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%.