Interstitial lung disease in ANCA-associated vasculitis: associated factors, radiographic features and mortality

Interstitial lung disease in patients with antineutrophil cytoplasmic antibody-associated vasculitis: chest CT patterns and correlation with survival

BACKGROUND

Interstitial lung disease (ILD) is common in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), with usual interstitial pneumonia (UIP) being the most frequent pattern. The impact of different ILD patterns on clinical outcomes remains unclear.

METHODS

Retrospective cohort study included patients with AAV (MPA and GPA) and ILD confirmed by chest CT scans between 1997 and 2021. ILD patterns were classified according to 2018 Fleischner Society criteria.

RESULTS

Of 1862 patients in the Mayo AAV Cohort, 143 (7.7 %) had ILD on chest CT. The median age at the time of ILD diagnosis (occurring before AAV diagnosis in 26.6 %) was 69 years (IQR 61-75); 60 % were male, and 75 % were MPO-positive. On chest CT, "typical UIP" pattern was identified in 44 patients (30.8 %), whereas 13 (9.1 %) manifested "probable UIP" pattern, 37 (25.9 %) "indeterminate for UIP" pattern, and 49 (34.3 %) "non-UIP" pattern. Among MPO-ANCA patients, typical UIP pattern was most common (37.4 %), while non-UIP pattern was most common (58.3 %) among PR3-ANCA patients. Patients with typical UIP pattern, when compared to those with non-UIP pattern, were more commonly male (70.5 %), MPO-ANCA (90.0 %), diagnosed before the onset of AAV (40.9 %), and had reduced diffusion capacity on pulmonary function tests. The presence of typical UIP was related with higher survival at 12 months and 10 years in MPO-ANCA patients when compared to other ILD patterns (IRR 8.201 and IRR 2.179).

CONCLUSIONS

The typical UIP pattern in AAV-ILD is associated with better survival, particularly in MPO-ANCA patients, suggesting distinct mechanisms for ILD development in MPO vs. PR3-AAV.

Risk factors for poor prognosis in ANCA-associated vasculitis with interstitial lung disease: a systematic review and meta-analysis

OBJECTIVE

Antineutrophil cytoplasm antibody-associated vasculitis (AAV) with interstitial lung disease (AAV-ILD) is the main manifestation of AAV involving the lung, further increasing the risk of poor prognosis in patients with AAV. This study aimed to investigate the risk factors associated with mortality in patients with AAV-ILD.

METHODS

In Web of Science, PubMed, Embase and Scopus databases, a comprehensive search was performed for English studies on AAV and ILD published from inception date until May 17, 2024. Hazard ratios (HR) and 95% confidence intervals (CI) of mortality-related risk factors in AAV-ILD were collected, and subgroup analyses were carried out based on different candidate risk factors. Cochran's Q statistic and inconsistency value were utilized to assess the heterogeneity of included studies. Sensitivity analysis was executed using one-by-one elimination method, and publication bias was evaluated with Egger's test and the trim-and-fill method.

RESULTS

A total of 654 patients with AAV-ILD in eight studies were included for the pooled analysis of mortality risk factors. The results showed that age (HR = 1.06, 95%CI: 1.04, 1.08), ever smoker (HR = 1.61, 95%CI: 1.13, 2.29), usual interstitial pneumonia pattern (HR = 2.07, 95%CI: 1.43, 3.00), acute exacerbation (HR = 2.73, 95%CI: 1.70, 4.40) and microscopic polyangiitis (HR = 4.03, 95%CI: 1.70, 9.55) were associated with an increased risk of AAV-ILD mortality. Conversely, percent predicted forced vital capacity (HR = 0.97, 95%CI: 0.96, 0.99) and immunosuppressant for induction (HR = 0.40, 95%CI: 0.28, 0.58) were associated with a reduced risk of AAV-ILD mortality. Male (HR = 1.27, 95%CI: 0.90, 1.80), nervous system involvement (HR = 0.99, 95%CI: 0.65, 1.52), renal involvement (HR = 1.24, 95%CI: 0.97, 1.95) and five factor score ≥ 1 (HR = 1.00, 95%CI: 0.67, 1.48) showed no significant correlation with mortality risk in patients with AAV-ILD. Heterogeneity test indicated no significant heterogeneity among the pooled studies. The results of sensitivity analysis, Egger's test and the trim-and-fill method revealed that the pooled findings were stable and reliable.

