# Suboptimal Linkage to Care of Delta-Infected Patients in an Area with Increasing Migration-Driven Prevalence of Hepatitis D in Recent Years

## TL;DR

This study shows that many hepatitis D patients in a Spanish region are not receiving proper care, especially young migrant men, and suggests new strategies to improve care access.

## Contribution

The paper introduces a structured HDV registry and highlights barriers to care in a region with rising migration-driven HDV prevalence.

## Key findings

- Only one third of anti-HDV positive patients without adequate care could be successfully linked to care.
- 45.2% of patients had been lost to follow-up for several years.
- Young migrant men were particularly difficult to link to care.

## Abstract

Background and Aims: Changes in hepatitis delta virus (HDV) epidemiology have been highlighted recently in the context of increasing worldwide migrations. The lack of comprehensive real-world data on HDV in the Valencia region highlights the need for a structured registry to accurately estimate disease prevalence and burden and to generate robust real-world evidence on clinical outcomes and therapeutic effectiveness. We aimed to better understand the barriers for successful HDV patient care in our region by establishing a registry as well as linking previously under-recognized or lost to follow-up (FU)cases to care. Methods: After a search of all possible HDV cases in a Spanish region, attempts were made (through letters and phone calls) to relink to care those lost to FU. Two approaches were undertaken: (i) search of the Microbiology Labs Database, and (ii) clinical chart review from adult patients attending the Hepatology or Infectious Disease (ID) Units outpatient clinics of the three participant hospitals between January 2011 and June 2021. Results: Only one third of anti-HDV positive patients without adequate clinical management could be successfully linked or re-linked to care, highlighting a substantial gap in follow-up. Among 243 HDV cases detected (7.5% of HBsAg-positive patients), 111 belonged to the hospitals’ health department, and after excluding deceased or transplanted individuals, the final study cohort consisted of 84 patients. Of these, 27.4% were adequately followed in Hepatology or Infectious Disease Clinics, 11.9% had been inadequately followed recently, 45.2% had been lost to follow-up for several years, and 15.5% had never been evaluated in outpatient clinics. Overall, only a third of the patients without adequate clinical management could be successfully linked/relinked to care. Conclusions: In our setting, only a minority of anti-HDV positive patients are adequately managed in specialized outpatient clinics, with unsuccessful attempts to link many patients to care, particularly among young migrant men. These findings underscore the need for alternative strategies, such as decentralized testing, reflex testing, and the involvement of patient navigators or social workers, to strengthen linkage to care and improve retention.