Annual variation rate of KL-6 for predicting acute exacerbation in patients with rheumatoid arthritis-associated interstitial lung disease

Does a window of opportunity for rheumatoid arthritis-associated interstitial lung disease exist?

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammatory synovitis, eventually leading to joint destruction. Remarkable advancements in the emergence of molecular targeted therapies and the treatment strategy based on treat-to-target have made it possible for patients to lead their daily lives without disabilities. Specifically, early diagnosis and appropriate treatment without missing a 'window of opportunity' are crucial for improving joint outcomes. On the other hand, interstitial lung disease (ILD) is an extra-articular complication of RA and has an impact on life prognosis. Importantly, it has become evident that achieving remission of arthritis is critical not only for joint outcomes but also to prevent the irreversible progression of pulmonary fibrosis in RA-ILD. Therefore, a 'window of opportunity' may exist not only for joints but also for RA-ILD. However, within RA-ILD, there are cases that progress from an NSIP pattern or airway involvement to a UIP pattern, while there are cases without progression, suggesting that their disease behavior may be diverse. Thus, accumulating evidence is necessary to accurately determine the disease behavior of RA-ILD. This review provides an overview of clinical and radiological features and treatment strategies for RA-ILD, incorporating the latest findings.

Prognostic factors affecting respiratory-related death in patients with rheumatoid arthritis complicated by interstitial lung disease: An ANSWER cohort study

The aim of this multi-centre retrospective study was to clarify the prognostic factors for respiratory-related death in patients with interstitial lung disease (ILD) complicated rheumatoid arthritis (RA). Patient background data, treatment regimen, and disease activity indicators of RA and ILD at baseline, 6 months after the diagnosis of ILD, and at the last follow-up visit were extracted. A total of 312 patients with RA-ILD (17 patients who died from respiratory-related causes and 295 survivors) were included. Patients who died from respiratory-related causes had an older median age, a higher proportion of being male, and a higher anti-cyclic citrullinated peptide antibody positivity rate than survivors (p = .0001, .038, and .016, respectively); they also had significantly higher baseline serum levels of Krebs von den Lungen-6 (KL-6) than survivors (p = .013). Patients who died from respiratory-related causes showed significantly greater changes in serum KL-6 levels between the 6-month time point and the last visit [ΔKL-6 (6 months - last)] than survivors (p = .011). Multivariate analysis showed that the ΔKL-6 (6 months - last) corrected by disease duration was a predictor of respiratory-disease-related death in patients with RA-ILD (p < .0001). Long-term increase in serum KL-6 levels is associated with respiratory-disease related death in patients with RA-ILD.

Incidence, risk factors, and prognosis of acute exacerbation of rheumatoid arthritis-associated interstitial lung disease: a systematic review and meta-analysis

INTRODUCTION

Acute exacerbation (AE) is a devastating complication of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and leads to high mortality. This study aimed to investigate the incidence, risk factors, and prognosis of acute exacerbation of rheumatoid arthritis-associated interstitial lung disease (AE-RA-ILD).

METHODS

PubMed, EMBASE, Web of Science, and Medline were searched through 8 February 2023. Two independent researchers selected eligible articles and extracted available data. The Newcastle Ottawa Scale was used to assess the methodological quality of studies used for meta-analysis. The incidence and prognosis of AE-RA-ILD were investigated. Weighted mean differences (WMDs) with corresponding 95% confidence intervals (CIs) and pooled odds ratios (ORs) with 95% CIs were calculated to explore the risk factors of AE in RA-ILD.

RESULTS

Twenty-one of 1,589 articles were eligible. A total of 385 patients with AE-RA-ILD, of whom 53.5% were male, were included. The frequency of AE in patients with RA-ILD ranged from 6.3 to 55.6%. The 1-year and 5-year AE incidences were 2.6-11.1% and 11-29.4%, respectively. The all-cause mortality rate of AE-RA-ILD was 12.6-27.9% at 30 days and 16.7-48.3% at 90 days. Age at RA diagnosis (WMD: 3.61, 95% CI: 0.22-7.01), male sex (OR: 1.60, 95% CI:1.16-2.21), smoking (OR: 1.50, 95% CI: 1.08-2.08), lower forced vital capacity predicted (FVC%; WMD: -8.63, 95% CI: -14.68 to - 2.58), and definite usual interstitial pneumonia (UIP) pattern (OR: 1.92, 95% CI: 1.15-3.22) were the risk factors of AE-RA-ILD. Moreover, the use of corticosteroids, methotrexate, and biological disease-modifying anti-rheumatic drugs, was not associated with AE-RA-ILD.

CONCLUSION

AE-RA-ILD was not rare and had a poor prognosis. Age at RA diagnosis, male sex, smoking, lower FVC%, and definite UIP pattern increased the risk of AE-RA-ILD. The use of medications, especially methotrexate and biological disease-modifying anti-rheumatic drugs, may not be related to AE-RA-ILD.

REGISTRATION

CRD42023396772.

