Frequency of Multi-dimensional COPD Indices and Relation 
with Disease Activity Markers

Figures & data

Table 1.  General characteristics of COPD patients, by GOLD airflow limitation

	Mild (n = 218)	Moderate (n = 148)	Severe (n = 20)	Total (n = 386)	p
Males, n (%)	145 (66.5%)	110 (74.3%)	17 (85.0%)	272 (70.5%)	0.094
Age, yrs	63 ± 10	65 ± 10	70 ± 7	64 ± 10	0.005
BMI, Kg/m2	27.4 ± 4.6	28.8 ± 4.7	28.4 ± 6.3	28.0 ± 4.8	0.022
Smoking status	0.064
Current smoker, n (%)	75 (34.4%)	53 (35.8%)	4 (20.0%)	132 (34.2%)
Former smoker, n (%)	78 (35.8%)	63 (42.6%)	13 (65.0%)	154 (39.9%)
Never smoker, n (%)	65 (29.8%)	32 (21.6%)	3 (15.0%)	100 (25.9%)
Smoking exposure, packs x year	36 ± 21	49 ± 30	42 ± 30	42 ± 26	0.000
Self-reported exposure to vapours, gases, dusts or fumes, n (%)	80 (36.7%)	56 (37.8%)	11 (55.0%)	147 (38.1%)	0.271
Occupational exposure
Biological dusts, n (%)	48 (22.0%)	39 (26.4%)	8 (40.0%)	95 (24.6%)	0.167
Mineral dusts, n (%)	53 (24.3%)	40 (27.0%)	7 (35.0%)	100 (25.9%)	0.536
Gases or fumes	33 (15.1%)	41 (27.7%)	6 (30.0%)	80 (20.7%)	0.008
Active worker, n (%)	61 (28.0%)	32 (21.8%)	1 (5.0%)	94 (24.4%)	0.046
Educational level	0.417
Less than primary school, n (%)	33 (15.2%)	25 (16.9%)	5 (25.0%)	63 (16.4%)
Primary school, n (%)	80 (36.9%)	65 (43.9%)	7 (35.0%)	152 (39.5%)
Secondary school, n (%)	52 (24.0%)	37 (25.0%)	6 (30.0%)	95 (24.7%)
University degree, n (%)	48 (22.1%)	20 (13.5%)	2 (10.0%)	70 (18.2%)
Charlson index	0.79 ± 0.98	1.18 ± 1.06	1.85 ± 0.93	0.99 ± 1.05	0.000
Cardiovascular disease, n (%)	36 (16.5%)	32 (21.6%)	5 (25.0%)	73 (18.9%)	0.366
Previous COPD diagnosis, n (%)	35 (16.1%)	52 (35.1%)	17 (85.0%)	104 (26.9%)	0.000
Current treatment
Short-acting beta-agonist, n (%)	23 (10.6%)	33 (22.3%)	9 (45.0%)	65 (16.8%)	0.000
Long-acting beta-agonist, n (%)	29 (13.3%)	38 (25.7%)	14 (70.0%)	81 (21.0%)	0.000
Anticholinergics, n (%)	15 (6.9%)	29 (19.6%)	13 (65.0%)	57 (14.8%)	0.000
Methylxanthines, n (%)	2 (0.9%)	3 (2.0%)	2 (10.0%)	7 (1.8%)	0.014
Inhaled corticosteroids, n (%)	32 (14.7%)	43 (29.1%)	14 (70.0%)	89 (23.1%)	0.000
Mild respiratory exacerbations last year	0.17 ± 0.78	0.19 ± 0.61	1.60 ± 4.63	0.25 ± 1.28	0.000
Moderate respiratory exacerbations last year	0.30 ± 0.68	0.41 ± 0.91	1.50 ± 2.59	0.40 ± 0.99	0.000
Hospitalizations last year	0.014 ± 0.12	0.02 ± 0.18	0.70 ± 1.34	0.05 ± 0.36	0.000

Values are mean ± SD or frequency. Abbreviations: BMI = body mass index.

Figure 1.  Frequency distribution of the total scores of several multi-dimensional indices on a population-based sample of COPD patients.

