Correlation of Six-Minute Walk Test and COPD Assessment Test (CAT) Scores with Spirometric Indices in Chronic Obstructive Pulmonary Disease Patients

Abstract

Background: For chronic obstructive pulmonary disease spirometry assessment of post-bronchodilator FEV1 is critical for establishing the diagnosis, staging of the disease, predicting the outcome, and planning treatment. The six-minute walk test (6MWT) is an endurance test used to evaluate functional status of patients with cardiopulmonary disorders. CAT score is a well-established tool for determining the impact of COPD on one's health. Objective: To find out correlation between spirometric indices FEV1, FVC, FEV1/FVC, 6MWT and CAT Scores in COPD patients. Design: Cross sectional study Setting: Conducted from September 2019 to September 2021, for a period of 24 months in a tertiary care hospital in India Materials and Methods: In this study, the correlation between spirometric indices FEV1, FVC, FEV1/FVC, 6MWT and CAT Scores was analyzed in 100 patients diagnosed with COPD. Main outcome measures: 6MWT, CAT Scores and Spirometry values in COPD Sample size: 100 Results: Most patients were males(75%) between the ages of 61-70(36%). Majority were in Stage 3 COPD(55%), followed by stage 2 of GOLD staging(25%). Most of them had CAT score range of 21–30(51%), followed by 10–20(48%) and on 6MWT majority walked a distance of 301-400 meters(43%), followed by > 400 meters(35%). The pulse rate and mean systolic blood pressure increased while mean SpO2 decreased post-6WMT with a statistically significant difference(P<.001). The correlation of 6MWT and spirometry parameters shows there was a strong positive correlation of FEV1, FVC, and FEV1/FVC with 6MWT and correlation of CAT score and spirometry parameters shows there was a strong positive correlation of FEV1, FVC, and FEV1/FVC with 6MWT with a statistically significant difference (P<.0001). There was a strong negative correlation between 6MWT and CAT score with a statistically significant difference (P<.0001) Conclusion: The 6MWT and CAT score can be used as an effective alternative to determine the severity of COPD, according to the findings of this study especially in rural settings where access to spirometry is limited. Limitations: Majority of the individuals in our study had mild–moderate COPD severity, emphasizing that the 6MWT's validity and efficacy should be assessed in all COPD grades. Conflict of interest: None