Combination of computed tomography imaging pattern and severity of respiratory failure as factors associated with prognosis for acute exacerbation of idiopathic chronic fibrosing interstitial pneumonia

BACKGROUND AND OBJECTIVES: The prognosis of idiopathic chronic fibrotic interstitial pneumonitis (CFIP) in patients with acute exacerbation (AE) is variable. We examined whether the imaging pattern on thoracic computed tomography (CT) or the severity of respiratory failure with AE-CFIP is associated with short-term prognosis. METHODS: Patients admitted to two university hospitals were retrospectively analyzed and divided into derivation and validation cohorts. The distribution of newly appearing parenchymal abnormalities on thoracic CT was classified into peripheral, multifocal, and diffuse patterns. Respiratory failure was defined as severe if a fraction of inspired oxygen ≥ 0.5 was required to maintain percutaneous oxygen saturation ≥ 90% on admission. Factors associated with 90 day-mortality were analyzed using univariate and Cox proportional hazard regression. RESULTS: In 59 patients with AE-CFIP of the derivation cohort, diffuse pattern on CT was associated with higher mortality within 90 days (43%) than peripheral/multifocal pattern (17%, p = 0.03). Additionally, compared with non-severe failure, severe respiratory failure was associated with higher mortality (47% vs. 21%, p = 0.06). Cox proportional hazard regression analysis demonstrated that a combination of diffuse pattern on CT and severe respiratory failure was associated with the poorest prognosis (hazard ratio [HR] 3.51 [interquartile range 1.26–9.80], p = 0.016) in the derivation cohort, which was confirmed in the validation cohort (n = 31, HR 4.30 [interquartile range 1.51–12.2], p = 0.006). CONCLUSION: The combination of imaging pattern on thoracic CT and severity of respiratory failure was associated with the prognosis of idiopathic AE-CFIP.