CONCLUSION

The pooled analyses demonstrated that age, ever smoker, usual interstitial pneumonia pattern, acute exacerbation and microscopic polyangiitis were risk factors for mortality in patients with AAV-ILD, while percent predicted forced vital capacity and immunosuppressant therapy for induction serve as protective factors against mortality. A systematic understanding of the risk factors for AAV-ILD may provide clues for developing effective interventions and managements to improve poor prognosis in patients. Key Points • Increase of age, ever smoker, usual interstitial pneumonia pattern, acute exacerbation and microscopic polyangiitis were risk factors for poor prognosis in patients with AAV-ILD. • High level of percent predicted forced vital capacity and immunosuppressant therapy for induction serve as protective factors against poor prognosis. • Male, nervous system involvement, renal involvement and five factor score ≥ 1 showed no significant correlation with poor prognosis in patients with AAV-ILD.

Clinical Profiles, Survival, and Lung Function Outcomes in ANCA-Associated Interstitial Lung Disease: An Observational Study

Background/Objectives: Anti-neutrophil cytoplasmic antibodies (ANCAs) have been found in interstitial lung disease (ILD) in recent years, although its impact on ILD prognosis is less known. To date, ANCAs are not included in the interstitial pneumonia with autoimmune features (IPAF) definition criteria. Therefore, ANCA-ILD, in the absence of known ANCA-associated vasculitis (AAV), could be underdiagnosed. Our aim was to analyze the clinical profile and prognosis of ANCA-ILD patients. Methods: Patients diagnosed with ILD and positive ANCA were enrolled in a retrospective, monocentric cohort study. Lung function outcomes and mortality were assessed according to clinical, serological, radiological, and treatment characteristics. Survival was analyzed using Kaplan-Meier curves and Cox regression models. Results: A total of 23 patients were included, mostly women, with a median time from ILD diagnosis of 36 (24-68) months and a predominant anti-MPO pattern (56.5%). Nearly half of the patients had AAV, mostly microscopic polyangiitis (MPA). The presence of AAV was significantly associated with anti-MPO antibodies and an NSIP radiographic pattern. Overall, the fibrotic pattern (either UIP or fibrotic NSIP) was the most common (73.9%), mainly UIP (51.2%). However, it appeared less frequently in the AAV-ILD group. During follow-up, lung function impairment or radiological progression was observed in 65.2% of patients. Cumulative mortality incidence was high (43.4%), largely due to ILD itself (80%). A UIP pattern was associated with a higher and earlier mortality (HR 34.4 [1.36-132]), while the use of immunosuppressants showed a trend towards lower ILD-related death. Conclusions: In our cohort, ANCA-ILD patients mostly presented with fibrotic patterns, with AAV in almost half of the cases and a high and early mortality rate, which suggests the need to assess ANCA in all ILD patients.

Rationale for phosphodiesterase-4 inhibition as a treatment strategy for interstitial lung diseases associated with rheumatic diseases

Interstitial lung disease (ILD) associated with rheumatoid arthritis or with connective tissue diseases such as systemic sclerosis can be collectively named systemic autoimmune rheumatic disease-associated ILDs (SARD-ILDs) or rheumatic musculoskeletal disorder-associated ILDs. SARD-ILDs result in substantial morbidity and mortality, and there is a high medical need for effective therapies that target both fibrotic and inflammatory pathways in SARD-ILD. Phosphodiesterase 4 (PDE4) hydrolyses cyclic AMP, which regulates multiple pathways involved in inflammatory processes. PDE4 is overexpressed in peripheral blood monocytes from patients with inflammatory diseases. However, clinical data on pan-PDE4 inhibition in fibrotic conditions are lacking. The PDE4B subtype is highly expressed in the brain, lungs, heart, skeletal muscle and immune cells. As such, inhibition of PDE4B may be a novel approach for fibrosing ILDs such as idiopathic pulmonary fibrosis (IPF) and SARD-ILD. Preclinical data for PDE4B inhibition have provided initial evidence of both anti-inflammatory and antifibrotic activity, with reduced potential for gastrointestinal toxicity compared with pan-PDE4 inhibitors. In a proof-of-concept phase II trial in patients with IPF, nerandomilast (BI 1015550), the only PDE4B inhibitor currently in clinical development, prevented a decline in lung function over 12 weeks compared with placebo. The potential clinical benefit of PDE4B inhibition is now being investigated in the phase III setting, with two trials evaluating nerandomilast in patients with IPF (FIBRONEER-IPF) or with progressive pulmonary fibrosis other than IPF (FIBRONEER-ILD). Here, we review the preclinical and clinical data that provide rationale for PDE4B inhibition as a treatment strategy in patients with SARD-ILD.

