ABSTRACT
Background: Despite limited validation data (Kalin et al Systematic Reviews 2021 Mar 16;10(1):77), the 1MSTS was widely used as a rapid exercise test to assess exertional oxygen desaturation during the COVID-19 pandemic. Aim(s): To assess the diagnostic accuracy of the 1MSTS to detect significant exertional oxygen desaturation in people with chronic respiratory disease. Method(s): 99 patients referred for pulmonary rehabilitation assessment were assessed for ambulatory oxygen requirements using a shuttle walk test according to British Thoracic Society Guidelines for Home Oxygen Use. Exertional oxygen desaturation was defined as a drop in oxygen saturations (SpO ) of >=4% with nadir <90%. 1MSTS was conducted in each participant by an assessor blinded to ambulatory oxygen assessment results. Result(s): Mean(SD) age 68.9(11.4) years, 59%COPD, 13%ILD. 21% demonstrated significant exertional oxygen desaturation. Using a drop of SpO >=4% to nadir <90% threshold, the 1MSTS only identified 6 out of 21 patients with exertional oxygen desaturation (sensitivity 29%). Simplifying the threshold to a drop in SpO of >=4% alone during 1MSTS improved sensitivity to 81% with specificity of 87%. Conclusion(s): Using a threshold of drop in SpO of >=4%, the 1MSTS test had reasonable sensitivity and specificity identifying significant exertional oxygen desaturation in patients with chronic respiratory disease.