Differences between acute exacerbations of idiopathic pulmonary fibrosis and other interstitial lung diseases.

Interstitial lung diseases (ILDs) comprise a wide group of pulmonary parenchymal disorders. These patients may experience acute respiratory deteriorations of their respiratory condition, termed “acute exacerbation” (AE). Incidence of AE-ILD seems to be lower than idiopathic pulmonary fibrosis (IPF), but prognosis and prognostic factors are largely unrecognized. We retrospectively analyzed a cohort of 158 consecutive adult patients hospitalized for AE-ILD in two Italian University hospitals from 2009 to 2016. Patients included in the analysis has been divided into two groups: non-IPF (62%) and IPF (38%). Among ILDs included in the non-IPF group, the most frequent diagnoses were non-specific interstitial pneumonia (NSIP) (42%) and connective tissue disease (CTD)-ILD (20%). Mortality during hospitalization was significantly different between the two groups, respectively 19% in non-IPF group and 43% in IPF group. AEs of ILDs are difficult-to-predict events and are burdened by relevant mortality. Increased inflammatory markers with neutrophilia on differential blood cell count (HR 1.02 [CI 1.01 – 1.04]), presence of pulmonary hypertension (HR 1.85 – [CI 1.17 – 2.92]) and diagnosis of IPF (HR 2.31 [CI 1.55 – 3.46]) resulted negative prognostic factors in our analysis, while lymphocytosis on differential count seemed to act as a protective prognostic factor (OR 0.938 [CI 0.884 – 0.995]). Further prospective, large-scale, real-world data are needed to support and confirm the impact of our findings.