Background Forced expiratory volume in 1 s (FEV1) indicates lung health in cystic fibrosis (CF). FEV1 is commonly communicated as a per cent predicted of a healthy individual sharing the same age, sex, race and height. CF-specific reference equations are complementary and calibrate a patient’s FEV1 to that of their CF peers.
Objectives (1) To derive Canadian CF-specific FEV1 reference percentiles (FEV1%iles), (2) characterize how they have changed over time and (3) compare the Canadian FEV1%iles to those for USA and European CF populations.
Method CF FEV1%iles are calculated using the Canadian CF Registry and quantile regression.
Results The Canadian FEV1%iles demonstrated better lung function in more recent time periods within Canada, especially below the 50% percentile and in males. When compared to USA and European FEV1%iles for the same time period, Canadian FEV1%iles were higher.
Conclusion CF-specific FEV1%iles can provide useful information about changes in lung health. An online calculator (available at cfpercentile.research.sickkids.ca) makes these FEV1%iles accessible.
- cystic fibrosis
- respiratory measurement
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Contributors All authors contributed to the data analysis, manuscript preparation and revisions. All authors have approved the final version of this paper.
Funding This work was funded by grants to LJS from the Canadian Institutes of Health Research (CIHR; MOP-258916), the Natural Sciences and Engineering Research Council of Canada (NSERC; 371399-2009) and Cystic Fibrosis Canada (#2626).
Competing interests None declared.
Ethics approval Research Ethics Board of Hospital for Sick Children, Toronto, Canada.
Provenance and peer review Not commissioned; externally peer reviewed.
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