Table 6.

Number of deaths, time at risk, and crude incidence-mortality rates according to COPD classification (GOLD 2007², 2013⁶, and 2017¹ criteria)

COPD severity	Number of deaths	Total time at risk (years)	Mortality rate (per 1,000 person-year)	P-value
GOLD 2007				<0.001
I	54	1,540.98	35.0
II	35	788.93	44.4
III	13	123.18	105.5
IV	4	25.90	154.4
GOLD 2013				<0.001
A	66	1,735.18	38.04
B	16	492.90	32.46
C	14	119.27	117.38
D	10	131.65	75.96
GOLD 2017				<0.001
I-A	40	1,155.42	34.62
I-B	10	349.01	28.65
I-C	1	18.04	55.43
I-D	3	18.51	162.12
II-A	22	455.28	49.31
II-B	11	279.87	39.30
II-C	1	19.95	50.13
II-D	1	33.84	29.55
III-A	6	52.27	114.79
III-B	4	48.09	83.18
III-C	1	0.00	–
III-D	2	22.82	87.66
IV-A	1	1.03	966.27
IV-B	1	11.42	87.58
IV-C	1	9.82	101.80
IV-D	1	3.63	275.66

Note: P-values were obtained using the log rank test.

Abbreviation: GOLD, Global Initiative for Chronic Obstructive Lung Disease.