Hepatitis delta testing trends in a US national cohort: An analysis of patient and provider-level predictive factors

Background: The low prevalence of HDV infection in the United States could be attributed to insufficient testing rate, which can result in an underestimation of the true burden of HDV. The primary objective of this study is to quantify the prevalence of and factors associated with HDV antibody (anti-HDV) or RNA testing, among participants with positive HBsAg in the Veterans Health Administration (VHA). Methods: We conducted a retrospective cohort study of participants who tested positive for HBsAg between January 2000 and December 2022 within the VHA. We identified those who were tested for HDV, and patient and provider-level factors associated with HDV testing. Results: Of 41,658 participants with positive HBsAg who had follow-up, 4438 (10.7%) were tested at least once for HDV, of which 135 (3.0%) were positive. Participants in the Northeast (adjusted odds ratio [aOR]: 1.30, 95% CI: 1.17–1.44, p<0.001), and receiving hepatology care (aOR: 1.38, 95% CI: 1.24–1.54, p<0.001) were more likely, while those in the Midwest (aOR: 0.69, 95% CI: 0.60–0.79, p<0.001), under the care of a primary care provider (aOR: 0.61, 95% CI: 0.50–0.74, p<0.001), Blacks (aOR: 0.85, 95% CI: 0.77–0.94, p=0.001), participants who were HCV antibody–positive (aOR: 0.89, 95% CI: 0.81–0.99, p=0.03), and participants who were HIV-positive (aOR: 0.80, 95% CI: 0.71–0.90, p<0.001) were less likely to be tested for HDV. Conclusions: HDV screening rates in the VHA remain low overall. Participants who are Black, living in the Midwest, patients who are HIV-positive, and patients who are HCV-positive are less likely to be tested for HDV. These results suggest that risk-based screening strategies are ineffective in the VHA and highlight the need for refining testing strategies to increase HDV screening rates.