Use of multiple data sources to estimate hepatitis C seroprevalence among prisoners: A retrospective cohort study.

Hepatitis C is a major cause of preventable morbidity and mortality. Prisoners are a key population for hepatitis C control programs, and with the advent of highly effective therapies, prisons are increasingly important sites for hepatitis C diagnosis and treatment. Accurate estimates of hepatitis C prevalence among prisoners are needed in order to plan and resource service provision, however many prevalence estimates are based on surveys compromised by limited and potentially biased participation. We aimed to compare estimates derived from three different data sources, and to assess whether the use of self-report as a supplementary data source may help researchers assess the risk of selection bias. We used three data sources to estimate the prevalence of hepatitis C antibodies in a large cohort of Australian prisoners-prison medical records, self-reported status during a face-to-face interview prior to release from prison, and data from a statewide notifiable conditions surveillance system. Of 1,315 participants, 33.8% had at least one indicator of hepatitis C seropositivity, however less than one third of these (9.5% of the entire cohort) were identified by all three data sources. Among participants of known status, self-report had a sensitivity of 80.1% and a positive predictive value of 97.8%. Any one data source used in isolation would have under-estimated the prevalence of hepatitis C in this cohort. Using multiple data sources in studies of hepatitis C seroprevalence among prisoners may improve case detection and help researchers assess the risk of selection bias due to non-participation in serological testing.

Trends in HIV, hepatitis B and hepatitis C prevalence among Australian prisoners - 2004, 2007, 2010.

OBJECTIVE: To report the prevalence of markers for HIV infection, hepatitis B and hepatitis C among Australian prison entrants. DESIGN: Cross-sectional survey conducted over 2-week periods in 2004, 2007 and 2010. SETTING: Reception prisons in New South Wales, Queensland, Tasmania and Western Australia. PARTICIPANTS: Individuals entering prison from the community during the survey periods. MAIN OUTCOME MEASURE: Prevalence of anti-HIV antibody (anti-HIV), hepatitis B surface antigen (HBsAg), anti-hepatitis B core antibody (anti-HBc) and anti-hepatitis C virus antibody (anti-HCV). RESULTS: The study included 1742 prison entrants: 588 (33.8%) in 2004, 536 (30.8%) in 2007 and 618 (35.5%) in 2010. The age-standardised prevalence estimates for anti-HIV, HBsAg and anti-HBc were 0.4%, 2.3% and 21.7% respectively, and remained stable over the three survey periods. The age-standardised prevalence estimate for anti-HCV was 29.0%; it decreased over time (33.3% in 2004 v 23.2% in 2010; P = 0.001), and this coincided with a decrease in prison entrants reporting injecting drug use (58.3% [343/588] in 2004 v 45.3% [280/618] in 2010; P < 0.001). Among injecting drug users, the prevalence of anti-HCV was 57.2% and did not change significantly over time. Of those who were anti-HCV positive, 33.7% (140/415) were unaware of their infection status, and 74.3% (185/249) of those who tested positive for anti-HBc reported that they had never had hepatitis B. CONCLUSIONS: HIV prevalence is low in the Australian prisoner population but transmission remains a risk. Despite a decrease in the proportion of prison entrants reporting injecting drug use, prevalence of hepatitis B and hepatitis C has remained high. Treatment and prevention initiatives should be prioritised for this population.