Patient-level factors predictive of interstitial lung disease in rheumatoid arthritis: a systematic review

Objective Interstitial lung disease (ILD) is an important cause of mortality in some patients with rheumatoid arthritis (RA). Patient-level factors may predict which patients with RA are at the highest risk of developing ILD and are therefore candidates for screening for this complication of the underlying disease.Methods A systematic literature review was performed using PubMed, Embase and Scopus over a 10-year period up to July 2021. Publications reporting patient-level factors in patients with RA with and without ILD that were assessed before development of ILD (or were unchanged over time and therefore could be extrapolated to before development of ILD) were retrieved for assessment of evidence. Genetic variation in MUC5B and treatment with methotrexate were not included in the assessment of evidence because these factors have already been widely investigated for association with ILD.Results We found consistent associations of age, sex, smoking status and autoantibodies with development of ILD. For biomarkers such as Krebs von den Lungen 6, which have been shown to be diagnostic for ILD, there were no publications meeting criteria for this study.Conclusions This analysis provides an initial step in the identification of patient-level factors for potential development of a risk algorithm to identify patients with RA who may be candidates for screening for ILD. The findings represent a useful basis for future research leading to an improved understanding of the disease course and improved care for patients with RA at risk of development and progression of ILD.

Acute Exacerbations of Interstitial Lung Diseases: Focus on Biomarkers

Interstitial lung diseases (ILDs) are a large group of pulmonary disorders characterized histologically by the cardinal involvement of the pulmonary interstitium. The prototype of ILDs is idiopathic pulmonary fibrosis (IPF), an incurable disease characterized by progressive distortion and loss of normal lung architecture through unchecked collagen deposition. Acute exacerbations are dramatic events during the clinical course of ILDs, associated with high morbidity and mortality. Infections, microaspiration, and advanced lung disease might be involved in the pathogenesis of acute exacerbations. Despite clinical scores, the prediction of the onset and outcome of acute exacerbations is still inaccurate. Biomarkers are necessary to characterize acute exacerbations better. We review the evidence for alveolar epithelial cell, fibropoliferation, and immunity molecules as potential biomarkers for acute exacerbations of interstitial lung disease.

Unmet needs and perspectives in rheumatoid arthritis-associated interstitial lung disease: A critical review

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovitis as the most common clinical manifestation, and interstitial lung disease (RA-ILD) represents one of the most common and potentially severe extra-articular features. Our current understanding of the mechanisms and predictors of RA-ILD is limited despite the demonstration that an early identification of progressive fibrosing forms is crucial to provide timely treatment with antifibrotic therapies. While high resolution computed tomography is the gold standard technique for the diagnosis and follow-up of RA-ILD, it has been hypothesized that serum biomarkers (including novel and rare autoantibodies), new imaging techniques such as ultrasound of the lung, or the application of innovative radiologic algorithms may help towards predicting and detecting early forms of diseases. Further, while new treatments are becoming available for idiopathic and connective tissue disease-associated forms of lung fibrosis, the treatment of RA-ILD remains anecdotal and largely unexplored. We are convinced that a better understanding of the mechanisms connecting RA with ILD in a subgroup of patients as well as the creation of adequate diagnostic pathways will be mandatory steps for a more effective management of this clinically challenging entity.

Acute exacerbation of interstitial lung disease associated with rheumatic disease

Interstitial lung disease (ILD) is a cause of morbidity and mortality in patients with rheumatic diseases, such as connective-tissue diseases, rheumatoid arthritis and systemic vasculitis. Some patients with ILD secondary to rheumatic disease (RD-ILD) experience acute exacerbations, with sudden ILD progression and high mortality during or immediately after the exacerbation, and a very low 1-year survival rate. In the ILD subtype idiopathic pulmonary fibrosis (IPF), an acute exacerbation is defined as acute worsening or development of dyspnoea associated with new bilateral ground-glass opacities and/or consolidations at high-resolution CT, superimposed on a background pattern consistent with fibrosing ILD. However, acute exacerbation in RD-ILD (AE-RD-ILD) currently has no specific definition. The aetiology and pathogenesis of AE-RD-ILD remain unclear, but distinct triggers might include infection, mechanical stress, microaspiration and DMARD treatment. At this time, no effective evidence-based therapeutic strategies for AE-RD-ILD are available. In clinical practice, AE-RD-ILD is often empirically treated with high-dose systemic steroids and antibiotics, with or without immunosuppressive drugs. In this Review, we summarize the clinical features, diagnosis, management and prognosis of AE-RD-ILD, enabling the similarities and differences with acute exacerbation in IPF to be critically assessed.

Biomarkers for interstitial lung disease and acute-onset diffuse interstitial lung disease in rheumatoid arthritis

Interstitial lung disease (ILD) is frequently a complication of rheumatoid arthritis (RA) as an extra-articular manifestation which has a poor prognosis. Acute-onset diffuse ILD (AoDILD) occasionally occurs in RA and includes acute exacerbation of ILD, drug-induced ILD, and Pneumocystis pneumonia. AoDILD also confers a poor prognosis in RA. Previously-established biomarkers for ILD include Krebs von den lungen-6 and surfactant protein-D originally defined in patients with idiopathic pulmonary fibrosis; the sensitivity of these markers for RA-associated ILD (RA-ILD) is low. Although many studies on ILD markers have been performed in idiopathic pulmonary fibrosis, only a few validation studies in RA-ILD or AoDILD have been reported. Biomarkers for RA-ILD and AoDILD are thus still required. Recently, genomic, cytokine, antibody, and metabolomic profiles of RA-ILD or AoDILD have been investigated with the aim of improving biomarkers. In this review, we summarize current preliminary data on these potential biomarkers for RA-ILD or AoDILD. The development of biomarkers on RA-ILD has only just begun. When validated, such candidate biomarkers will provide valuable information on pathogenesis, prognosis, and drug responses in RA-ILD in future.