Clinical features, radiological findings and prognosis of microscopic polyangiitis with interstitial lung disease: a retrospective matched control study

BACKGROUND

The association between interstitial lung disease (ILD) and microscopic polyangiitis (MPA) has received increasing attention in recent years. However, there are still no studies comparing clinical characteristics and prognoses between MPA-ILD patients and patients with ANCA-negative ILDs. Therefore, the purpose of this study was to analyse a group of patients presenting MPA-ILD matched with patients exhibiting ANCA-negative ILDs to identify differences in their clinical characteristics and survival.

METHODS

This study retrospectively reviewed the data of 60 patients with MPA-ILD and 60 patients with ANCA-negative ILDs who were matched for age, sex, and patterns on chest high-resolution CT (HRCT) images. The baseline clinical information, laboratory parameters and chest CT data were collected and analysed at each patient's initial diagnosis.

RESULTS

Sixty of the 682 (8.8%) ILD patients were diagnosed with MPA-ILD. MPA-ILD patients tended to be older and have higher CRP and ESR levels. ILD antedated MPA in 61.7% (37/60) of the patients, and MPA occurred on average (45.1 ± 33.4) months after the ILD diagnosis. Compared with matched ANCA-negative ILD patients, MPA-ILD patients had higher CRP and serum creatinine levels and lower haemoglobin levels. UIP (63.3%) was the most common chest HRCT pattern, and the proportion of patients with oddly shaped cysts (P = 0.04) was significantly greater in the MPA-ILD group than in the matched ANCA-negative ILD group. The number of MPA-ILD patients was significantly shorter than that of ANCA-negative ILD patients (P = 0.005). Survival analysis revealed that acute exacerbation (AE) of ILD (HR 2.40, 95% CI 1.03-5.59, P = 0.043) and diffuse alveolar haemorrhage (HR 3.42, 95% CI 1.09-10.73, P = 0.036) were independently associated with shorter survival and that receiving glucocorticoids combined with immunosuppressants (HR 0.11, 95% CI 0.03-0.37, P < 0.001) was independently associated with prolonged survival in MPA-ILD patients.

CONCLUSIONS

The proportion of MPA-ILD patients with total ILD is not low, and ANCA testing of ILD patients is necessary. Oddly shaped cysts with a UIP pattern may be a characteristic chest imaging manifestation of MPA-ILD. The prognosis of MPA-ILD is poor, especially for patients who are older, have DAH, and have experienced AEs.

Prognostic analysis of Pneumocystis jirovecii pneumonia in patients with systemic vasculitides: a retrospective cohort study

OBJECTIVES

Pneumocystis jirovecii pneumonia (PJP) is a serious complication of autoimmune and inflammatory diseases. This study aimed to describe the characteristics of PJP in patients with various systemic vasculitides and explore potential prognostic factors.

METHOD

Data on 62 enrolled PJP patients with systemic vasculitis were analyzed. Patients were stratified based on the outcomes. Prognostic factors were investigated using Cox-regression models. Characteristics of patients with and without interstitial lung disease (ILD) were compared.

RESULTS

Among 62 vasculitis-PJP patients, 48 had anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV), with microscopic polyangiitis (MPA) being the most common subtype (28 patients). MPA (HR 4.33, p = 0.001), concomitant aspergillosis (HR 2.68, p = 0.019), and higher D-dimer at PJP diagnosis (HR 1.07, p = 0.004) were independent adverse prognostic factors for overall survival. Stable disease activity of vasculitis was an independent favorable prognostic factor (HR 0.28, p = 0.027). Patients with MPA were older than non-MPA patients (median age: 69 vs. 58 years, p = 0.001); both ILD and fibrotic ILD were more prevalent in MPA patients (ILD: 78.6% vs. 35.3%, p = 0.001; fibrotic ILD: 57.1% vs. 11.8%, p < 0.001). At the diagnosis of PJP, patients with preexisting ILD had higher counts of white cells, lymphocytes, and neutrophils, as well as higher levels of immunoglobulin (Ig) G and IgA, than patients without preexisting ILD.

CONCLUSIONS

MPA was associated with a higher risk of death in patients with vasculitis-PJP, possibly due to a higher prevalence of ILD. In clinical practice, we should pay more attention to the prophylaxis and management of PJP in patients with systemic vasculitis-associated ILD and/or MPA. Key Points • Data from this study showed that MPA was the most common subtype of vasculitis among vasculitis-PJP patients. • Compared with non-MPA patients in this study, patients with MPA were older, had more ILD and fibrotic ILD, and had a poorer prognosis. • In clinical practice, we should pay more attention to the prophylaxis and management of PJP in patients with systemic vasculitis-associated ILD and/or MPA.

