Table 7.

Associations between GOLD classifications and prospective total moderate-to-severe annual exacerbation rate

GOLD classification	Univariate analysis		Multivariate analysisa
	IRR (95% CI)	P-value	IRR (95% CI)	P-value
GOLD 2007
Stage I	Reference		Reference
Stage II	2.3 (1.3–4.1)	0.0069	2.0 (1.0–3.8)	0.036
Stage III	2.9 (1.6–5.4)	<0.001	2.3 (1.2–4.6)	0.014
Stage IV	3.8 (1.8–7.9)	<0.001	3.2 (1.4–7.3)	0.006
GOLD 2013
Group (A)	Reference		Reference
Group (B)	2.8 (1.7–4.4)	<0.001	3.1 (1.8–5.2)	<0.001
Group (C)	2.3 (1.3–4.3)	0.008	2.0 (1.0–4.2)	0.052
Group (D)	4.6 (2.9–7.2)	<0.001	5.1 (3.0–8.4)	<0.001
GOLD 2017
Group (A)	Reference		Reference
Group (B)	2.5 (1.6–3.4)	<0.001	2.4 (1.6–3.5)	<0.001
Group (C)	2.3 (1.0–5.3)	0.060	1.0 (0.3–3.6)	0.997
Group (D)	5.1 (3.3–7.9)	<0.001	5.3 (3.3–8.6)	<0.001
Reclassified GOLD 2017 with combined group
Group (A)	Reference		Reference
Group (B)	2.3 (1.6–3.4)	<0.001	2.5 (1.6–3.7)	<0.001
Group (C+D)	4.7 (3.1–7.2)	<0.001	4.8 (3.0–7.7)	<0.001

Note:

^aAdjusted for age, sex, body mass index, and pack-years.

Abbreviation: IRR, incidence rate ratio.