Background: Rheumatoid arthritis-associated interstitial lung disease (RA-ILD) is a major complication of rheumatoid arthritis (RA), but effective treatment remains an unmet need in its management. Our aim was to evaluate the therapeutic efficacy of abatacept for RA-ILD. Methods: This observational retrospective study included patients with RA-ILD treated with abatacept between 2012 and 2021. Indices of RA disease activity and interstitial lung disease (Disease Activity Score in 28 joints using C-reactive Protein [DAS28-CRP], Simplified Disease Activity Index [SDAI], Clinical Disease Activity Index [CDAI], serum Krebs von den Lungen-6 levels, % forced vital capacity [%FVC], and semi-quantified chest high-resolution computed tomography scores) were evaluated before and 1 year after the start of abatacept administration. Results: Overall, 38 patients were included. DAS28-CRP, SDAI, and CDAI were significantly improved (all with p < 0.0001). Total ground-glass opacity scores were decreased in both patients with usual interstitial pneumonia (UIP)-like patterns and with non-UIP-like patterns (p = 0.008 and <0.002, respectively). Total fibrosis scores were also decreased in the UIP-like pattern group (p < 0.042). The %FVC remained stable. Conclusions: Abatacept significantly improves RA disease activity and reduces pulmonary inflammation in patients with RA-ILD.

This multicenter retrospective study aimed to clarify the prognostic factors for mortality and changes in treatment modalities and disease activities after the onset of Pneumocystis jirovecii pneumonia (PCP) in patients with rheumatoid arthritis (RA). Data regarding the clinical background, treatment modalities, and disease activity indicators of RA at the onset of PCP (baseline), and 6 months and 12 months after treatment were extracted. Of the 37 patients with RA-PCP (median age, 69 years; 73% female), chemical prophylaxis was administered to 8.1%. Six patients died during PCP treatment. The serum C-reactive protein (CRP) levels and the prednisolone (PDN) dose at baseline in the PCP death group were significantly higher than those in the survivor group. Multivariate analysis using a Cox regression model showed that PDN dose at baseline was a predictor of death from PCP in patients with RA. During the 12 months from baseline, the RA disease activity significantly decreased. A high dose of corticosteroids for RA may result in a poor prognosis when PCP is complicated. In the future, preventive administration techniques must be established for patients with RA who need PCP prevention.

Background/Objectives: In rheumatoid arthritis-associated interstitial lung disease (RA-ILD), factors associated with moderate-to-high disease activity (MDA/HDA) during follow-up are not well defined. We examined baseline factors associated with MDA/HDA at 6 months. Methods: We analyzed 278 patients with RA-ILD from the multicentre ANSWER cohort. At 6 months, patients were classified by the 28-joint Disease Activity Score using erythrocyte sedimentation rate (DAS28-ESR) as remission/low disease activity (LDA) or MDA/HDA. Logistic regression used age and baseline DAS28-ESR as continuous variables (n = 178 with complete baseline DAS28-ESR); discrimination, calibration and optimism (1000 bootstrap resamples) were assessed. A sensitivity analysis used the ESR-free Clinical Disease Activity Index (CDAI) as the outcome. Results: In all, 148 patients achieved remission/LDA and 130 had MDA/HDA. Baseline DAS28-ESR was independently associated with MDA/HDA (odds ratio 2.01 per point, 95% CI 1.57–2.57), as was age (1.05 per year, 1.01–1.08). The area under the curve was 0.768 for DAS28-ESR alone and 0.776 with age added; internal validation of the two-variable model showed little estimated optimism (corrected area 0.772, calibration slope 0.984, 95% CI 0.693–1.396). With the CDAI-based outcome, the association with age was not reproduced (odds ratio 1.00, 0.97–1.04). Conclusions: Baseline disease activity is strongly associated with MDA/HDA at 6 months in RA-ILD. The incremental value of age was small, and the association with age was not reproduced when the outcome was defined by the CDAI. The age finding should therefore be regarded as secondary and dependent on the disease activity measure used. External and prospective validation is required before these findings are applied clinically.