Global Lung Function Initiative equations improve interpretation of FEV<sub>1</sub> decline among patients with cystic fibrosis

Stanojevic, Sanja; Bilton, Diana; McDonald, Alexandra; Stocks, Janet; Aurora, Paul; Prasad, Ammani; Cole, Tim; Davies, Gwyneth

doi:10.1183/09031936.00187314

Cited by 26 publications

(19 citation statements)

References 10 publications

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“…There is mounting evidence that NE is a key element driving inflammation induced lung damage in CF [6]. Sputum NE activity is a predictor of future lung function decline [10].…”

Section: Discussionmentioning

confidence: 99%

“…Despite similarities in pathophysiology, outcomes differ between the two diseases, with the course of lung disease being more favourable for PCD patients [3][4][5][6]. A number of factors have been proposed to account for this difference, including better cough clearance in PCD, as the ciliary abnormalities in PCD do not result in the same degree of airway surface liquid depletion seen in CF [1,2].…”

Section: Introductionmentioning

confidence: 99%

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Changes in airway inflammation during pulmonary exacerbations in patients with cystic fibrosis and primary ciliary dyskinesia

et al. 2015

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Lung disease in patients with both primary ciliary dyskinesia (PCD) or cystic fibrosis (CF) is associated with impaired mucociliary clearance; however, clinical outcomes are typically worse in CF patients. We assessed whether CF and PCD patients differ in inflammatory response in the airways during pulmonary exacerbation.We first studied clinically stable PCD patients with a spectrum of bacterial pathogens to assess inflammatory response to different pathogens. Subsequently, PCD and CF patients with similar bacterial pathogens were studied at the time of a pulmonary exacerbation and after 21 days of antibiotics treatment. Qualitative and quantitative microbiology, cell counts, interleukin-8 concentrations, and neutrophil elastase activity were assessed in sputum samples obtained before and after treatment.In stable PCD patients, no significant differences were found in sputum inflammatory markers between individuals colonised with different bacterial pathogens. Pulmonary exacerbation severity assessed by a pulmonary exacerbation score and lung function decline from their previous baseline did not differ between CF and PCD patients. Bacterial density for Staphylococcus aureus and Haemophilus influenzae was higher in CF versus PCD ( p<0.05), but absolute neutrophil counts were higher in PCD patients ( p=0.02). While sputum elastase activity was similar in PCD and CF at the time of exacerbation, it decreased with antibiotic therapy in PCD ( p<0.05) but not CF patients.PCD patients differ from those with CF in their responses to treatment of pulmonary exacerbations, with higher neutrophil elastase activity persisting in the CF airways at the end of treatment. @ERSpublications PCD patients differ from those with CF in their responses to treatment of pulmonary exacerbations

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“…There is mounting evidence that NE is a key element driving inflammation induced lung damage in CF [6]. Sputum NE activity is a predictor of future lung function decline [10].…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Changes in airway inflammation during pulmonary exacerbations in patients with cystic fibrosis and primary ciliary dyskinesia

et al. 2015

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“…The assumption is that FEV 1 decline becomes less severe as a person with CF ages (Figure C2); this is indicative of the “ceiling” and “floor” effects that have been noted with FEV 1 decline, as younger individuals with higher lung function tend to have steeper decline than older individuals with lower lung function who exhibit the “floor” effect(21). An alternative is to model FEV 1 progression with splines(15) (28) (29). Similar to change point models, this approach provides nonlinear fitting within more precise intervals of age (Figure D1) and can identify intervals of severe decline (Figure D2).…”

Section: Fev1 In Cf Epidemiologic Studies: Analytic Approaches Formentioning

confidence: 99%

Use of FEV1 in cystic fibrosis epidemiologic studies and clinical trials: A statistical perspective for the clinical researcher

Szczesniak

Heltshe

Stanojevic

et al. 2017

Journal of Cystic Fibrosis

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Background Forced expiratory volume in 1 second (FEV1) is an established marker of cystic fibrosis (CF) disease progression that is used to capture clinical course and evaluate therapeutic efficacy. The research community has established FEV1 surveillance data through a variety of observational data sources such as patient registries, and there is a growing pipeline of new CF therapies demonstrated to be efficacious in clinical trials by establishing improvements in FEV1. Results In this review, we summarize from a statistical perspective the clinical relevance of FEV1 based on its association with morbidity and mortality in CF, its role in epidemiologic studies of disease progression and comparative effectiveness, and its utility in clinical trials. In addition, we identify opportunities to advance epidemiologic research and the clinical development pipeline through further statistical considerations. Conclusions Our understanding of CF disease course, therapeutics, and clinical care has evolved immensely in the past decades, in large part due to the thoughtful application of rigorous research methods and meaningful clinical endpoints such as FEV1. A continued commitment to conduct research that minimizes the potential for bias, maximizes the limited patient population, and harmonizes approaches to FEV1 analysis while maintaining clinical relevance, will facilitate further opportunities to advance CF care.

