Chest
Original Research: Diffuse Lung DiseaseIdiopathic Pulmonary Fibrosis: Gender-Age-Physiology Index Stage for Predicting Future Lung Function Decline
Section snippets
Patients
We identified subjects with IPF (diagnosed according to results of lung biopsy or CT scan [as previously described])1, 21 through review of interstitial lung disease databases at the Royal Brompton and Harefield National Health Service Foundation Trust, National Jewish Health, and the University of Michigan Health System from 1981 to 2008. For each patient, age, sex, and each pulmonary function test (PFT) were captured, with PFTs performed as described.22, 23, 24, 25 Patients with missing
Patient Population and Survival Comparisons
From the interstitial lung disease databases, 734 patients with IPF were identified; 657 had FVC and Dlco data available at baseline and were included in the present analysis. Patient characteristics for the included group as a whole and according to GAP stage are shown in Table 1. Overall, 70% were men, and the mean age was 62.9 years at the time of the baseline PFT. The mean ± SD percent-predicted baseline FVC was 68.0 ± 17.0, and for Dlco it was 45.7 ± 16.0.
For the combined end point of
Discussion
Pulmonary function trajectories were modeled in a large retrospective cohort of patients with IPF seen at 3 referral centers to determine if the GAP Index stage, a validated estimate of mortality risk, was also predictive of the future rate of decline in pulmonary function. Our findings are most notable for the lack of a consistently larger absolute or relative decline in FVC or Dlco for a particular GAP stage over 2 years of follow-up. Several modestly significant P values were reported
Conclusions
Our findings showed that pulmonary function trajectory does not vary based on disease severity as defined according to the GAP Index. We also found that 6-month declines in pulmonary function may add prognostic value to the baseline GAP stage. Further validation of our findings in additional cohorts is warranted, as well as a search for novel markers of future disease progression not tied to pulmonary function variables.
Acknowledgments
Author contributions: M. L. S. and K. R. F conceived and designed the study, had full access to all of the data, and take responsibility for the integrity of the data and the accuracy of the data analysis. M. L. S., M. X., and Y. Z. analyzed the data with supervision and assistance from S. M. and K. R.; F. N. T., K. K. B., A. U. W., S. L. S., and F. J. M. contributed data; and M. L. S. and K. R. F. prepared the manuscript. All other authors revised the manuscript and approved the final draft.
References (29)
- et al.
Changes in pulmonary function test results after 1 year of therapy as predictors of survival in patients with idiopathic pulmonary fibrosis
Chest
(1995) - et al.
Pirfenidone in patients with idiopathic pulmonary fibrosis (CAPACITY): two randomised trials
Lancet
(2011) - et al.
Predicting pulmonary fibrosis disease course from past trends in pulmonary function
Chest
(2014) - et al.
Pulmonary function and survival in idiopathic vs secondary usual interstitial pneumonia
Chest
(2014) - et al.
An official ATS/ERS/JRS/ALAT statement: idiopathic pulmonary fibrosis: evidence-based guidelines for diagnosis and management
Am J Respir Crit Care Med
(2011) - et al.
Acute exacerbations of idiopathic pulmonary fibrosis
Am J Respir Crit Care Med
(2007) - et al.
Clinical course and prediction of survival in idiopathic pulmonary fibrosis
Am J Respir Crit Care Med
(2011) - et al.
Changes in clinical and physiologic variables predict survival in idiopathic pulmonary fibrosis
Am J Respir Crit Care Med
(2003) - et al.
Idiopathic pulmonary fibrosis: prognostic value of changes in physiology and six-minute-walk test
Am J Respir Crit Care Med
(2006) - et al.
Prognostic implications of physiologic and radiographic changes in idiopathic interstitial pneumonia
Am J Respir Crit Care Med
(2003)
Physiology is a stronger predictor of survival than pathology in fibrotic interstitial pneumonia
Am J Respir Crit Care Med
Predicting survival in idiopathic pulmonary fibrosis: scoring system and survival model
Am J Respir Crit Care Med
Fibrotic idiopathic interstitial pneumonia: the prognostic value of longitudinal functional trends
Am J Respir Crit Care Med
Ascertainment of individual risk of mortality for patients with idiopathic pulmonary fibrosis
Am J Respir Crit Care Med
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Interstitial Lung Disease and Sarcoidosis
2023, Clinics in Chest MedicineFrench practical guidelines for the diagnosis and management of idiopathic pulmonary fibrosis – 2021 update. Full-length version
2023, Respiratory Medicine and ResearchForced vital capacity trajectories in patients with idiopathic pulmonary fibrosis: a secondary analysis of a multicentre, prospective, observational cohort
2022, The Lancet Digital HealthCitation Excerpt :As idiopathic pulmonary fibrosis progresses, missed spirometry visits promote survivor bias by raising the mean FVC because missing values are associated with exacerbation of the condition or mortality among patients.6–8 To mitigate this bias, previous studies have used various methods to adjust for data loss.4–7,10,11 However, these approaches can introduce alternative biases, making it difficult to accurately measure and model the disease trajectory of idiopathic pulmonary fibrosis over extended time periods.6–9,12,13
French practical guidelines for the diagnosis and management of IPF – 2021 update, full version
2022, Revue des Maladies RespiratoiresDifferent Faces of Idiopathic Pulmonary Fibrosis With Preserved Forced Vital Capacity
2022, Archivos de Bronconeumologia
FUNDING/SUPPORT: This study was funded by the National Institutes of Health [Grant K24 HL111316 to Dr Flaherty and Grant T32 HL007749-22].