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

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.

The study included 158 patients with DPLDs. Patient data were examined retrospectively, and survival status was obtained through phone calls.

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 mmHg) and thus with a worse survival rate.

The current study determined that FVC% is important in the prediction of mortality. Moreover, it demonstrated a strong relationship between exercise desaturation and PH.