Comparison of different reference values for lung function: implications of inconsistent use among centers.

Area of Science:

• Pulmonary Medicine
• Clinical Diagnostics
• Respiratory Physiology

Background:

• Pulmonary function tests (PFTs) require established reference values for accurate interpretation.
• Norway currently uses European Coal and Steel Community (ECSC) values, despite recommendations for the newer Global Lung Function Initiative (GLI) standards.
• This study investigates the clinical impact of transitioning from ECSC to GLI reference values.

Purpose of the Study:

• To compare the effects of using ECSC versus GLI reference values for spirometry, DLCO, and lung volumes.
• To assess the differences in percent predicted values and lower limits of normal (LLN) between the two reference sets.
• To evaluate the clinical implications of this change in a cohort of adult patients.

Main Methods:

• Utilized PFT data from 577 adults (aged 18-85, 45% female).
• Compared ECSC and GLI reference values for FVC, FEV1, DLCO, TLC, and RV.
• Calculated percent predicted values and LLN, employing Bland-Altman plots to assess agreement.

Main Results:

• GLI values showed lower FVC/FEV1 and higher DLCO/RV predictions compared to ECSC in both sexes.
• Differences were most pronounced in females: mean difference of 15 pp for DLCO and 17 pp for RV.
• GLI identified 23% of females with DLCO below LLN, versus 49% with ECSC.

Conclusions:

• The shift from ECSC to GLI reference values has significant implications for diagnosing and treating respiratory conditions.
• Discrepancies affect healthcare benefits, clinical trial eligibility, and diagnostic criteria.
• Nationwide, consistent implementation of GLI reference values is essential for equitable patient care.