Clinical characteristics of idiopathic pulmonary fibrosis patients with gender, age, and physiology staging at Okinawa Chubu Hospital.

Background: Gender, age, and physiology (GAP) staging was recently advocated for idiopathic pulmonary fibrosis (IPF). However, clinical findings of GAP staging for IPF are limited. We aimed to investigate the clinical characteristics of IPF patients according to GAP staging in our hospital.

Methods: We retrospectively reviewed patient medical records and chest high-resolution computed tomography (HRCT) images from June 1, 2002, to December 31, 2012.

Results: We identified 54 IPF patients with [36 men; mean age: 71 years (range, 53-85 years)]. Mean fibrosis and ground glass opacity (GGO) scores were 1.9 (0-4) and 1.6 (1-3.3), respectively. Mean percent predicted forced vital capacity (% FVC), percent predicted diffusing capacity of the lung for carbon monoxide (% DLco) were 70.6 (6.4-114.3), 49.2 (15-105.9), respectively. Cox proportional hazards model showed that gender, percent predicted diffusing capacity of the lung for carbon monoxide (% DLco), and composite physiologic index (CPI) were strong predictors of mortality. Stage III patients had more pulmonary hypertension (50% vs. 23%, 0%) and progressive modified Medical Research Council (mMRC) changes at 1 year (1.3 vs. 0.6, 1.1; P=0.07) compared with other stages.

Conclusions: In our cohort, GAP staging was useful for evaluating IPF severity. Stage III patients might had more pulmonary hypertension and progressive dyspnea. Multicenter analyses are warranted to confirm these findings.