Validation of the GOLD 2017 and new 16 subgroups (1A–4D) classifications in predicting exacerbation and mortality in COPD patients

Figures & data

Table 1 Characteristics of 553 patients according to the GOLD 2017 classification

GOLD 2017	Group A, N=157	Group B, N=186	Group C, N=38	Group D, N=172	P-value
Males, %	93.0	93.0	94.7	94.8	0.878
Age, years	67.55 (11.23)	72.37 (9.66)	68.84 (10.77)	72.94 (9.60)	<0.001
BMI, kg/m^2	23.82 (3.89)	23.27 (4.31)	23.32 (4.79)	22.64 (4.22)	0.09
mMRC score	0.83 (0.42)	2.30 (0.54)	0.79 (0.41)	2.64 (0.70)	<0.001
FEV1 % pred	75.29 (19.04)	63.54 (24.04)	66.13 (19.31)	51.63 (19.95)	<0.001
Charlson index	2.01 (1.45)	2.09 (1.45)	2.50 (1.77)	2.67 (1.72)	<0.001
Current smoker, %	54.1	59.6	56.8	69.0	0.047
Smoking/pack-years	46.79 (36.92)	51.96 (38.76)	53.38 (49.47)	54.34 (41.76)	0.425
Major CV diseases, %	20.4	23.7	23.7	37.2	0.003
Inhaled therapy
LABA + ICS, %	27.4	37.5	36.8	40.1	0.085
LAMA, %	36.3	39.1	39.5	37.8	0.955
Triple therapy, %	4.5	7.3	13.9	11.3	0.084

Note: Data are presented as the mean (SD), unless otherwise stated.

Abbreviations: CV disease, cardiovascular disease (including old myocardial infarction, coronary artery disease, and congestive heart failure); FEV₁ % pred, forced expiratory volume in 1 second % predicted; GOLD, Global Initiative for Chronic Obstructive Lung Disease; LABA + ICS, long-acting beta2 agonists and inhaled steroid; LAMA, long-acting muscarine antagonist; mMRC, modified Medical Research Council; Triple therapy, combined inhaled steroids, long-acting beta2 agonists, and long-acting muscarine antagonist.

Table 2 Prognosis for patients according to the GOLD 2017 classificationa

GOLD 2017	Group A, N=157	Group B, N=186	Group C, N=38	Group D, N=172	P-value
Average number of exacerbation/years
Total exacerbationsb	0.32 (0.83)	0.51 (1.22)	1.59 (2.37)	2.54 (3.50)	<0.001
Severe exacerbations	0.13 (0.47)	0.20 (0.58)	0.16 (0.45)	1.09 (1.91)	<0.001
Mortality, n (%)
All-cause	41 (26.1)	87 (46.8)	12 (31.6)	129 (75.0)	<0.001
Respiratory cause	7 (4.5)	47 (25.3)	7 (18.4)	81 (47.1)	<0.001
Cardiovascular cause	10 (6.4)	7 (3.8)	2 (5.3)	19 (11.0)	0.052
Cancer cause	13 (8.3)	17 (9.1)	1 (2.6)	15 (8.7)	0.503

Notes: Data are presented as the mean (SD), unless otherwise stated.

a In total, 553 patients were analyzed for mortality, and 408 patients were analyzed for exacerbation and hospitalization, where both analyses were adjusted for age.

b Total exacerbations are exacerbations including moderate (exacerbations requiring medical intervention with steroid or antibiotics) and severe exacerbations (exacerbations requiring hospitalization).

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

Table 3 Exacerbations according to the GOLD 2017 and GOLD 2013 classifications and logistic regression analyses with receiver operating curve estimations

GOLD classification	Total exacerbations		Severe exacerbations
	OR	P-value	OR	P-value
GOLD 2017
Group A	1		1
Group B	1.68 (0.91–3.11)	0.100	1.59 (0.75–3.40)	0.228
Group C	10.34 (4.25–25.17)	<0.001	6.61 (2.64–16.58)	<0.001
Group D	17.76 (9.34–33.76)	<0.001	17.61 (8.72–35.54)	<0.001
AUC	0.79 (0.74–0.83)		0.79 (0.74–0.84)
GOLD 2013
Group A	1		1
Group B	1.72 (0.83–3.55)	0.142	1.68 (0.65–4.30)	0.282
Group C	9.90 (4.34–66.21)	<0.001	8.55 (3.33–21.94)	<0.001
Group D	13.49 (7.11–25.60)	<0.001	16.52 (7.54–36.22)	<0.001
AUC	0.77 (0.72–0.82)		0.78 (0.73–0.82)

Notes: Data presented as OR (95% CI) and AUC. No difference in AUC between GOLD 2017 and 2013 were found.

Abbreviations: AUC, area under curve; GOLD, Global Initiative for Chronic Obstructive Lung Disease.

Figure 1 Distribution of patients in the GOLD 2013, 2017 classifications, and spirometric grade classifications.