Takayasu arteritis and interstitial lung disease: a case report and literature review

Introduction and importance

Although pulmonary artery involvement is well recognized, the incidence of interstitial lung disease (ILD) with Takayasu arteritis is very rare. The pathophysiology of ILD in Takayasu is still incompletely understood, in contrast to several studies establishing the relationship between ANCA-associated vasculitis and ILD. The management of this patient involved a multidisciplinary approach with long-term follow-up.

Case presentation

The authors present a case of HRCT-proven interstitial lung disease in a patient with Takayasu arteritis and heart failure. The patient was on long-term corticosteroids on and off for several years and recently developed progressive dyspnea with a dry cough. After reviewing her history and physical examination, pulmonary function tests (PFTs) and high-resolution computed tomography (HRCT) were performed, and interstitial lung disease was diagnosed. The patient was managed by a team of pulmonologists, rheumatologists, and cardiologists and gradually improved after adjustment of medications, including corticosteroids and mycofenolate, and via long-term oxygen therapy.

Clinical discussion

Takayasu arteritis is a rare form of systemic vasculitis that can involve the pulmonary vasculature, such vasculitis with associated parenchymal involvement is rare. ILDs have been demonstrated with ANCA-associated vasculitis; however, whether the pathophysiology applies to Takayasu is unknown. Since Takayasu can be debilitating to the patient, the association of ILDs can have further prognostic implications. Given that no established guidelines exist to address this association, management is based on clinical expertise.

Conclusion

The authors report a case of Takayasu arteritis and associated ILD and its pharmacological management. Takayasu arteritis is a very uncommon type of vasculitis, and pulmonary parenchymal involvement further contributes to this case's rarity. As the management of Takayasu arteritis alone is cumbersome, the addition of another significant comorbidity, such as ILD, can pose several threats to the patient. Given the rarity of this association, no established guidelines exist, making clinical expertise crucial for managing such patients. Further research is needed to explore the underlying mechanisms and develop evidence-based treatment strategies for this rare combination.

Clinical Significance of Overlap Syndrome of Histologically Confirmed Lupus Nephritis with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

Objectives: We applied the 2022 American College of Rheumatology/ European Alliance of Association for Rheumatology (ACR/EULAR) criteria for antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) to patients histologically diagnosed with lupus nephritis (LN) to investigate the overall rate of and initial contributing factors to the reclassification of overlap syndrome of LN with AAV (OS-LN-AAV). Methods: We retrospectively reviewed the medical records of 1292 patients with systemic lupus erythematosus (SLE) and included 164 patients with LN in this study. Patient demographics, SLE manifestations, LN classes, and laboratory data, including ANCA levels, were recorded. All-cause mortality and end-stage kidney disease (ESKD) were evaluated as poor outcomes. Results: The median age of the 164 patients was 37.0 years, and 12.2% were men. The overall reclassification rate was 37.8%, of which 34.1% and 3.7% of the patients were reclassified as having OS-LN-microscopic polyangiitis and OS-LN-granulomatosis with polyangiitis (GPA), respectively, but none as having eosinophilic GPA. ANCA positivity and AAV-suggesting lung lesions were major contributors to OS-LN-AAV reclassification. When patients were compared based on OS-LN AAV reclassification, ANCA positivity and myeloperoxidase-ANCA (or P-ANCA) positivity favoured for OS-LN-AAV reclassification, whereas oral ulcers did not. However, OS-LN-AAV reclassification did not affect all-cause mortality or ESKD. Conclusions: This is the first study demonstrating a 37.8% reclassification rate in patients histologically diagnosed with LN using the 2022 ACR/EULAR criteria for AAV. Furthermore, it was also the first to reveal ANCA positivity and AAV-suggesting lung lesions as major contributors to OS-LN-AAV reclassification.

