Correlation of Six Minute Walking Test, Sit to Stand Test and Pulmonary Function Test in Patients with Chronic Obstructive Pulmonary Disease

ntroduction: Assessment of functional capacity in Chronic Obstructive Pulmonary Disease (COPD) patients helps in determining the severity of the disease. While spirometry is the gold standard, six Minute Walk Test (6MWT) and one minute Sit To Stand Test (STST) are simple and practical tests to assess exercise capacity and physical condition.

Aim: To find the diagnostic accuracy of these of 6MWT and one minute STST in comparison with spirometry.

Materials and Methods: This cross-sectional study was conducted in the Department of General Medicine at Sri Devaraj Urs Academy of Higher Education and Research, Kolar, Karnataka, India, from January 2019 to December 2019. All cases of COPD diagnosed using GOLD 2018 criteria were included in the study. Patients performed 6MWT and one minute STST. Heart rate, blood pressure, oxygen saturation, SpO2, dyspnoea, and fatigue (Borg scale) were noted pretest and post-test. The sensitivity, specificity, predictive values and diagnostic accuracy of the screening test with the decided cut-off values along with their 95% CI were presented. A p-value <0.05 was considered statistically significant.

Results: The mean age of the patients was 64.09±8.31,while there were 112 (94.9%) males and 6 (5.1%) female. Overall, 81.54% of the participants had severe/very severe COPD group, walked <332.49 meters, and only 18.46% could walk more than 332.50 m. The SpO2 decreased from 93.98±0.82 to 91.75±1.39. During the one minute STST, SpO2 decreased from 93.98±0.82 to 91.75±1.39. A positive correlation was observed between the one minute STST, and it had good predictive validity in predicting COPD, as compared with spirometry {Area Under the Curve (AUC) of 0.915 (95% CI 0.866 to 0.963, p-value <0.001)}. 6MWT has a sensitivity of 81.54%, the specificity of 79.25%, and one minute STST had a sensitivity of 89.23%, specificity of 67.92% in predicting COPD.

Conclusion: In a remote clinical setting, where spirometry is not available, 6MWT and one minute STST are the best methods for assessing COPD severity.