Predictive Value of the Oxygen Desaturation Induced by the 30-second Sit-to-stand-test combined with COPD Patient Self-assessment Test in Exercise-induced Hypoxemia and Its Clinical Application postprint

Abstract: Background　Chronic obstructive pulmonary disease（COPD） is one of the most common respiratory diseases in elderly patients，and a decrease in oxygen saturation during activity is a common phenomenon correlated with the prognosis. Current assessment of exercise-induced hypoxia（EID） has yielded controversial results. Objective　To explore methods suitable for inducing EID in community and home-based COPD patients. Methods　This was a retrospective study involving 76 patients with stable COPD admitted to China-Japan Friendship Hospital from January 2021 to August 2023. Resting oxygen saturation and the lowest oxygen saturation during exercise（ΔSpO2） in the six-minute walk test 6MWT） were recorded. Based on the criterion of ΔSpO2 ≥ 4% for the diagnosis of EID，patients were assigned into non-EID group and EID group. Pulmonary function indicators，ΔSpO2 during 30-second sit-to-stand-test（30s STST），and COPD Assessment Test （CAT） were compared between the two groups. The correlation of ΔSpO2 in 6MWT with ΔSpO2 of 30s STST and CAT scores was identified. The predictive value of ΔSpO2 of 30s STST，CAT score，andΔSpO2 of 30s STST combined with CAT score in predicting EID was analyzed using the receiver operating characteristic（ROC） curves. Results　There were significant differences in the ΔSpO2 of 30s STST and CAT score between non-EID group and EID group. The cut-off value of ΔSpO2 of 30s STST in predicting EID was 2，with the sensitivity，specificity and area under the curve（AUC） of 59.6%，82.8%， 0.730（95%CI=0.614-0.846，P<0.05），respectively. The cut-off value of CAT scores in predicting EID was 13，with the sensitivity，specificity and AUC of 48.9%，79.3%，0.712（95%CI=0.596-0.828，P<0.05），respectively. The cut-off value of ΔSpO2 of 30s STST combined with CAT scores in predicting EID was 0.593，with the sensitivity，specificity and AUC of 70.2%，72.4% and 0.765 （95%CI 0.659-0.871，P<0.001），respectively. Conclusion　ΔSpO2 of 30s STST ≥ 2% and CAT score ≥ 13 points alarm the development of EID. The 30s STST and CAT can be used as community and home-based measures to predict the induction of EID in patients with stable COPD.