Granulomatosis with polyangiitis: clinical characteristics and updates in diagnosis

Granulomatosis with polyangiitis (GPA) is a rare systemic disease characterized by granulomatous inflammation of the respiratory tract and necrotizing vasculitis of small and medium vessels often associated with the production of anti-neutrophil cytoplasmic antibodies (ANCA) directed mainly against leukocyte proteinase 3 (PR3). Usually, it involves upper airways, lungs, and kidneys, however any organ may be affected. The diagnosis is based on clinical, radiological, and serological findings. Biopsies, although strongly recommended, are not always feasible and often provides non-specific features. ANCA plays a crucial role in the diagnosis of GPA; nevertheless, ANCA detection is not a substitute for biopsy, which plays an important role in suspected cases, particularly when histological confirmation cannot be obtained. Significant advances have been made in classification criteria and phenotyping of the disease, particularly in determining the nuances between PR3-ANCA and myeloperoxidase (MPO)-ANCA vasculitis. This has led to better characterization of patients and the development of targeted treatment in the future. In addition, better identification of cytokine and immunological profiles may result in immuno-phenotyping becoming a new approach to identify patients with ANCA-associated vasculitis (AAV). Due to the chronic relapsing-remitting nature, strict follow-up of GPA is necessary to provide appropriate management. The search for the accurate marker of disease activity and to predict relapse is still ongoing and no predictor has been found to reliably guide therapeutic decision-making.

Antineutrophil cytoplasmic antibody is an independent risk factor in rheumatoid arthritis-associated interstitial lung disease

OBJECTIVES

This study aimed to investigate the clinical relevance of antineutrophil cytoplasmic antibody (ANCA) in patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD).

METHODS

Detailed clinical records of rheumatoid arthritis (RA) patients who underwent ANCA screening tests were collected. ANCA measurements were determined by indirect immunofluorescence assay (IIF) and enzyme-linked immunosorbent assay (ELISA). Clinical characteristics were compared between ANCA-positive and ANCA-negative groups, and multivariable logistic models were used to evaluate the independent association of ANCA with ILD in RA patients.

RESULTS

The prevalence of ANCA by IIF was significantly higher in RA-ILD patients compared to those with RA without ILD (31.7 % vs. 19.5 %, p < 0.001). RA-ILD patients positive for ANCA exhibited elevated levels of inflammatory markers and greater disease activity, and showed more severe impairment of lung function compared to ANCA-negative RA-ILD patients. Multivariable logistic regression analysis revealed an independent association of ANCA, especially pANCA, with RA-ILD. ANCA specificities for BPI, elastase, and cathepsin-G were found in 15.6 % of RA-ILD patients; the specificities for most others remain unknown.

CONCLUSIONS

The findings suggest a potential role for ANCA/pANCA in stratifying the risk of RA and provide supplementary information to the existing clinically available assays. This additional information may be valuable in identifying RA patients who require further investigations for RA-ILD, such as high-resolution computed tomography (HRCT). These results emphasize the potential clinical relevance of ANCA in the context of RA-ILD.

Prediction model for respiratory-related mortality in microscopic polyangiitis with interstitial lung disease: multicentre REVEAL cohort study

OBJECTIVE

This study aimed to establish prediction models for respiratory-related mortality in microscopic polyangiitis (MPA) complicated by interstitial lung disease (ILD) using clinical characteristics.

METHODS

We enrolled patients with MPA with ILD between May 2005 and June 2021 in a multicentre cohort of Japanese patients with MPA (REVEAL cohort). We evaluated the demographic, clinical, laboratory, radiological findings, treatments and the presence of honeycombing 1 cm above the diaphragm using chest high-resolution CT (HRCT) on admission. We explored the risk factors predictive of respiratory-related mortality.

RESULTS

Of 115 patients, 26 cases died of respiratory-related diseases during a median follow-up of 3.8 years. Eighteen patients (69%) died due to respiratory infection, three (12%) had diffuse alveolar haemorrhage, and five (19%) had exacerbation of ILD. In univariate analysis, older age, lower percent forced vital capacity (%FVC), lower percent diffusing capacity of carbon monoxide (%DLCO), and the presence of honeycombing in the right lower lobe were identified as risk factors. Additionally, in multivariate analysis adjusted for age and treatment, %FVC, %DLCO and the presence of honeycombing in the right lower lobe were independently associated with respiratory-related mortality. We created prediction models based on the values of %FVC, %DLCO and presence of honeycombing on chest HRCT (termed "MPF model"). The 5-year respiratory-related death-free rate was significantly different between patients with MPA with ILD stratified by the number of risk factors based on the MPF model.

CONCLUSIONS

Our study indicates that the MPF model may help predict respiratory-related death in patients with MPA with ILD.

