Enhancing Hepatitis Delta Diagnosis in Southern Spain: Efficacy and
Economic Evaluation of Double Reflex Testing
Abstract
Background & Aim: This study aims to evaluate the prevalence
of undiagnosed hepatitis delta in southern Spain (Andalusia) and assess
the effectiveness and cost-efficiency of implementing reflex testing for
hepatitis D detection in HBsAg-positive patients. Patient &
Methods: A multicenter ambispective study was conducted in 17 hospitals
in Andalusia. The retrospective phase analyzed diagnostic processes for
hepatitis delta from January 2018 to June 2022, focusing on
HBsAg-positive patients. The prospective phase, from October 2022 to
March 2023, implemented reflex testing, performing anti-HDV serology on
all HBsAg-positive patients without prior testing. HDV RNA testing was
conducted on those who tested positive for anti-HDV. Results:
In the retrospective phase, out of 18,583 HBsAg-positive patients,
anti-HDV tests were performed on 3,436 (18%), identifying 205 (6%)
positive cases. HDV RNA was tested in 158 (77%) anti-HDV-positive
patients, with 69 (44%) testing positive. In the prospective phase, out
of 2,384 HBsAg-positive patients without prior anti-HDV testing, 2,293
(96%) were tested, identifying 109 (4.7%) positive cases. HDV RNA was
analyzed in 97 (89%) anti-HDV-positive patients, with 30 (31%) testing
positive. Reflex testing increased anti-HDV detection by 77%, resulting
in a fourfold increase in detecting anti-HDV-positive patients and a
threefold increase in detecting HDV RNA-positive patients, reducing
undiagnosed HDV RNA-positive cases to 4% compared to 45% with clinical
practice. Cost analysis indicated a saving of €265,954 with reflex
testing. Discussion: Reflex testing significantly improves HDV
detection and reduces healthcare costs. It simplifies the diagnostic
process, increasing the detection rate of hidden chronic hepatitis delta
patients and proving to be an efficient strategy for managing chronic
hepatitis B patients.