Long-term clinical course and outcomes of patients with microscopic polyangiitis-associated interstitial lung disease

Min Jee Kim; Donghee Lee; Jooae Choe; Jin Woo Song

doi:10.3389/fphar.2023.1064307

Long-term clinical course and outcomes of patients with microscopic polyangiitis-associated interstitial lung disease

Front Pharmacol. 2023 Jan 30:14:1064307. doi: 10.3389/fphar.2023.1064307. eCollection 2023.

Authors

Min Jee Kim¹, Donghee Lee², Jooae Choe³, Jin Woo Song⁴

Affiliations

¹ Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
² University of Ulsan College of Medicine, Seoul, South Korea.
³ Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
⁴ Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.

Abstract

Background: Interstitial lung disease (ILD) is a significant complication associated with microscopic polyangiitis (MPA) that has a poor prognosis. However, the long-term clinical course, outcomes, and prognostic factors of MPA-ILD are not well defined. Hence, this study aimed to investigate the long-term clinical course, outcomes, and prognostic factors in patients with MPA-ILD. Methods: Clinical data of 39 patients with MPA-ILD (biopsy proven cases, n = 6) were retrospectively analyzed. High resolution computed tomography (HRCT) patterns were assessed based on the 2018 idiopathic pulmonary fibrosis diagnostic criteria. Acute exacerbation (AE) was defined as the worsening of dyspnea within 30 days, with new bilateral lung infiltration that is not fully explained by heart failure or fluid overload and that does not have identified extra-parenchymal causes (pneumothorax, pleural effusion, or pulmonary embolism). Results: The median follow-up period was 72.0 months (interquartile range: 44-117 months). The mean age of the patients was 62.7 years and 59.0% were male. Usual interstitial pneumonia (UIP) and probable usual interstitial pneumonia patterns on high resolution computed tomography were identified in 61.5 and 17.9% of the patients, respectively. During the follow-up, 51.3% of patients died, and the 5- and 10-year overall survival rates were 73.5% and 42.0%, respectively. Acute exacerbation occurred in 17.9% of the patients. The non-survivors had higher neutrophil counts in bronchoalveolar lavage (BAL) fluid and more frequent acute exacerbation than the survivors. In the multivariable Cox analysis, older age (hazard ratio [HR], 1.07; 95% confidence interval [CI], 1.01-1.14; p = 0.028) and higher BAL counts (HR, 1.09; 95% CI, 1.01-1.17; p = 0.015) were found to be the independent prognostic factors associated with mortality in patients with MPA-ILD. Conclusion: During the 6 years-follow-up, about half of patients with MPA-ILD died and approximately one-fifth experienced acute exacerbation. Our results suggest that older age and higher BAL neutrophil counts mean poor prognosis in patients with MPA-ILD.

Keywords: interstitial lung disease; microscopic polyangiitis; prognosis; risk factor; survival.

Grants and funding

This study was supported by grants from the Basic Science Research Program (NRF-2022R1A2B5B02001602) and the Bio and Medical Technology Development Program (NRF-2022M3A9E4082647) of the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, South Korea, and also supported by the National Institute of Health research project (2021ER120701) and by Korea Environment Industry and Technology Institute through Core Technology Development Project for Environmental Diseases Prevention and Management Program funded by Korea Ministry of Environment (ARQ202201450001), South Korea.