From: Determinants of chronic obstructive pulmonary disease severity in the late-elderly differ from those in younger patients
Prevalence (%)
p value
<75 years old
≥75 years old
I
1/52 (1.9 %)
3/41 (7.3 %)
n.s.
II
4/114 (3.5 %)
13/88 (14.8 %)
0.0043
III
7/67 (10.4 %)
11/48 (22.9 %)
IV
14/19 (73.7 %)
2/14 (14.3 %)
0.002