepatitis B patients worldwide are superinfected with HDV, which means 15-25 million people. Hepatitis delta is the most severe of all chronic viral hepatitis, leading to cirrhosis, liver cancer and/or transplantation in most patients. Despite it, many HDV patients remain undiagnosed. The only treatment available until recently was peginterferon alfa, with poor results and significant side effects. The recent approval of bulevirtide, a lipopeptide that blocks HBV/HDV entry, has revolutionized the field. Another drug, lonafarnib, already approved to treat progeria, is expected to be available soon as HDV therapy. Since there is no cell reservoir for the HDV RNA genome, hypothetically viral clearance could be achieved if complete blocking of viral replication occurs for a minimum time frame. This is what happens in hepatitis C using direct-acting antivirals, with the achievement of cure in nearly all treated patients. We envision the cure of hepatitis delta using combination antiviral therapy. Given that sexual and parenteral transmission routes are the most frequent for the acquisition of HBV and HDV, shared with HIV infection and HBV/HDV and HIV coinfection. The clinical outcome of hepatitis delta is worst in the HIV setting, with more frequent liver complications. Since most persons infected with HIV are on regular health care follow-up, we propose that HIV-HDV patients should be prioritized for moving forward new and potentially curative treatments for hepatitis delta.

Natural history of untreated HDV patients: Always a progressive disease?

A severe course has been described in early studies on chronic hepatitis D (CHD), with faster pace towards liver cirrhosis with subsequent high liver-related morbidity and mortality in the majority of patients. Earlier studies have included risk groups as people using intravenous drugs (PWID) or those with multiple co-morbidities. During the last decade, the epidemiological landscape of CHD has changed with domestic cases decreasing while increasing cases of CHD consisting of younger persons immigrating from endemic regions to low-endemic regions. Recently, further insights into the spectrum of the disease with an indolent disease course in a substantial proportion of persons with CHD have been gained. At diagnosis, ≥30%-50% had already established liver cirrhosis. Older age, liver cirrhosis, co-infection with HIV and lack of interferon (IFN) therapy are the main predictors of worse clinical outcome. The newly introduced and upcoming antivirals against CHD are highly anticipated, considering the historically low virological response rates to antiviral therapy. Further knowledge is needed to fully comprehend the natural course and the spectrum of this severe form of viral hepatitis. This is also to be able to evaluate the long-term effects of the new antivirals on disease progression.

Seroprevalence and clinical outcome of hepatitis D infection in Qatar.

Background: Worldwide, 5-10% of people with chronic hepatitis B virus infection are co-infected with hepatitis D virus. In Qatar, there are no data on hepatitis D virus infection among patients positive for hepatitis B surface antigen (HBsAg). Aims: To determine the seroprevalence of hepatitis D virus infection among patients with chronic hepatitis B virus infection in Qatar and assess the characteristics of these patients. Methods: This was a retrospective cohort study of all HBsAg-positive individuals tested for hepatitis D virus between 1 January 2010 and 29 December 2019 within the Hamad Medical Corporation. Data were retrieved from electronic records and included demographic and clinical information of the patients. Results: Of the 2348 HBsAg-positive patients, 125 were positive for hepatitis D virus (seroprevalence 5.3%). The median age of hepatitis D positive patients was significantly higher than for hepatitis D negative patients (P = 0.001). Most of the patients with hepatitis D had a hepatitis B viral load < 2000 IU/mL (53.6%) and were negative for hepatitis B e antigen (93.6%). A significantly greater proportion of hepatitis D positive patients than hepatitis D negative patients were infected with hepatitis C virus (P < 0.001), and had liver cirrhosis (P < 0.001) and hepatocellular carcinoma (P = 0.006). Conclusions: Hepatitis D virus infection is associated with lower hepatitis B virus viraemia and more advanced liver disease in the study population.