- Title
- Eligibility for anti-fibrotic treatment in idiopathic pulmonary fibrosis depends on the predictive equation used for pulmonary function testing
- Creator
- Burgess, Andrew; Goon, Ken; Brannan, John D.; Attia, John; Palazzi, Kerrin; Oldmeadow, Christopher; Corte, Tamera J.; Glaspole, Ian; Goh, Nicole; Keir, Gregory; Allan, Heather; Chapman, Sally; Cooper, Wendy; Ellis, Samantha; Hopkins, Peter; Moodley, Yuben; Reynolds, Paul; Zappala, Chris; Macansh, Sacha; Grainge, Cristopher
- Relation
- Respirology Vol. 24, Issue 10, p. 988-995
- Publisher Link
- http://dx.doi.org/10.1111/resp.13540
- Publisher
- Wiley-Blackwell
- Resource Type
- journal article
- Date
- 2019
- Description
- Background and Objective: Publicly funded therapy for idiopathic pulmonary fibrosis (IPF) relies on percentage predicted values from pulmonary function testing, for example Australian patients must have a forced vital capacity ≥50% (%FVC), transfer factor of the lung for carbon monoxide ≥ 30% (%TLco) and forced expiratory volume in 1 s (FEV₁)/FVC ratio > 0.7. Despite defined cut-off values, no jurisdiction prescribes a reference equation for use; multiple equations exist. We hypothesized that access to subsidized treatment varies depending on the chosen equation. The %FVC and %TLco from different commonly used reference equations across general respiratory patients, and IPF-specific patients, were compared. Methods: FVC and TLco measurements from a large general respiratory laboratory and the Australian Idiopathic Pulmonary Fibrosis Registry (AIPFR) database were analysed using multiple equations. Differences between %FVC and %TLco for each equation were calculated, with particular interest in classification of patients (%) at the threshold for subsidized treatment. Results: A total of 20 378 general respiratory database results were analysed. The %FVC ≥ 50% increased from 86% with the Roca equation to 96% with Quanjer (European Coal and Steal Community, ECSC) and %TLco≥30% increased from 91% with Paoletti to 98% with Thompson. However, overall increase in eligibility for subsidized treatment was modest, varying from 48.2% to 49.2%. A total of 545 AIPFR database results were analysed. The %FVC ≥ 50% increased from 73% with Roca to 94% with Quanjer (ECSC) and %TLco≥30% increased from 87% with Paoletti to 96% with Miller. Overall eligibility for subsidized treatment in the AIPFR group varied from 73.6% to 82.8% between surveyed interstitial lung disease (ILD) centres based entirely on the equation used. Conclusion: Substantial variability exists between reference equations, impacting access to subsidized treatment. Treating clinicians should be aware of this when assessing patients around public funding thresholds.
- Subject
- fibrosis; lung function; predicted equations; treatment; SDG 3; Sustainable Development Goals
- Identifier
- http://hdl.handle.net/1959.13/1443223
- Identifier
- uon:41920
- Identifier
- ISSN:1323-7799
- Language
- eng
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