Development of a novel predictive model for interstitial lung disease in ANCA-associated vasculitis prognostications within the Chinese population

Antineutrophil cytoplasmic antibody vasculitis-associated interstitial lung disease (AAV-ILD) is a potentially life-threatening disease. However, very little research has been done on the condition's mortality risk. Hence, our objective is to find out the factors influencing the prognosis of AAV-ILD and employ these findings to create a nomogram model. Patients with AAV-ILD who received treatment at the First Affiliated Hospital of Zhengzhou University during the period from March 1, 2011, to April 1, 2022 were selected for this research. The development of nomogram entailed a synergistic integration of univariate, Lasso, and multivariate Cox regression analyses. Internal validation ensued through bootstrap techniques involving 1000 re-sampling iterations. Discrimination and calibration were assessed utilizing Harrell's C-index, receiver operating characteristic (ROC) curve, and calibration curve. Model performance was evaluated through integrated discrimination improvement (IDI), net reclassification improvement (NRI), and likelihood ratio test. The net benefit of the model was evaluated using decision curve analysis (DCA). A cohort comprising 192 patients was enrolled for analysis. Throughout observation period, 32.29% of the population died. Key factors such as cardiac involvement, albumin, smoking history, and age displayed substantial prognostic relevance in AAV-ILD. These factors were incorporated to craft a predictive nomogram. Impressively, the model exhibited robust performance, boasting a Harrell's C index of 0.826 and an AUC of 0.940 (95% CI 0.904-0.976). The calibration curves depicted a high degree of harmony between predicted outcomes and actual observations. Significantly enhancing discriminative ability compared to the ILD-GAP model, the nomogram was validated through the IDI, NRI, and likelihood ratio test. DCA underscored the superior predictive value of the predictive model over the ILD-GAP model. The internal validation further affirmed this efficacy, with a mean Harrell's C-index of 0.815 for the predictive model. The nomogram model can be employed to predict the prognosis of patients with AAV-ILD. Moreover, the model performance is satisfactory. In the future, external datasets could be utilized for external validation.

Clinical significance of acute exacerbation in interstitial lung disease with antineutrophil cytoplasmic antibody: an indicator of poor prognosis

BACKGROUND

The association between interstitial lung disease (ILD) and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has been increasingly recognized in recent years. The clinical features and prognostic differences between AAV-associated ILD and isolated ANCA-positive idiopathic interstitial pneumonias (IIPs) remain unclear. The purpose of this study was to determine the clinical significance and prognosis of ANCA-positive ILD to further guide clinical management.

METHODS

This study retrospectively reviewed the data of 379 ILD patients with available ANCA results and ultimately analysed 49 ANCA-positive patients. AAV diagnosis was based on the 2012 revised Chapel Hill Consensus Conference (CHCC) criteria, and 33 of 49 patients were diagnosed with microscopic polyangiitis (MPA). The baseline clinical information and laboratory parameters were collected and analysed at each patient's initial diagnosis.

RESULTS

Among 49 ANCA-positive ILD patients, the high-resolution computed tomography (HRCT) pattern was mainly usual interstitial pneumonia (UIP) (59.18%), followed by nonspecific interstitial pneumonia (NSIP) (26.53%). The C-reactive protein (CRP) level (43.89± 40.61 versus 18.74± 20.05, p = 0.028) and erythrocyte sedimentation rate (ESR) (71.97± 42.73 versus 40.69± 28.46, p = 0.011) were significantly higher in the MPA-ILD group than in the ANCA-IIP group. Haemoglobin (113.09 ± 24.47 versus 132.19± 13.34, p = 0.006) and albumin (32.95± 5.84 versus 36.52± 3.94, p = 0.032) levels were significantly lower. Survival was shorter among MPA-ILD patients than among ANCA-IIP patients [hazard ratio (HR) 3.38, 95% confidence interval (CI) 1.32-8.67, p = 0.040]. In the multivariable Cox analysis, a diagnosis of MPA (HR 3.91, 95% CI 1.07-14.08, p = 0.038) and acute exacerbation (AE) of ILD (HR 9.43, 95% CI 2.89-30.30, p < 0.001) were significantly independently associated with shorter survival in ANCA-positive ILD patients, and the NSIP pattern (HR 0.07, 95% CI 0.01-0.41, p = 0.003) was independently associated with prolonged survival.

CONCLUSION

ANCA-ILD patients mostly have myeloperoxidase (MPO)-ANCA positivity and an MPA diagnosis. Survival was shorter among MPA-ILD patients than among ANCA-IIP patients. Respiratory failure and AE were associated with poorer prognosis. Early antifibrotic treatment may be a reasonable treatment option in fibrotic ILD patients with ANCA positivity.