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“…This is in part due to the demographic of our centre which has a relatively young adult population. A previous study found a near-linear %FEV 1 decline from childhood to adulthood with GLI equation, whereas there was accelerated %FEV 1 decline during adolescence and young adulthood when %FEV 1 was calculated with Knudson equation 21 . One advantage of using the GLI equation, which is seamless across all ages, is that it improves the interpretation of %FEV 1 decline 21, 22 .…”

Section: Discussionmentioning

confidence: 81%

“…A previous study found a near-linear %FEV 1 decline from childhood to adulthood with GLI equation, whereas there was accelerated %FEV 1 decline during adolescence and young adulthood when %FEV 1 was calculated with Knudson equation 21 . One advantage of using the GLI equation, which is seamless across all ages, is that it improves the interpretation of %FEV 1 decline 21, 22 . Another advantage is that %FEV 1 decline can be adjusted for baseline %FEV 1 using ESCF reference values (since the ESCF values for %FEV 1 decline were calculated using the GLI equation 20 ).…”

Section: Discussionmentioning

confidence: 81%

Using different methods to process forced expiratory volume in one second (FEV1) data can impact on the interpretation of FEV1 as an outcome measure to understand the performance of an adult cystic fibrosis centre: A retrospective chart review

et al. 2018

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Background: Forced expiratory volume in one second (FEV 1) is an important cystic fibrosis (CF) prognostic marker and an established endpoint for CF clinical trials. FEV 1 is also used in observation studies, e.g. to compare different centre’s outcomes. We wished to evaluate whether different methods of processing FEV 1 data can impact on a centre’s outcome. Methods: This is a single-centre retrospective analysis of routinely collected data from 2013-2016 which included 208 adults with CF. Year-to-year %FEV 1 change was calculated by subtracting best %FEV 1 at Year 1 from Year 2 (i.e. negative values indicate %FEV 1 decline), and compared using Friedman test. Three methods were used to process %FEV 1 data. First, %FEV 1 calculated with Knudson equation was extracted directly from spirometer machines. Second, FEV 1 volume were extracted then converted to %FEV 1 using clean height data and Knudson equation. Third, FEV 1 volume were extracted then converted to %FEV 1 using clean height data and GLI equation. In addition, %FEV 1 decline calculated using GLI equation was adjusted for baseline %FEV 1 to understand the impact of case-mix adjustment. Results: There was a trend of reduction in %FEV 1 decline with all three data processing methods but the magnitude of %FEV 1 decline differed. Median change in %FEV 1 for 2013-2014, 2014-2015 and 2015-2016 was –2.0, –1.0 and 0.0 respectively using %FEV 1 in Knudson equation whereas the median change was –1.1, –0.9 and –0.3 respectively using %FEV 1 in the GLI equation. A statistically significant p-value (0.016) was only obtained when using %FEV 1 in Knudson equation extracted directly from spirometer machines. Conclusions: Although the trend of reduction in %FEV 1 decline was robust, different data processing methods yielded varying results when %FEV 1 decline was compared using a standard related group non-parametric statistical test. Observational studies with %FEV 1 decline as an outcome measure should carefully consider and clearly specify the data processing methods used.

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Global Lung Function Initiative equations improve interpretation of FEV₁ decline among patients with cystic fibrosis

Cited by 26 publications

References 10 publications

Changes in airway inflammation during pulmonary exacerbations in patients with cystic fibrosis and primary ciliary dyskinesia

Changes in airway inflammation during pulmonary exacerbations in patients with cystic fibrosis and primary ciliary dyskinesia

Use of FEV1 in cystic fibrosis epidemiologic studies and clinical trials: A statistical perspective for the clinical researcher

Using different methods to process forced expiratory volume in one second (FEV1) data can impact on the interpretation of FEV1 as an outcome measure to understand the performance of an adult cystic fibrosis centre: A retrospective chart review

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Global Lung Function Initiative equations improve interpretation of FEV1 decline among patients with cystic fibrosis

Cited by 26 publications

References 10 publications

Changes in airway inflammation during pulmonary exacerbations in patients with cystic fibrosis and primary ciliary dyskinesia

Changes in airway inflammation during pulmonary exacerbations in patients with cystic fibrosis and primary ciliary dyskinesia

Use of FEV1 in cystic fibrosis epidemiologic studies and clinical trials: A statistical perspective for the clinical researcher

Using different methods to process forced expiratory volume in one second (FEV1) data can impact on the interpretation of FEV1 as an outcome measure to understand the performance of an adult cystic fibrosis centre: A retrospective chart review

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Global Lung Function Initiative equations improve interpretation of FEV₁ decline among patients with cystic fibrosis