Chest
Volume 108, Issue 2, August 1995, Pages 305-310
Journal home page for Chest

Clinical Investigations; Articles; Interstitial Lung Disease
Changes in Pulmonary Function Test Results After 1 Year of Therapy as Predictors of Survival in Patients With Idiopathic Pulmonary Fibrosis

https://doi.org/10.1378/chest.108.2.305Get rights and content

The study group consisted of 58 patients with idiopathic pulmonary fibrosis (IPF) recognized between 1970 and 1991 who were treated for their pulmonary disease, survived for at least 1 year from the time of initiation of treatment, and had forced vital capacity (FVC) measurements at the time of diagnosis and 9 to 15 months later. Forty-four of the patients also had a single-breath diffusing capacity (Dsb) measured initially and after 9 to 15 months of treatment and 33 patients had an arterial blood gas, breathing room air at the time of diagnosis and 9 to 15 months into therapy. Patients' conditions were classified as improved, unchanged, or worse after the year of treatment based on each of the three pulmonary function tests. A ≥ 10% increase in FVC, ≥20% increase in Dsb, and ≥5 mm Hg decrease in alveolar-arterial difference in oxygen partial pressure [P(A-a)O2] defined improved function. A ≥10% decrease in FVC, ≥20% decrease in Dsb, and ≥5 mm Hg increase in P(A-a)O2 defined worse function. Patients with <10% change in FVC, <20% change in Dsb, and <5 mm Hg change in P(A-a)O2 were regarded as having unchanged conditions. Kaplan-Meier survival plots and the Cox proportional hazard regression model were used to analyze survival time in relation to change in pulmonary function after 1 year of therapy. Patients with an improved or unchanged FVC at 1 year had no difference in survival (p=0.75), but both showed enhanced survival compared with patients with a ≥10% reduction in FVC with 1 year of treatment (p<0.001). Patients with an improved or unchanged Dsb at 1 year also had no difference in survival (p=0.21) but again, both showed enhanced survival compared with patients with ≥20% decrease in Dsb with 1 year of treatment (p<0.001). Changes in gas exchange after 1 year of treatment did not correlate with survival in the three groups. There was a trend for longer survival in improved patients compared with those with worsening gas exchange, but the p value was not significant at 0.17. We conclude that changes in the FVC and Dsb after 1 year of treatment are strongly predictive of duration of survival in patients with IPF. (CHEST 1995; 108:305-310)

Section snippets

Study Population

All patients 18 years of age or greater seen at Virginia Mason Medical Center (VMMC), Seattle, between 1970 and 1991 with a diagnosis of pulmonary fibrosis by diagnostic computer ICD-9 code and/or pathology report were reviewed. A diagnosis of IPF was established if the following three criteria were met: (1) the chest radiograph showed a diffuse reticulonodular infiltrate; (2) a lung biopsy (either open or transbronchial) specimen demonstrated interstitial fibrosis in the absence of granuloma,

Results

The records of 905 patients with ICD-9 code and/or pathology reports of “pulmonary fibrosis” were reviewed. Five hundred three patients had focal radiographic change rather than diffuse parenchymal disease. Two hundred forty-two patients with diffuse pulmonary fibrosis had identifiable causes of the pulmonary scarring, including 102 patients with collagen vascular disease, 52 patients with postinfectious pulmonary fibrosis, 30 patients with sarcoidosis, 20 patients with postirradiation change,

Discussion

Previous clinical studies have emphasized pretreatment variables that are predictive of a beneficial response to treatment. A duration of disease of less than 1 year, more cellular reaction with less fibrosis on open lung biopsy specimen, and a bronchoalveolar lavage cell population with increased proportions of lymphocytes have each been correlated with better response to treatment.6, 7, 8, 9, 10, 11

This study was conducted to assess the ability of changes in pulmonary function testing at 1

References (13)

There are more references available in the full text version of this article.

Cited by (122)

  • Pathology and natural history of organ fibrosis

    2019, Current Opinion in Pharmacology
    Citation Excerpt :

    However, these physiological patterns are in general characterized by restrictive function with decreased lung capacities and gas diffusion [10]. The lung function tests alone are better prognostic determinants than the radiological or pathological diagnosis [11]. Current pathogenetic hypotheses on DPF include a putative genetic predisposition where gene expression is triggered by repetitive epigenetic factors resulting in abnormal reparative tissue process [12].

  • Idiopathic pulmonary fibrosis: Gender-age-physiology index stage for predicting future lung function decline

    2016, Chest
    Citation Excerpt :

    Notably, our analysis reached statistical significance whereas the previous analysis exhibited only marginal significance. Various degrees of decline in FVC and Dlco are well known for predicting greater mortality in patients with IPF.4-10 Our study highlights that interval changes in pulmonary function may add clinically useful prognostic information to the GAP Index stage.

View all citing articles on Scopus
View full text