Validity of the GOLD 2017 classification in the prediction of mortality and respiratory hospitalization in patients with chronic obstructive pulmonary disease

Figures & data

Table 1 Baseline characteristics of enrolled subjects by GOLD 2017 classification

Characteristics	A (n=35)	B (n=77)	C (n=7)	D (n=30)	p-value
Age, yr	70.3±7.51	71.2±7.62	70.7±9.38	72.6±7.70	0.661
Male gender, %	100	83.1	100	80	0.033
BMI, kg/m2	23.2±2.93	21.4±2.90	23.2±2.76	20.2±3.66	0.001
Smoking status, n (%) Current smoker Former smoker	12 (34.3) 23 (65.7)	33 (42.9) 44 (57.1)	2 (28.6) 5 (71.4)	6 (20.0) 24 (80.0)	0.162
FEV1, % predicted	62.8±13.4	51.6±19.1	54.5±12.4	34.9±10.4	<0.001
DLco, % predicted (n=110)	87.6±21.7	71.3±26.8	88.1±12.1	53.9±20.6	<0.001
Residual volume, % predicted (n=116)	171.2±58.4	179.6±58.2	151.9±19.6	213.5±76.3	0.096
Number of exacerbations per one year	0.14±0.36	0.29±0.46	2.00±0.00	2.83±1.09	<0.001
6MWT	393.1±74.8	325.0±88.2	372.9±39.9	286.0±84.2	<0.001
BODE index	1.83±0.89	3.61±2.08	2.00±0.82	5.57±1.63	<0.001
Comorbid diseases, n (%) Hypertension Diabetes Cardiovascular disease	7 (20) 3 (8.6) 8 (22.9)	14 (18.2) 6 (7.8) 9 (11.7)	3 (42.9) 2 (28.6) 1 (14.3)	12 (40.0) 5 (16.7) 5 (16.7)	0.064 0.232 0.504
Respiratory hospitalization, n (%)	6 (17.1)	25 (32.5)	4 (57.1)	25 (83.3)	<0.001
Mortality, n (%)	4 (11.4)	15 (19.5)	2 (28.6)	16 (53.3)	0.001

Note: Values are presented as mean ± SD unless otherwise noted.

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; BMI, body mass index; FEV₁, forced expiratory volume in 1 second; DLco, diffusing capacity for carbon monoxide; 6MWT, 6 min walk test; BODE, body-mass index, airway obstruction, dyspnea, and exercise.

Figure 1 Distribution (%) of patients with COPD by GOLD 2017 and GOLD 2011 classifications.

Figure 2 Comparison of mortality and respiratory hospitalization between the unchanged group C/D and group A/B that was from 2011 GOLD group C/D.

Table 2 Predictive factors for respiratory hospitalization based on the univariate and multivariate* logistic regression analyses

GOLD	Respiratory hospitalization
	OR (95% CI)	Adjusted OR (95% CI) *
2007 GOLD 1	1	1
2007 GOLD 2	2.08 (0.23–18.4)	2.83 (0.31–26.1)
2007 GOLD 3	6.00 (0.67–53.4)	8.24 (0.87–78.2)
2007 GOLD 4	18.0 (1.72–188.1)	31.5 (2.52–394.4)
2011 GOLD A	1	1
2011 GOLD B	1.67 (0.50–5.52)	1.40 (0.40–4.85)
2011 GOLD C	3.57 (0.80–15.9)	3.67 (0.79–17.1)
2011 GOLD D	7.41 (2.52–21.8)	6.75 (2.07–22.0)
2017 GOLD A	1	1
2017 GOLD B	2.32 (0.86–6.32)	1.93 (0.67–5.60)
2017 GOLD C	6.44 (1.14–36.6)	7.55 (1.25–45.8)
2017 GOLD D	24.2 (6.57–88.8)	25.0 (6.01–102.9)

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; OR, odds ratio; CI, confident interval.

Note: *Multivariate models adjusted for gender, age, body mass index, and smoking history.

Table 3 p-values in the comparisons of the predictive accuracy of the BODE index and the GOLD 2007, GOLD 2011, and GOLD 2017 classifications using ROC curve analyses

	p-values for mortality	p-values for respiratory hospitalization
BODE vs GOLD 2007	0.002	0.009
BODE vs GOLD 2011	0.088	0.175
BODE vs GOLD 2017	0.979	0.765
GOLD 2007 vs GOLD 2011	0.150	0.715
GOLD 2007 vs GOLD 2017	0.013	0.308
GOLD 2011 vs GOLD 2017	0.045	0.296

Abbreviations: ROC, Receiver Operation Characteristic; BODE, BMI, Obstruction, Dyspnea, Exercise; GOLD, Global Initiative for Chronic Obstructive Lung Disease.

Figure 3 Receiver operator characteristics curves of 2007 GOLD, 2011 GOLD, 2017 GOLD, and BODE index to predict respiratory hospitalization (3-A) and mortality (3-B).

Figure 4 Kaplan-Meier curves of the overall survival according to the 2007, 2011, and 2017 GOLD classifications.