Revisiting Ferritin‐
IgG
Score to Predict Complete Biochemical Response in Autoimmune Hepatitis
Álvaro Díaz‐González, Bastian Engel, Manuel Hernández‐Guerra, Indhira Pérez‐Medrano, Beatriz Mateos, Rosa M. Morillas, Elena Gómez, Judith Gómez, Diana Horta, Isabel Conde, María Del Barrio, Ignasi Olivas, Ismael El Hajra, Mar Riveiro‐Barciela, Ana Barreira‐Díaz, Carmen López, Carmen Álvarez‐Navascúes, Manuel Rodríguez Perálvarez, Elmar Jaeckel, Richard Taubert, María‐Carlota Londoño ABSTRACT
Background
Predictive tools in autoimmune hepatitis (AIH) are scarce. A study proposed low ferritin and high IgG as prognostic markers for complete biochemical response (CBR).
Aims
We aimed to externally validate the prognostic role of ferritin‐IgG score and its individual components in an independent multicentre AIH cohort.
Methods
This multicentre study included 487 patients from the Hannover cohort ( n = 166) and the Spanish ColHai registry ( n = 321). Patients with ferritin < 2.09×ULN received 1 point and those with IgG > 1.89×ULN received 1 point, yielding a score of 0–2. Because baseline characteristics differed between cohorts, the score was additionally evaluated after inverse probability of treatment weighting (IPTW) propensity score.
Results
At baseline, Hannover patients were younger ( p = 0.005) and had higher transaminases, bilirubin ( p < 0.001), ferritin ( p = 0.006) and IgG ( p = 0.006). Overall, 79.7% achieved CBR; CBR rates were higher in ColHai at 6 (50.2% vs. 34.6%, p = 0.001) and 12 months (67.6% vs. 51.9%, p = 0.001). The score was associated with response in the Hannover cohort but showed no predictive capacity in ColHai (C‐statistic 0.51 [95% CI 0.45–0.56] at 6 months; 0.51 [0.45–0.57] at 12 months; 0.54 [0.47–0.61] at any time during the follow‐up). After IPTW, the score was not associated with CBR in the ColHai cohort (HR 0.86, 95% CI 0.67–1.10), whereas IgG retained its predictive value, with baseline levels < 1.89×ULN associated with a higher probability of achieving CBR.
Conclusions
The ferritin‐IgG score failed external validation in an independent multicentre cohort. Ferritin showed no prognostic value, whereas the predefined IgG threshold retained its ability to predict treatment response.