Note: Data are presented as the number (%) of patients.
Abbreviation: GOLD, Global Initiative for Chronic Obstructive Lung Disease.

Table 4 Mortality according to the GOLD 2017 and GOLD 2013 classifications and spirometric grades and logistic regression analyses with ROC estimations

Classification	All-cause mortality		Respiratory cause mortality
	OR	P-value	OR	P-value
GOLD 2017
Group A	1		1
Group B	2.49 (1.57–3.93)	<0.001	7.25 (3.17–16.66)	<0.001
Group C	1.31 (0.60–2.82)	0.498	4.84 (1.58–14.78)	0.006
Group D	8.49 (5.17–13.94)	<0.001	19.07 (8.44–43.09)	<0.001
AUC	0.70 (0.66–0.74)		0.73 (0.69–0.78)
GOLD 2013
Group A	1		1
Group B	2.25 (1.34–3.78)	0.002	8.43 (2.85–24.98)	<0.001
Group C	1.63 (0.82–3.25)	0.161	8.27 (2.47–27.74)	0.001
Group D	7.35 (4.57–11.82)	<0.001	28.18 (10.09–78.74)	<0.001
AUC	0.70 (0.66–0.75)		0.74 (0.70–0.79)
Spirometric grades
Grade 1	1		1
Grade 2	1.99 (1.29–3.06)	0.002	3.56 (1.83–6.91)	<0.001
Grade 3	4.27 (2.60–7.00)	<0.001	8.12 (4.10–16.08)	<0.001
Grade 4	9.54 (3.90–23.36)	<0.001	6.73 (3.43–39.65)	<0.001
AUC	0.66 (0.62–0.71)		0.71 (0.66–0.76)

Note: Data presented as OR (95% CI) and AUC.

Abbreviations: AUC, area under curve; GOLD, Global Initiative for Chronic Obstructive Lung Disease; ROC, receiver operating characteristic.

Figure 2 Kaplan–Meier survival curves according to the GOLD 2017 classification groups A–D (A) and the 2013 classification groups A–D (B).

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

Figure 3 Kaplan–Meier survival curves according to the spirometric grades 1–4 (A), subgroup 1B–4B (B), and subgroup 1D–4D (C).

Table 5 Mortality for patients within subgroup 1A–4D according to the GOLD 2017 classificationa

GOLD 2017	All-cause	Respiratory cause	Cardiovascular cause	Cancer cause
Subgroup 1A	18 (24.3)	0 (0)	6 (8.1)	8 (7.2)
Subgroup 2A	17 (24.6)	4 (5.8)	2 (2.9)	5 (10.8)
Subgroup 3A	5 (41.7)	2 (16.7)	2 (16.7)	0 (0)
Subgroup 4A	1 (50.0)	1 (50.0)	0 (0)	0 (0)
P-value	0.41	0.002	0.26	0.58
Subgroup 1B	13 (27.7)	6 (12.8)	1 (2.1)	4 (8.5)
Subgroup 2B	41 (50.6)	19 (23.5)	6 (7.4)	5 (6.2)
Subgroup 3B	24 (53.3)	15 (33.3)	0 (0)	6 (13.3)
Subgroup 4B	9 (69.2)	7 (53.8)	0 (0)	2 (15.4)
P-value	0.01	0.01	0.13	0.49
Subgroup 1C	4 (36.4)	1 (9.1)	1 (9.1)	1 (9.1)
Subgroup 2C	5 (29.4)	3 (17.6)	1 (5.9)	0 (0)
Subgroup 3C	3 (30.0)	3 (30.0)	0 (0)	0 (0)
Subgroup 4C	0	0	0	0
P-value	1.00	0.50	0.64	0.28
Subgroup 1D	11 (55.0)	5 (25.0)	3 (15.0)	3 (15.0)
Subgroup 2D	44 (68.8)	28 (43.8)	7 (10.9)	6 (9.4)
Subgroup 3D	55 (82.1)	35 (52.2)	8 (11.9)	4 (6.0)
Subgroup 4D	19 (90.5)	13 (61.9)	1 (4.8)	2 (9.5)
P-value	0.02	0.08	0.75	0.64

Notes: Data are presented as the number (percent).

a In total, 553 patients were analyzed for mortality. Seventy-four patients in subgroup 1A, 69 patients in subgroup 2A, 12 patients in subgroup 3A, and 2 patients in subgroup 4A; 47 patients in subgroup 1B, 81 patients in subgroup 2B, 45 patients in subgroup 3B, and 13 patients in subgroup 4B; 11 patients in subgroup 1C, 17 patients in subgroup 2C, 10 patients in subgroup 3C, and 0 patients in subgroup 4C; 20 patients in subgroup 1D, 64 patients in subgroup 2D, 67 patients in subgroup 3D, and 21 patients in subgroup 4D. The statistical power for subgroups 1B–4B and 1D–4D was >0.7, but the statistical power for subgroups 1A–4A and 1C–4C was <0.7 due to the small sample size.

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