Patients with interstitial lung disease (ILD) and microscopic polyangiitis (MPA) generally have an overall poor prognosis, with lower percent predicted forced vital capacity (FVC%) representing an independent predictive factor for adverse outcomes, according to study results published in CHEST.

The study included a total of 84 consecutive patients with MPA-ILD and 95 patients with MPA-non-ILD. Researchers collected medical record data for review, including clinical data, pathological findings, laboratory data, results of pulmonary function tests, and outcomes. The researchers also compared clinical characteristics and outcomes data between 80 patients with MPA-ILD and 80 matched patients with idiopathic interstitial pneumonia without myeloperoxidase-anti-neutrophil cytoplasmic antibody-positivity (ILD-alone).

There were more men (66.7% vs 35.8%; P <.01) and former or current smokers (67.9% vs 31.6%; P <.01) in the MPA-ILD group vs the MPA-non-ILD group. A significantly greater number of patients with MPA-ILD also died during the observation period (51 vs 26; P <.01). Similarly, the matched MPA-ILD cohort had a significantly higher mortality compared with the matched ILD-alone arm (P <.01).

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No difference was reported between the matched MPA-ILD and ILD-alone groups with regard to the adverse event (AE) incidence (1-year AE cumulative incidence rate: 7.5% and 5.2%, respectively; P =.75). A lower FVC% in the MPA-ILD group was independently associated with a higher mortality rate (hazard ratio [HR], 0.96 per 1% increase; P <.01) as well as a significantly higher AE incidence rate (HR, 0.96 per 1% increase; P =.01). According to multivariable Cox regression analysis, the development of an AE during the clinical course was associated with a significantly shorter survival (HR, 17.1; 95% CI, 6.04-48.4; P <.001).

Limitations of this study included its retrospective design as well as the inclusion of only patients with MPO-ANCA (antineutrophil cytoplasmic antibody)-positive MPA.

The researchers concluded that the “[e]stablishment of specific management for MPA-ILD and AE is urgently needed.”


Hozumi H, Kono M, Hasegawa H, et al. Clinical significance of interstitial lung disease and its acute exacerbation in microscopic polyangiitis. CHEST. Published online February 8, 2021. doi:10.1016/j.chest.2021.01.083