[Interstitial pneumonia with autoimmune features: monocentric prospective study]

To study demographic, clinical, serological and morphological features of interstitial pneumonia with autoimmune features (IPAF), compare survival in IPAF and interstitial lung disease in connective tissue diseases (CTD-ILD), and identify predictors of mortality and transformation to CTD in the IPAF group.

The IPAF group included 48 patients (75.0% women, median age 57.5 years), CTD-ILD - 49 patients (79.6% women, median age 60.0 years). The analysis of demographic, clinical, laboratory and instrumental data was performed, as well as comparison of survival with the Kaplan-Meier method and the log-rank test in the IPAF and CTD-ILD groups. In the IPAF group, predictors of mortality and the development of CTD were studied with multivariate regression analysis.

Duration of observation period did not differ significantly in the IPAF and CTD-ILD groups (40.0 and 37.0 months, respectively). Clinical criteria of IPAF were observed in 25 (52.1%) patients, serological - in 44 (91.7%), morphological - in 44 (91.7%). Mortality in the IPAF group was significantly higher than in the CTD-ILD group (29.2 and 6.1%, respectively; p=0.023). The presence of diabetes mellitus, CT-pattern of usual interstitial pneumonia, and an initial low forced vital capacity value were independent predictors of mortality in the IPAF group. During the observation period, the development of CTD was noted in 4 (8.3%) patients with IPAF. The independent predictor of the CTD development was the increased C-reactive protein level.

IPAF is characterized by a lower survival rate compared to CTD-ILD, and a relatively low risk of CTD transformation.