Updated reference values for static lung volumes from a healthy population in Austria

Area of Science:

• Pulmonary Medicine
• Medical Statistics
• Respiratory Physiology

Background:

• Accurate lung volume reference values are crucial for diagnosing restrictive lung diseases and hyperinflation.
• Existing Global Lung Function Initiative (GLI) equations require validation in diverse populations.
• This study assessed the suitability of GLI equations in a healthy Austrian cohort.

Purpose of the Study:

• To evaluate the Global Lung Function Initiative (GLI) reference equations for static lung volumes in a representative Austrian population.
• To develop new, population-specific reference equations if the GLI equations showed inadequate performance.
• To improve the diagnosis of lung diseases in the Austrian population.

Main Methods:

• Analysis of spirometry and body plethysmography data from 5371 healthy Austrian subjects (aged 6-80 years) from the Austrian LEAD Study.
• Assessment of GLI equation fit using z-scores and normality distributions.
• Development of new Austrian reference equations using the LMS method and generalized additive models.

Main Results:

• The GLI static lung volume equations demonstrated a poor fit for the Austrian cohort, particularly for females.
• Mean z-scores exceeded established normality limits for residual volume (RV), RV/total lung capacity (TLC), TLC, expiratory reserve volume (ERV), and inspiratory capacity.
• Population-derived reference equations from the LEAD cohort showed superior fit and reproducibility for lung volumes.

Conclusions:

• The GLI lung volume reference equations are not optimal for the Austrian population, necessitating localized equations.
• A new set of Austrian reference equations for static lung volumes has been developed.
• These new equations are applicable to both children and adults aged 6-80 years, enhancing diagnostic accuracy.