Novel Advanced Impedance Metrics on Impedance-pH Testing Predict Lung Function Decline in Idiopathic Pulmonary Fibrosis

Data from the INMARK trial were used to investigate the feasibility and validity of home spirometry as a measure of lung function decline in patients with idiopathic pulmonary fibrosis (IPF).Subjects with IPF and preserved forced vital capacity (FVC) were randomised to receive nintedanib or placebo for 12 weeks followed by open-label nintedanib for 40 weeks. Clinic spirometry was conducted at baseline and weeks 4, 8, 12, 16, 20, 24, 36 and 52. Subjects were asked to perform home spirometry at least once a week and ideally daily. Correlations between home- and clinic-measured FVC and rates of change in FVC were assessed using Pearson correlation coefficients.In total, 346 subjects were treated. Mean adherence to weekly home spirometry decreased over time but remained above 75% in every 4-week period. Over 52 weeks, mean adherence was 86%. Variability in change from baseline in FVC was greater when measured by home rather than clinic spirometry. Strong correlations were observed between home- and clinic-measured FVC at all time-points (r=0.72 to 0.84), but correlations between home- and clinic-measured rates of change in FVC were weak (r=0.26 for rate of decline in FVC over 52 weeks).Home spirometry was a feasible and valid measure of lung function in patients with IPF and preserved FVC, but estimates of the rate of FVC decline obtained using home spirometry were poorly correlated with those based on clinic spirometry.

Download Full-text

Circulating fibrocytes are not disease-specific prognosticators in idiopathic pulmonary fibrosis

European Respiratory Journal ◽

10.1183/13993003.00172-2021 ◽

2021 ◽

pp. 2100172

Author(s):

Iain D. Stewart ◽

Henry Nanji ◽

Grazziela Figueredo ◽

William A. Fahy ◽

Toby M. Maher ◽

...

Keyword(s):

Lung Function ◽

Idiopathic Pulmonary Fibrosis ◽

Pulmonary Fibrosis ◽

Disease Progression ◽

Hazard Ratio ◽

Mortality Data ◽

Prospective Clinical Study ◽

Lung Function Decline ◽

Mixed Effect ◽

Circulating Fibrocytes

ObjectiveCirculating fibrocytes are elevated in idiopathic pulmonary fibrosis, but the relationship between fibrocyte level with lung function decline and outcomes is lacking replication in prospective clinical study. We aim to validate the utility of circulating fibrocyte levels as a prognostic biomarker in idiopathic pulmonary fibrosis.MethodsWe tested associations between circulating fibrocyte levels, mortality, disease progression and longitudinal lung function in a well-defined prospective observational study of pulmonary fibrosis (PROFILE; NCT01134822). A subset of recruited participants had blood samples processed for fibrocyte measurement, with flow cytometry based on CD45 and collagen-I gating. Associations were tested using univariable and multivariable generalised linear models. Mortality data were subsequently combined with an independent cohort in a mixed-effect multilevel analysis.ResultsIn 102 participants with idiopathic pulmonary fibrosis, a previously defined mortality risk threshold of 5% circulating fibrocytes was not reproducible. An empirically defined cutpoint of 2.22% was associated with a greater risk of overall mortality in adjusted analysis (Hazard Ratio 2.24 95% CI 1.06-4.72). A 2.5 fold greater risk of mortality was supported in a pooled analysis with a historic cohort for a larger sample of 162 participants with idiopathic pulmonary fibrosis (Hazard Ratio 2.49 95% CI 2.41-2.56). We found no association of fibrocytes with lung function or disease progression.ConclusionsIn a large sample of circulating fibrocytes from people with idiopathic pulmonary fibrosis, levels of 2.22% or above were associated with greater mortality, but not with disease related decline in lung function.

Download Full-text