Table 2.  Distribution of the multi-dimensional indices in the population-based sample of COPD patients, by GOLD airflow limitation

	Mild (n = 218)	Moderate (n = 148)	Severe (n = 20)	Total (n = 386)	p
BODE index	0.61 ± 0.85	1.36 ± 1.39 †	5.47 ± 1.60 †‡	1.14 ± 1.53	0.000
ADO index	2.18 ± 1.29	3.13 ± 1.66 †	5.75 ± 1.33 †‡	2.73 ± 1.67	0.000
DOSE index	0.78 ± 0.82	1.22 ± 0.94 †	3.60 ± 0.82 †‡	1.09 ± 1.07	0.000
mDOSE index	0.87 ± 0.97	1.36 ± 1.13 †	3.95 ± 1.00 †‡	1.25 ± 1.26	0.000
e-BODE index	0.63 ± 0.86	1.38 ± 1.41 †	5.80 ± 1.94 †‡	1.17 ± 1.60	0.000
BODEx index	0.47 ± 0.71	1.15 ± 1.10 †	4.95 ± 1.36 †‡	0.96 ± 1.35	0.000
COPD Prognostic Index	16.95 ± 12.05	22.15 ± 16.02 §	52.35 ± 12.77 †‡	21.10 ± 16.04	0.000
SAFE index	0.51 ± 0.87	1.86 ± 1.17 †	5.20 ± 1.78 †‡	1.27 ± 1.52	0.000
Hospitalization Risk Score	—	54.14 ± 20.62	92.60 ± 34.17 ‡	62.07 ± 28.50	0.000


Values are mean ± SD. Comparisons between groups by ANOVA with Bonferroni post-hoc comparisons: †p < 0.001 vs. mild COPD patients; §p < 0.01 vs. mild COPD patients; ‡p < 0.001 vs. moderate COPD patients.

Table 3.  Population-based distribution of new GOLD grades, BODE, e-BODE, BODEx and SAFE scores

	Frequency	95% confidence interval
GOLD grade
A	53.1	48.1–58.1
B	34.2	29.5–38.9
C	2.3	0.8–3.8
D	10.4	7.3–13.4
BODE quartile
I	85.8	81.9 –89.6
II	9.8	6.5 –13.1
III	2.5	0.8 –4.3
IV	1.9	0.4 –3.4
e-BODE quartile
I	85.4	81.6–89.3
II	9.8	6.5–13.1
III	2.2	0.6–3.8
IV	2.5	0.8–4.3
BODEx quartile
I	88.3	85.1–91.5
II	8.1	5.3–10.8
III	2.9	1.2–4.5
IV	0.8	0–1.7
SAFE stage
I	83.2	79.1–87.3
II	12.3	8.7–12.3
III	3.2	1.2–5.1
IV	1.3	0–2.5

Figure 2.  Discriminative capacity of several multi-dimensional indices to identify COPD patients with a very low level of daily physical activity. Adjusted odds ratio for sex, age and smoking habit.

Table 4.  Multivariate model to predict the daily physical activity in COPD patients

	Unstandardized regression coefficients		95% Confidence interval for B		Standardized regression coefficients
	B	SE	Lower limit	Upper limit	B	p-value	R^2	R^2 change
Constant	1.028	3.264	–5.496	7.552	–	–	–	–
SAFE stage	4.617	0.947	2.724	6.510	0.493	<0.001	0.255	–
Sex †	8.386	2.545	3.298	13.473	0.333	0.002	0.366	0.111


†Sex (1 = male; 2 = female).

Table 5.  Independent multi-dimensional indices related with co-morbidity (Charlson index) in COPD patients

	Unstandardized regression coefficients		95% Confidence interval for B		Standardized regression coefficients
	B	SE	Lower limit	Upper limit	B	p- value	R^2	R^2 change
Constant	0.08147	0.149	–0.211	0.374	–	-	–	–
ADO index	0.184	0.043	0.100	0.268	0.295	<0.001	0.148	–
SAFE stage	0.322	0.128	0.070	0.574	0.172	0.013	0.170	0.022

Table 6.  Adjusted risk factors for the presence of cardiovascular morbidity in COPD patients

	Adjusted odds ratio*	95% confidence interval	p
BMI	1.122	1.042–1.209	0.002
ADO index	1.330	1.030–1.717	0.029
SAFE index			0.051
Stage I	1	—	—
Stage II	3.246	1.264–8.333	0.014
Stage III	0.408	0.039–4.288	0.455
Stage IV	1.709	0.101–29.023	0.711


*Adjusted for sex, age and smoking habit. Abbreviations: BMI = body mass index.