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An International Multispecialty Validation Study of the IgG4‐Related Disease Responder Index
Author(s) -
Wallace Zachary S.,
Khosroshahi Arezou,
Carruthers Mollie D.,
Perugino Cory A.,
Choi Hyon,
Campochiaro Corrado,
Culver Emma L.,
Cortazar Frank,
Dellatorre Emanuel,
Ebbo Mikael,
Fernandes Ana,
Frulloni Luca,
Hart Phil A.,
Karadag Omer,
Kawa Shigeyuki,
Kawano Mitsuhiro,
Kim MyungHwan,
Lanzillotta Marco,
Matsui Shoko,
Okazaki Kazuichi,
Ryu Jay H.,
Saeki Takako,
Schleinitz Nicolas,
Tanasa Paula,
Umehara Hisanori,
Webster George,
Zhang Wen,
Stone John H.
Publication year - 2018
Publication title -
arthritis care and research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.032
H-Index - 163
eISSN - 2151-4658
pISSN - 2151-464X
DOI - 10.1002/acr.23543
Subject(s) - medicine , intra rater reliability , construct validity , physical therapy , confidence interval , inter rater reliability , igg4 related disease , disease , psychometrics , rating scale , statistics , clinical psychology , mathematics
Objective IgG4‐related disease (IgG4‐ RD ) can cause fibroinflammatory lesions in nearly any organ, leading to organ dysfunction and failure. The IgG4‐ RD Responder Index ( RI ) was developed to help investigators assess the efficacy of treatment in a structured manner. The aim of this study was to validate the RI in a multinational investigation. Methods The RI guides investigators through assessments of disease activity and damage in 25 domains, incorporating higher weights for disease manifestations that require urgent treatment or that worsen despite treatment. After a training exercise, investigators reviewed 12 written IgG4‐ RD vignettes based on real patients. Investigators calculated both an RI score as well as a physician's global assessment (Ph GA ) score for each vignette. In a longitudinal assessment, 3 investigators used the RI in 15 patients with newly active disease who were followed up over serial visits after treatment. We assessed interrater and intrarater reliability, precision, validity, and responsiveness. Results The 26 physician investigators included representatives from 6 specialties and 9 countries. The interrater and intrarater reliability of the RI was strong (0.89 and 0.69, respectively). Correlations (construct validity) between the RI and Ph GA were high (Spearman's r = 0.9, P < 0.0001). The RI was sensitive to change (discriminant validity). Following treatment, there was significant improvement in the RI score (mean change 10.5 [95% confidence interval (95% CI) 5.4–12], P < 0.001), which correlated with the change in the Ph GA . Urgent disease and damage were captured effectively. Discussion In this international, multispecialty study, we observed that the RI is a valid and reliable disease activity assessment tool that can be used to measure response to therapy.