ACE and chronic obstructive pulmonary disease: Regarding medications, the number of patients using nifedipine and spironolactone in the OS group was significantly higher than that in the other two groups (P < 0.01), and the number of patients using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and beta-blockers in the OS group was significantly higher than that in the COPD-alone group (P < 0.01).