Modified blood cell GAP model as a prognostic biomarker in idiopathic pulmonary fibrosis (max 90 characters incl. spaces)

Abstract

The Gender, Age and Physiology (GAP) model is a simple mortality prediction tool in patients with idiopathic pulmonary fibrosis (IPF) using demographic and physiological variables available at initial evaluation. White blood cell (WBC) variables may have associations with IPF outcomes. We evaluated whether incorporation of blood cell counts in modified GAP (cGAP) models would improve outcome prediction in patients with IPF.This retrospective analysis included pooled data from randomised Phase III trials of pirfenidone in IPF (ASCEND, CAPACITY 004, CAPACITY 006). Study outcomes (IPF progression, all-cause mortality, all-cause hospitalisation, respiratory-related hospitalisation) were evaluated during the initial 1-year period. Shared frailty models were used to evaluate associations between continuous and categorical baseline WBC and red blood cell (RBC) parameters and study outcomes in a bivariate context; and the impact of adding continuous monocyte count (cGAP1) or WBC and RBC parameters (cGAP2) to traditional GAP variables in a multivariable context based on C-statistics changes.Data were pooled from 1247 patients (pirfenidone, n=623; placebo, n=624). Significant associations (bivariate analyses) were: IPF progression with neutrophil and eosinophil counts; all-cause mortality with monocyte and neutrophil counts; all-cause hospitalisation with monocyte count, neutrophil count and haemoglobin level; and respiratory-related hospitalisation with monocyte count, neutrophil count and haemoglobin level. In multivariate analyses, C-statistics were highest for the cGAP2 model for each of the outcomes.Modified GAP models incorporating monocyte counts alone or plus other WBC and RBC variables may be useful to improve prediction of outcomes in patients with IPF.ClinicalTrials.gov identifiersNCT01366209;NCT00287716;NCT00287729.