Shan Nie,1,* Ailin Yang,1,2,* Wei Yuan,1 Nan Jia,1 Yunxiao Li,1 Yue Yu,1,3 Bo Xu,1 Qiufen Xu,1 Haoyan Wang,1 Xin He1 

1Department of Respiratory Medicine, Capital Medical University Affiliated Beijing Friendship Hospital, Beijing, People’s Republic of China; 2Department of Respiratory and Critical Medicine, Sichuan Provincial People’s Hospital, University of Electronic Science and Technology of China, Chengdu, Sichuan, People’s Republic of China; 3Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Third Military Medical University (Army Medical University), Chongqing, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Haoyan Wang, Email haoyanw@ccmu.edu.cn Xin He, Email cynthia_cruise@hotmail.com

Background: Automatic dysfunction is present in patients with Chronic Obstructive Pulmonary Disease (COPD). Heart rate recovery at 1 min (HRR1) after Cardiopulmonary Exercise Testing (CPET) serves an indicator of automatic function. Despite its potential significance, this primary method is still not well understood or widely utilized in predicting the progression of COPD. This study aimed to determine whether this indicator predicts acute exacerbations of COPD (AECOPD).
Methods: In this prospective cohort study, 62 patients with COPD were recruited from 2013 to 2017. All participants underwent CPET test and followed up for 5 years thereafter. Univariate and multivariate linear regression, as well as Cox regression, were utilized to identify the abnormal HRR1 and the variables influencing AECOPD.
Results: HRR1 after CPET was a significant correlation of COPD progression. According to the Receiver Operating Characteristic curve, 14 beats/min for HRR1 was optimally used to measure the characteristics of COPD patients. HRR1≤ 14 beats/min significantly predicted the time to the first AECOPD (p=0.00032, Log rank test). In the Cox proportional hazard models, HRR1≤ 14 beats/min was also consistently correlated with AECOPD occurrence (Hazards ratio=8.30, p=0.001).
Conclusion: HRR1 after CPET was an independent predictor of AECOPD. Thus, this index can be applied to observe the conditions and treatment results of COPD patients.

Keywords: COPD, exacerbations, heart rate recovery, cardiopulmonary exercise test, autonomic dysfunction