Rising stars of DPLD survival: FVC and exercise desaturation (a single-center study)

Background/aim: Diffuse parenchymal lung diseases (DPLDs) comprise a broad, heterogeneous group of diseases with common functional characteristics and a common final pathway, usually leading to irreversible fibrosis. We investigated the effects of the physiological and functional parameters and of pulmonary hypertension (PH) on survival in DPLDs. Materials and methods: The study included 158 patients with DPLDs. Patient data were examined retrospectively, and survival status was obtained through phone calls. Results: Patients were divided into five groups according to their diagnosis: idiopathic pulmonary fibrosis (IPF), non-IPF idiopathic interstitial pneumonias, connective tissue diseases, sarcoidosis, and other DPLDs. Median survival was 42.9 months. The significant negative effects of older age, presence of delta saturation (DeltaSat; difference between oxygen saturation at rest and after the 6-min walking test), 6-min walking distance (<350 m), systolic pulmonary artery pressure (sPAP; >50 mmHg), and baseline percentage of diffusing capacity of the lungs for carbon monoxide (<80%) with percentage of forced vital capacity (FVC%; <80%) were detected on survival (P < 0.05). A one-unit decrease in FVC% was related to a 6% increase in mortality. Another unique finding indicated that higher DeltaSat (>10%) correlated strongly with sPAP (>50 mmnHg) and thus with a worse survival rate. Conclusion: The current study determined that FVC% is important in the prediction of mortality. Moreover, it demonstrated a strong relationship between exercise desaturation and PH.