Intern Med J. 2013 Oct;43(10):1081-7.

Hepatitis D virus in Victoria 2000-2009.

Shadur B, MacLachlan J, Cowie B.

B. Shadur1, J. MacLachlan 1,2 and B. Cowie 1,2,3

1WHO Regional Reference Laboratory for Hepatitis B, Victorian Infectious Disease Reference Laboratory;
2Department of Medicine, University of  Melbourne;
3Victorian Infectious Diseases Service, Royal Melbourne Hospital, Melbourne, Victoria, Australia

 

ABSTRACT:

Background: Hepatitis D virus (HDV) coinfection can adversely affect prognosis and complicate management of chronic hepatitis B. The epidemiology and clinical practices surrounding HDV in Australia are poorly understood, with no robust estimates of the burden of disease, and the extent of appropriate testing and clinical follow up is unknown.

Aims: To determine the number of reported cases of HDV in Victoria, Australia between 2000–2009 and to explore screening practices in patients at risk of HDV infection over the same time period.

Methods: Data regarding HDV diagnoses in Victoria for 2000–2009 were obtained from notifiable disease surveillance and public health laboratory testing records. Notifications data were analysed to determine risk factors and demographics of HDV diagnoses where  available, and laboratory records used to determine screening practices and follow up testing.

Results: Eighty-seven notifications for HDV were recorded between 2000 and 2009. The median age at diagnosis was 34 (interquartile range 27–44), and the majority of cases were men (77%) and born overseas (71.4% of those with country of birth reported). During the same period, 2314 Victorian residents were tested for HDV infection, with 110 (4.75%) found to be positive. Both the number of people testing positive and the number of tests conducted steadily increased between 2005 and 2009. Of those patients with positive HDV antibody results, less than half (44 patients, 40%) were subsequently evaluated for replicative infection by polymerase chain reaction.

Conclusion: The number of people being tested for HDV has increased over the past decade; however, gaps in the appropriate follow-up of infected patients are apparent. Birth overseas has become an increasingly important risk factor in Victorian notifications, highlighting the need for routine testing of people living with chronic hepatitis B for HDV infection.

© 2013 The Authors; Internal Medicine Journal © 2013 Royal Australasian College of Physicians.

KEYWORDS: Victoria, epidemiology, hepatitis D, testing protocol

PMID: 23869436

 

SUPPLEMENT:

The epidemiology of hepatitis D virus (HDV) and the impact of HDV infection are often poorly understood and underappreciated (Ref.1). 1 Our study aimed to assess the number of detected HDV cases and the number of notified cases in Victoria, Australia between the years 2000-2009. We also investigated the specific HDV detection tests requested by clinicians (polymerase chain reaction, HDV-antibody, or HDV antigen), the demographics of those affected with HDV, and the time lag between detection of HDV infection and reporting to Victorian Department of Health.

We found that testing for HDV co-infection in patients with hepatitis B virus (HBV) is not performed in a systematic manner. Between the years 2000-2009, 2591 HDV serology tests were performed on 2314 Victorians, and 227 HDV PCR tests were carried out on 161 individuals. This indicates that many patients underwent repeat testing which was likely unnecessary. Importantly, of the 110 serology positive individuals, less than half (44 patients, 40.0%) had a record of subsequent PCR testing to evaluate viral replicative status. This is particularly worrisome given the impact of HDV replication on chronic HBV infection and its management. Conversely, less than half of patients sent for PCR testing had prior HDV serology performed, which also goes against current testing guidelines (Ref.2). Indeed, over the 10-year study period, not one individual was serologically negative but PCR positive. The proportion tested for PCR with no serological evidence of infection increased over time, from just under half (48.0%) of those evaluated using PCR between 2000 and 2004 to the vast majority (81.8%) of those tested between 2005 and 2009.

Notification data was similarly incomplete. In the 10 year period studied, 87 notifications of HDV infection were submitted to the Victorian Department of Health however 110 were found positive on HDV serology testing during that period; 23 cases were thus not reported (21%). The time to reporting after HDV detection was two years. 77% of cases notified were male and their median age at diagnosis was 34. Most cases were overseas-born and/or injecting drug users, however, many notifications did not provide complete information about risk factors and it is difficult to make accurate generalisations.

On a positive note, it seems clinicians are becoming more aware of the need to test for HDV in those infected with HBV, with the number of people being tested increasing dramatically over the ten year period. However, given that 17000 Victorians were diagnosed with HBV during the study period, it is clear that those with HBV are not being routinely screened for HDV co-infection and there are likely many undiagnosed cases in the community (Ref.3).

We have provided a testing algorithm to guide clinicians caring for patients with chronic HBV infections, all of whom should be investigated for HDV co-infection. We have also recommended that a cross-sectional serosurvey be conducted of patients with HBV, to assess the true incidence of HDV in Victoria.

1. Holmberg S, Ward J. Hepatitis delta: seek and ye shall find. J Infect Dis 2010; 202: 822–4.
2. Hughes S, Wedemeyer H, Harrison P. Hepatitis delta virus. Lancet 2011; 378: 73–85.
3. European Association for the Study of the Liver. EASL clinical practice guidelines: management of chronic hepatitis B virus infection. J Hepatol 2012; 57: 167–85.

Lead author contact details: bella.shadur@gmail.com

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