Clinical and healthcare burden of difficult-to-treat rheumatoid arthritis in Japan: a retrospective cohort study.

Authors

Wen S Lee, Tadashi Hosoya, Bethan Davies, Taiki Yamaguchi, Hirokazu Sasaki, Natsuka Umezawa, Tetsuya Saito, Alicia Heath, Shinsuke Yasuda

Published in

BMJ open. Volume 16. Issue 8. Pages e120136. Aug 26, 2026. Epub Aug 26, 2026.

Abstract

To quantify the clinical burden and healthcare resource use (HCRU) associated with difficult-to-treat (D2T) rheumatoid arthritis (RA) compared with non-D2T RA and evaluate clinical characteristics and factors associated with D2T RA as well as treatment patterns in Japan.
Longitudinal, retrospective observational study using electronic medical record data from 1992 to 2024 and a physician survey administered between November 2022 and November 2025.
A single academic medical centre real-world clinical practice setting in Japan.
A total of 1581 patients with RA were included.
The primary outcome measures were the comparisons of clinical burden and HCRU in the D2T RA group compared with the non-D2T RA group. D2T RA status was defined according to the European Alliance of Associations for Rheumatology definition. Clinical burden included disease activity, physical function, patient-reported outcomes, serological markers and renal function. HCRU included outpatient visits and hospitalisations evaluated over 12-month, 24-month and 36 month windows pre-index using overlap weighting and regression models. Factors associated with D2T RA status were evaluated using logistic regression. Treatment patterns were reconstructed longitudinally as lines of therapy across biologic and targeted synthetic disease-modifying antirheumatic drugs.
Among 1581 patients with RA, 102 (6.5%) met the D2T criteria. Treatment trajectories showed earlier escalation and frequent switching across biologic and targeted synthetic disease-modifying antirheumatic drugs in the D2T RA group. The D2T RA group had modestly elevated outpatient visit rates (rate ratio 1.08-1.09) and were more likely to be hospitalised (OR 4.35-6.12) than the non-D2T RA group. Factors associated with D2T RA included RA onset at age <50 (adjusted OR versus ≥50 years: 2.01, 95% CI 1.19 to 3.39), female sex (2.38, 95% CI 0.95 to 5.94) and pulmonary comorbidities (2.82, 95% CI 1.38 to 5.74).
In this real-world Japanese cohort, D2T RA was associated with higher disease burden and HCRU, particularly hospital-based care. Earlier identification and targeted management of D2T RA may help reduce the overall clinical and healthcare burden in RA.

PMID:
42648779
Bibliographic data and abstract were imported from PubMed on 27 Aug 2026.

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