Reference Values for Spirometry Derived Using Lambda, Mu, Sigma (LMS) Method in Korean Adults: in Comparison with...

Area of Science:

• Pulmonary Medicine
• Biostatistics
• Public Health

Background:

• Existing spirometry prediction equations require updates to accurately reflect current population data.
• The lambda, mu, sigma (LMS) method offers a robust approach for modeling complex data distributions in reference values.

Purpose of the Study:

• To update spirometry prediction equations and their lower limits of normal (LLN) using the LMS method.
• To compare newly derived spirometric reference values with previously established equations.

Main Methods:

• Utilized spirometric data from 10,249 healthy non-smokers in the KNHANES IV and V surveys.
• Applied the LMS method to model skewness (lambda), mean (mu), and coefficient of variation (sigma) for deriving new reference equations.
• Compared the generated equations against prior spirometric reference values.

Main Results:

• Developed new prediction equations for spirometry in the form: predicted value = e{a + b × ln(height) + c × ln(age) + M - spline}.
• The LMS-derived equations demonstrated improved accuracy in reflecting pulmonary function transitions in young adults compared to 2013 conventional regression equations.
• Observed partial discrepancies between the new reference values and those from the Global Lung Function Initiative (2012).

Conclusions:

• New spirometry reference values and LLN derived via the LMS method offer enhanced accuracy for young adults.
• Interpretation of LLN for forced expiratory volume in one second/forced vital capacity in elderly males requires caution.
• Emphasizes serial spirometry and clinical correlation for pulmonary function assessment, with a need for future studies to refine continuous reference values.