This study aimed to evaluate the risk factors for end-stage renal disease (ESRD) in microscopic polyangiitis (MPA). In total, 74 patients with MPA were enrolled, and we compared the baseline clinical characteristics and disease activity between MPA patients who have progressed to ESRD and those without ESRD to select predictive factors for ESRD. Out of 74 patients, 12 patients (16.2%) had ESRD during follow-up. Serum C4 levels were significantly higher in MPA patients who have progressed to ESRD than in those without ESRD (p = 0.009). Multivariate analyses revealed that high serum creatinine levels (odds ratio (OR) 4.4, 95% confidence interval (CI) 1.25–15.5) and high serum C4 levels (OR 1.24, 95% CI 1.03–1.49) were risk factors for ESRD. Using receiver operating characteristic analysis, the cut-off value for initial serum C4 levels and serum creatinine levels were 29.6 mg/dL and 3.54 mg/dL, respectively. Patients with MPA with a greater number of risk factors (serum C4 levels > 29.6 mg/dL and serum creatinine levels > 3.54 mg/dL) had a higher ESRD progression rate. Serum C4 levels were significantly positively correlated with serum creatinine levels and kidney Birmingham vasculitis activity score (p = 0.02 and 0.04, respectively). These results suggest that serum C4 levels are useful tools for assessing renal disease activity and prognosis in MPA.

Autoimmune disorder is one of the important side effects of interferon-α therapy. Some polymyositis cases as complication of interferon-α therapy were reported, but dermatomyositis were rarely. We report a case of dermatomyositis as a complication of interferon-α therapy for hepatitis C. A 52-year-old Japanese man was treated by combination therapy with pegylated interferon-α-2b and ribavirin for hepatitis C. Three months after the initiation of therapy, he showed erythema in the posterior cervical to dorsal and anterior cervical to thoracic regions, weight loss, general malaise, muscle pain, and severe increase in levels of muscle enzymes. We made a diagnosis of dermatomyositis according to these clinical features, proximal muscle-predominant myogenic change on electromyography, and infiltration of monocytes and CD4+-dominant lymphocytes on skin biopsy, although myositis-associated antibodies were absent. He was successfully treated with intravenous immunoglobulin and tacrolimus in addition to glucocorticoid. This is a very rare case of dermatomyositis associated with interferon-α therapy. We reviewed several similar published cases and the association of dermatomyositis and type I interferon.

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.

Objectives: We evaluated the efficacy of Janus kinase inhibitors (JAKis) compared with TNF inhibitors (TNFis) in RA patients with poor-prognosis factors (PPFs), including ACPA or RF positivity, Clinical Disease Activity Index (CDAI) ≥22, CRP ≥0.6 mg/dl and HAQ-DI ≥0.5. We focused on treatment continuation, disease control and glucocorticoid (GC) reduction. Methods: We conducted a retrospective analysis of the ANSWER cohort, including 1794 RA patients treated with a TNFi (n = 1235) or JAKi (n = 559). Propensity score matching was applied to reduce bias. We categorized the patients into those with 4PPFs or <4 PPFs. Treatment persistence, CDAI changes and GC tapering over 24 months were analysed. Results: JAKi treatment demonstrated greater CDAI reduction (JAKi vs TNFi median: −23.3 vs −19.9), particularly in ACPA-positive patients. In the 4PPFs patients, JAKi treatment led to a significantly higher low disease activity achievement rate compared with TNFi (68.8% vs 60.9%) at 24 months. JAKi treatment also enabled faster GC tapering, with 72.4% discontinuation compared with 50.3% in the TNFi group at 24 months. Among the 4PPFs patients, JAKi treatment facilitated a greater (but nonsignificant) reduction in GC dosage over time. The cumulative GC discontinuation rate remained consistently higher in the JAKi group, reaching 61.3% vs 48.4% in the TNFi group at 24 months. Conclusions: JAKi treatment provided sustained disease control (especially in high-risk RA patients) and promoted GC reduction. Although TNFi remains a standard option, JAKi treatment may be preferable in patients with 4PPFs. Further research should evaluate JAKi treatment’s long-term safety and efficacy.

Objectives: We aimed to identify the impact of rheumatoid factor (RF) or anticyclic citrullinated peptide antibody (ACPA) titres on the retention of biological disease-modifying antirheumatic drugs (bDMARDs) and Janus kinase inhibitors (JAKis) in patients with rheumatoid arthritis. Methods: We retrospectively analysed 5312 courses of bDMARDs or JAKis from the ANSWER cohort. To calculate hazard ratios (HRs) for treatment discontinuation, we used multivariate Cox proportional hazards modelling, adjusted for potential confounders. Results: HRs for discontinuation due to ineffectiveness were calculated based on RF classification, revealing that anti-interleukin-6 receptor (aIL-6R) antibodies exhibited the highest retention rates regardless of RF titre. In the RF-positive group, tumour necrosis factor inhibitors (TNFis) showed lower retention rates, whereas cytotoxic T lymphocyte-associated antigen-4-Ig (CTLA4-Ig) and JAKis followed aIL-6R in the retention rates. When classified based on ACPA, aIL-6R also exhibited the highest retention rates across all ACPA groups. TNFis showed lower retention rates compared with other agents in the ACPA-positive group, whereas CTLA4-Ig showed lower retention rates in the ACPA-negative group compared with other agents. Conclusions: Considering effectiveness, aIL-6R showed the highest retention rates regardless of seropositivity. Although CTLA4-Ig and JAKis followed aIL-6R in RF or ACPA-positive cases, CTLA4-Ig showed the lowest retention rates in ACPA-negative cases.

In rheumatoid arthritis (RA), some patients experience joint pain that is disproportionate to the number of swollen joints, known as disproportionate articular pain (DP). This study aimed to clarify the prevalence and persistence of DP and to compare the outcomes across biological and targeted synthetic disease-modifying anti-rheumatic drugs (b/tsDMARDs). From the ANSWER cohort in Japan, 5489 RA patients who initiated b/tsDMARDs between January 2010 and June 2024 were screened. DP was defined as having at least seven more tender joints (TJC) than swollen joints at baseline, and 432 patients met this criterion. Persistence of DP at 3 and 6 months was evaluated. Comparative analyses were conducted across mechanisms of action (MOAs): tumour necrosis factor-α inhibitors (TNFi), cytotoxic T-lymphocyte-associated antigen-4 immunoglobulin (CTLA4-Ig), interleukin-6 inhibitors (IL-6i), and Janus kinase inhibitors (JAKi). DP was identified in 7.8% of RA patients. At 3 months, DP persisted in 40.7% (TNFi), 36.5% (CTLA4-Ig), 48.0% (IL-6i), and 54.4% (JAKi). At 6 months, corresponding rates were 43.8%, 38.7%, 49.3%, and 61.1%. Multivariate analysis showed that higher TJC and previous treatment with two or more b/tsDMARDs were associated with persistent DP, whereas higher C-reactive protein was protective. Within JAKi, baricitinib showed lower DP persistence compared with other JAKi. DP was present in approximately 8% of RA patients. Persistent DP was associated with higher TJC, greater number of previous b/tsDMARDs, and lower inflammation. No MOA was clearly superior; however, baricitinib may confer a relative benefit within the JAKi class.