Utility of the Fifteen Steps Climbing Exercise Oximetry Test in Assessing Disease Severity in Stable COPD Patients- A Cross Sectional Study

Abstract

Background: Forced Expiratory Volume in the first second (FEV1) from spirometry is essential in diagnosing and managing COPD. Early detection of severe COPD in primary care is vital for timely referral and treatment. Spirometry is often underutilized in rural areas due to limited resources. The Fifteen Steps Climbing Exercise Oximetry Test (15SCT) offers an alternative for assessing COPD severity. Objective: To evaluate the efficacy of 15SCT in determining disease severity in stable COPD patients. Methods: This cross-sectional study was conducted at the National Institute of Diseases of the Chest and Hospital (NIDCH) from June 2022 to August 2023, involving 116 stable COPD patients. Spirometry confirmed COPD diagnosis and severity grading. Pulse, respiratory rate, and oxygen saturation (SpO2) were measured pre- and post-15SCT. Data were analyzed using SPSS v.23, employing Paired t-test, Unpaired t-test, and ROC curve analysis. Results: Patients (mean age 61.3±8.1 years; M:F = 22.2:1) showed moderate (50.0%), severe (43.1%), very severe (5.2%) and mild (1.7%) COPD. Most patients (52.6%) took 61-90 seconds for 15SCT. Post-15SCT SpO2 significantly decreased from baseline (92.9±2.3% vs. 96.3±1.3%; p<0.05). Patients with FEV1<50% had higher SpO2 reduction (4.37±1.12%) than those with FEV1 ³50% (2.51±0.96%). ROC analysis identified a ³3.5% SpO2 drop as indicative of severe airflow limitation with good sensitivity (80.4%), specificity (90.0%) positive predictive value (88.2%), and negative predictive value (83.1%). Conclusion: Significant exercise-induced desaturation correlated with COPD severity, supporting 15SCT as a useful tool for predicting severe airflow limitation in stable COPD patients. Chest Heart J. 2024; 48(1) : 12-18