Development of a spirometry T-score in the general population

Area of Science:

• Pulmonary Medicine
• Biostatistics
• Epidemiology

Background:

• Spirometry measures lung function, crucial for diagnosing and monitoring respiratory diseases.
• Standardizing spirometry results using T-scores, analogous to bone density T-scores, can improve clinical interpretation.
• Developing a spirometry T-score offers a novel way to assess lung function relative to a healthy reference population.

Purpose of the Study:

• To develop and validate a spirometry T-score for assessing lung function.
• To evaluate the predictive value of the spirometry T-score for mortality and healthcare utilization.

Main Methods:

• T-scores were derived from lambda-mu-sigma (LMS) Z-scores using a young, normal reference population.
• All-cause death, respiratory death, and COPD death were assessed in 9,101 US subjects over 10 years.
• COPD-related healthcare utilization was evaluated in 1,894 Korean subjects over 4 years.

Main Results:

• A steep increase in all-cause death probability was observed when forced expiratory volume in 1 second (FEV1) T-scores fell below -2.5.
• Survival curves for mortality and COPD utilization differed significantly across FEV1 T-score strata (P<0.001).
• Adjusted hazard ratios indicated that lower FEV1 T-scores significantly predicted increased risk for all-cause death, respiratory death, COPD death, and COPD utilization.

Conclusions:

• The spirometry T-score is a valuable tool for predicting adverse respiratory outcomes.
• This T-score can identify individuals at higher risk for mortality and COPD-related healthcare utilization.
• The spirometry T-score offers a standardized and clinically relevant measure of lung function impairment.