Prediction of severe exacerbations and mortality in COPD: the role of exacerbation history and inspiratory capacity/total lung capacity ratio

Figures & data

Table 1 Baseline characteristics by GOLD 2011 group

Parameter	A (n=16)	B (n=21)	C (n=13)	D (n=48)
Age (years)	63.0 (49.0–80.0)	65.0 (49.0–80.0)	70.0 (49.0–74.0)	67.0 (44.0–80.0)
Female, n (%)	1 (6.2)	7 (33.3)	1 (7.7)	6 (12.5)
IC (%)	110.5 (76.0–143.0)a,c	106.0 (47.0–161.0)b	96.0 (51.0–115.0)c	72.0 (31.0–141.0)
FEV1/FVC	65.9 (36.0–79.9)a	56.5 (38.1–79.6)b	38.5 (27.5–69.9)	35.1 (23.1–63.9)
TLC (%)	110.0 (75.0–135.0)	108.0 (63.0–157.0)c	126.0 (95.0–141.0)c	123.0 (61.0–184.0)
ITGV (%)	109.5 (74.0–167.0)a	114.0 (78.0–187.0)b	173.0 (100.0–189.0)	164.0 (73.0–294.0)
RV (%)	110.5 (42.0–158.0)a	121.0 (70.0–191.0)b	183.0 (121.0–216.0)	197.5 (65.0–437.0)

Notes: All measures taken postbronchodilation. All values, except gender, presented as median (minimum–maximum). The predicted values used for lung function are the ECSC/ERS equations.³⁶ GOLD 2011 groups defined in the “Data collection and follow-up” section.

a P<0.001 A vs C/D;

b P<0.001 B vs C/D;

c P=0.005.

Abbreviations: ECSC, European Community for Steel and Coal; GOLD, Global Initiative for Chronic Obstructive Lung Disease; IC, inspiratory capacity; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; TLC, total lung capacity; ITGV, intrathoracic gas volume; RV, residual volume.

Figure 1 Baseline FEV₁ between GOLD groups.

Notes: *P<0.01; **P<0.001. GOLD 2011 groups defined in the “Data collection and follow-up” section.

Abbreviations: FEV₁, forced expiratory volume in 1 s; GOLD, Global Initiative for Chronic Obstructive Lung Disease.

Figure 2 Baseline mMRC between GOLD groups.

Notes: *P<0.01; **P<0.001. GOLD 2011 groups defined in the “Data collection and follow-up” section.

Abbreviations: mMRC, modified Medical Research Council; GOLD, Global Initiative for Chronic Obstructive Lung Disease.

Figure 3 Exacerbations in the previous year between GOLD groups.

Notes: *P<0.01; **P<0.001. GOLD 2011 groups defined in the “Data collection and follow-up” section.

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

Figure 4 Baseline IC/TLC between GOLD groups.

Notes: *P<0.001. GOLD 2011 groups defined in the “Data collection and follow-up” section.
Abbreviations: IC/TLC, inspiratory capacity/total lung capacity; GOLD, Global Initiative for Chronic Obstructive Lung Disease.

Table 2 Comparison of variables at baseline and outcomes at 5 years by GOLD 2011 group

Parameter	A (n=16)	B (n=21)	C (n=13)	D (n=48)
Ex previous year	0 (0.0)a,b	9 (42.9)c,d	12 (92.3)	42 (87.5)c,d
IC/TLC<25%	0 (0.0)e	1 (4.8)d	6 (46.2)	19 (39.6)d,e
D or A after 5 years	3 (18.8)a	6 (28.6)d	8 (61.5)	35 (72.9)d
Ex after 5 years	9 (56.2)b	5 (23.8)c	9 (69.2)	43 (89.6)c

Notes: IC/TLC measures taken post-bronchodilation. All values presented as n (%). GOLD 2011 groups defined in the “Data collection and follow-up” section.

a P<0.001 A vs C/D;

b P<0.01 A vs B/D;

c P<0.001;

d P<0.01;

e P<0.01.

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; Ex, exacerbations; IC/TLC, inspiratory capacity/total lung capacity; D or A, death or admission.

Table 3 Predictors of death or readmission after 5 years and of exacerbations after 5 years on multivariate analyses

Subgroup/predictor(s)	Death or readmission after 5 years				Exacerbations after 5 years
	B	Exp (B)	95% CI for Exp (B)	P-value	B	Exp (B)	95% CI for Exp (B)	P-value
GOLD D 2011 Group
Age (years)	0.122	1.130	0.998–1.279	0.054	0.125	1.133	0.858–1.495	0.379
FEV1 (%)	−0.215	0.807	0.680–0.957	0.014	0.042	1.043	0.764–1.422	0.793
Exacerbations in previous year (n)	1.860	6.423	0.978–42.179	0.053	4.232	68.855	17.364–273.039	<0.001
Total population
Age (years)	0.052	1.053	0.992–1.118	0.090	0.003	1.003	0.863–1.165	0.973
IC/TLC (%)	−10.465	0.000	0.000–0.023	0.002	11.203	7.3×10^4	2.4×10^−5–2.3×10^14	0.315
Exacerbations in previous year (n)	0.817	2.263	1.189–4.306	0.013	4.010	55.120	19.216–158.103	<0.001

Note: GOLD D 2011 group defined in the “Data collection and follow-up” section.

Abbreviations: GOLD, Global Initiative for Chronic Obstructive Lung Disease; FEV₁, forced expiratory volume in 1 s; IC/TLC, inspiratory capacity/total lung capacity; B, unstandardized coefficient; 95% CI, 95% confidence interval for Exp (B).

QuanjerPHTammelingGJCotesJEPedersenOFPeslinRYernaultJCLung volumes and forced ventilatory flows. Report Working Party Standardization of Lung Function Tests, European Community for Steel and Coal. Official Statement of the European Respiratory SocietyEur Respir J Suppl19936Suppl 16540

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