Prognostic utility of the 2011 GOLD classification and other multidimensional tools in Asian COPD patients: a prospective cohort study

Figures & data

Table 1 Baseline characteristics of the study population

Baseline characteristics	GOLD A	GOLD B	GOLD C	GOLD D	P-value
Number of subjects	188	162	256	504
Sex (%)
Male	90.4	85.2	93.0	87.3	0.041
Female	9.6	14.8	7.0	12.7
Race (%)
Chinese	80.3	85.8	73.4	75.6	0.1
Malay	14.9	8.0	18.8	18.5
Indian	3.7	4.3	6.6	5.0
Others	1.1	1.9	1.2	1.0
Age at entry	70.0±9.4a	75.5±9.1b	68.5±8.9	72.7±9.5	<0.001
Height (m)	1.62±0.08	1.60±0.08c	1.62±0.07	1.61±0.07	0.002
Weight (kg)	60.4±12.4	57.4±11.9	56.0±12.0d	54.0±12.3e	<0.001
BMI (kg/m^2)	23.0±4.4	22.8±5.4f	21.4±4.3	20.9±4.7g	<0.001
FEV1 (%)	64.3±11.4	61.9±10.9	41.4±11.8h	38.2±11.1i	<0.001
FEV1/FVC	56.3±7.7	55.9±8.2	47.4±10.5	45.9±10.9	<0.001
SGRQ score	23.2±11.1	34.5±16.2j	27.8±14.1	40.5±17.8k	<0.001

Notes:

a Lower age vs GOLD B (P<0.001) and GOLD D (P=0.004).

b Older age vs GOLD C (P<0.001) and GOLD D (P<0.001).

c Shorter vs GOLD A (P=0.019) and GOLD C (P=0.003).

d Lighter vs GOLD A (P=0.001).

e Lighter vs GOLD A (P<0.001) and GOLD B (P=0.014).

F Higher BMI vs GOLD C (P=0.016) and GOLD D (P<0.001).

g Lower BMI vs GOLD A (P<0.001) and GOLD B (P<0.001).

h Lower FEV₁ (%) vs GOLD A (P<0.001) and GOLD B (P<0.001).

i Lower FEV₁ (%) vs GOLD A (P<0.001), GOLD B (P<0.001), and GOLD C (P=0.001).

j Worse SGRQ score vs GOLD C (P<0.001).

k Worse SGRQ score vs GOLD A (P<0.001), GOLD B (P<0.001), and GOLD C (P<0.001).

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; BMI, body mass index; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; SGRQ, St. George’s Respiratory Questionnaire.

Figure 1 Adjusted Kaplan–Meier curves for exacerbation for GOLD 2011 (A), GOLD 2007 (B), mMRC quartiles (C), SGRQ quartiles (D), and BOD quartiles (E).

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; mMRC, modified Medical Research Council; SGRQ, St. George’s Respiratory Questionnaire; BOD, Body mass index, Obstruction, Dyspnea.

Figure 2 Adjusted Kaplan–Meier curves for mortality for GOLD 2011 (A), GOLD 2007 (B), mMRC quartiles (C), SGRQ quartiles (D), and BOD quartiles (E).

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; mMRC, modified Medical Research Council; SGRQ, St. George’s Respiratory Questionnaire; BOD, Body mass index, Obstruction, Dyspnea.

Figure 3 ROC curves for the five classification systems (GOLD 2011, GOLD 2007, mMRC, SGRQ, and BOD) for exacerbation (AUCs were 0.62±0.02, 0.59±0.02, 0.61±0.02, 0.60±0.02, and 0.61±0.02, respectively; (A)) and mortality (AUCs were 0.71±0.02, 0.70±0.02, 0.71±0.02, 0.71±0.02, and 0.72±0.02, respectively; (B)), with no significant difference demonstrated in the predictive abilities of all five systems (P>0.05).

Abbreviations: ROC, receiver operating characteristic; GOLD, Global Initiative for Chronic Obstructive Lung Disease; mMRC, modified Medical Research Council; SGRQ, St. George’s Respiratory Questionnaire; BOD, Body mass index, Obstruction, Dyspnea; AUCs, areas under the ROC curve.