Reliability of Pulmonary Function Tests in Patients with Chronic Obstructive Pulmonary Disease

Area of Science:

• Pulmonology
• Respiratory Medicine
• Clinical Trials

Background:

• Chronic Obstructive Pulmonary Disease (COPD) diagnosis is often delayed due to issues with spirometry use and quality.
• High-quality spirometry is essential for accurate COPD diagnosis and management.

Purpose of the Study:

• To evaluate the quality and characteristics of spirometry tests performed in COPD patients across multiple Turkish tertiary care centers.
• To identify common spirometry patterns, reference value usage, and potential quality issues in a real-world clinical setting.

Main Methods:

• A prospective observational study involving 560 spirometry tests from six centers in Turkey.
• Independent evaluation of spirometry tests by two pulmonologists, with inter-rater reliability assessed using Cohen's Kappa.
• Analysis of spirometry patterns, post-bronchodilator use, graphical data, reference values, and specific error indicators.

Main Results:

• Obstructive patterns were found in 79.1% of spirometry tests, with high inter-rater reliability (K=0.890).
• European Community for Steel and Coal (ECSC) was the predominant reference standard (86.4%).
• Low rates of inconclusive (5.5%) and erroneous tests (e.g., insufficient effort 13.4%, mouth leak 1.8%) were reported, though increased concavity (83%) and small airway obstruction (87%) were common interpreter findings.

Conclusions:

• While spirometry quality in COPD patients shows good inter-rater reliability for patterns, reports often omit essential clinical information.
• The use of ECSC as a reference is widespread, but improvements in reporting completeness are needed for better COPD diagnosis and care.
• Low rates of technically flawed tests suggest a foundation for quality improvement initiatives in spirometry for COPD.