Effects of Change in 6-Minute Walking Distance on Hospital Clinical Events in Patients with Pulmonary Arterial Hypertension: A Retrospective Cohort Study

Purpose:The aim of this study was to confirm the correlation between different change rates of 6-minute walking distance (6MWD) and unplanned hospital readmission (HR) and frequency of emergency department (ED) visits in patients with pulmonary arterial hypertension (PAH).Methods: A total of 215 individuals diagnosed with PAH were enrolled in this study and finally, 139 patients divided into three groups according to change rate of 6-Minute Walk Test (6MWT); group 1 (15%, n=54), group 2 (0% and 15%, n=47), and group 3 (0%, n=38).The primary outcomes were unplanned HR, ED visits, and hospital visits, which were compared between the three groups.Results: A significant difference in unplanned HR was observed between the three groups (p=0.011), and in the post-hoc test, group 1 had a higher frequency of unplanned HR than group 2 (p=0.026).In addition, a significant difference in the hospital visits between the three groups (p=0.002).Unplanned HR (r=0.219,p=0.010) and hospital visits (r=0.359,p0.001) were positively associated with the improvement of the change rate in 6MWD.A weak negative correlation was observed between the ED visit and the improvement of change rate in 6MWD (r=-0.253,p=0.003).Conclusion: This study showed that the higher change rate in 6MWD may relate to the reduction in the frequency of ED visits in patients with PAH.