Andrew Burgess1, Ken Goon1,2, John D Brannan1, John Attia1,3, Kerrin Palazzi3, Christopher Oldmeadow3, Tamera J Corte4,5,6, Ian Glaspole4,7,8, Nicole Goh4,7,9,10, Gregory Keir4,11, Heather Allan4,12, Sally Chapman4,13, Wendy Cooper4,14,15, Samantha Ellis4,16, Peter Hopkins4,17,18, Yuben Moodley4,19, Paul Reynolds4,13, Chris Zappala4,20, Sacha Macansh4,12, Christopher Grainge1,2,3,4. 1. Respiratory Department, John Hunter Hospital (JHH), Newcastle, NSW, Australia. 2. School of Medicine, Newcastle University, Newcastle, NSW, Australia. 3. Hunter Medical Research Institute (HMRI), Newcastle, NSW, Australia. 4. Australian Idiopathic Pulmonary Fibrosis Registry (AIPFR), Brisbane, QLD, Australia. 5. Department of Respiratory Medicine, Royal Prince Alfred Hospital, Sydney, NSW, Australia. 6. Faculty of Medicine, University of Sydney, Sydney, NSW, Australia. 7. Department of Allergy and Respiratory Medicine, The Alfred Hospital, Melbourne, VIC, Australia. 8. Faculty of Medicine, Monash University, Melbourne, VIC, Australia. 9. Department of Respiratory Medicine, Austin Hospital, Melbourne, VIC, Australia. 10. Institute for Breathing and Sleep, Melbourne, VIC, Australia. 11. Department of Respiratory Medicine, Princess Alexandria Hospital, Brisbane, QLD, Australia. 12. Lung Foundation Australia, Brisbane, QLD, Australia. 13. Department of Respiratory Medicine, Royal Adelaide Hospital, Adelaide, SA, Australia. 14. Tissue pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Sydney, NSW, Australia. 15. School of Medicine, Western Sydney University, Sydney, NSW, Australia. 16. Department of Radiology, The Alfred Hospital, Melbourne, VIC, Australia. 17. School of Medicine, University of Queensland, Brisbane, QLD, Australia. 18. Queensland Lung Transplant Service, The Prince Charles Hospital, Brisbane, QLD, Australia. 19. Department of Respiratory Medicine, Fiona Stanley Hospital, Perth, WA, Australia. 20. Department of Thoracic Medicine, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia.
Abstract
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.
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.
Authors: Margaret L Salisbury; Craig S Conoscenti; Daniel A Culver; Eric Yow; Megan L Neely; Shaun Bender; Nadine Hartmann; Scott M Palmer; Thomas B Leonard Journal: Ann Am Thorac Soc Date: 2020-11