Table 1.
Clinical characteristics of low-education patients with chronic obstructive pulmonary disease
| Variables | Total (n = 4098) | High education (n = 840) | Low education (n = 3258) | P-value |
|---|---|---|---|---|
| Age in years, mean (SD) |
66.1 (9.1) |
64.7 (9.6) |
66.4 (8.9) |
<0.05 |
| Age, n (%) |
|
|
|
<0.05 |
|
<65
|
1614 (39.4) |
407 (48.5) |
1207 (37.0) |
|
|
≥65
|
2484 (60.6) |
433 (51.5) |
2051 (63.0) |
|
| Sex, n (%) |
|
|
|
<0.05 |
|
Male
|
3537 (86.3) |
768 (91.4) |
2769 (85.0) |
|
|
Female
|
561 (13.7) |
72 (8.6) |
489 (15.0) |
|
| BMI kg/m2, mean (SD) |
22.5 (3.4) |
22.7 (3.3) |
22.5 (3.4) |
0.158 |
| BMI, n (%) |
|
|
|
0.171 |
|
<18.5
|
483 (11.8) |
89 (10.6) |
394 (12.1) |
|
|
18.5-23.9
|
2286 (55.8) |
458 (54.5) |
1828 (56.1) |
|
|
≥24
|
1329 (32.4) |
293 (349) |
1036 (31.8) |
|
| Smoke status, n (%) |
|
|
|
<0.05 |
|
Never-smoker
|
990 (24.2) |
159 (18.9) |
831 (25.5) |
|
|
Former-smoker
|
1376 (33.6) |
270 (32.1) |
1106 (33.9) |
|
|
Current-smoker
|
1732 (42.2) |
411 (49.0) |
1321 (40.5) |
|
| Smoking, pack/y, median (IQR) |
30 (10-50) |
36 (20-50) |
30 (7.5-50) |
<0.05 |
| Biofuel exposure, n (%) |
|
|
|
<0.05 |
|
Yes
|
1439 (35.1) |
148 (17.6) |
1291 (39.6) |
|
|
No
|
2659 (64.9) |
692 (82.4) |
1967 (60.4) |
|
| FEV1% predicted, mean (SD) |
52.7 (19.5) |
53.6 (18.9) |
52.5 (19.6) |
0.172 |
| FEV1/FVC, mean (SD) |
47.7 (11.9) |
48.1 (12.1) |
47.6 (11.9) |
0.347 |
| GOLD grades, n (%) |
|
|
|
<0.05 |
|
1
|
369 (9.0) |
75 (8.9) |
294 (9.0) |
|
|
2
|
1767 (43.1) |
404 (48.1) |
1363 (41.8) |
|
|
3
|
1475 (36.0) |
264 (31.4) |
1211 (37.2) |
|
|
4
|
487 (11.9) |
97 (11.5) |
390 (12.0) |
|
| GOLD groups, n (%) |
|
|
|
<0.05 |
|
A
|
492 (12.0) |
137 (16.3) |
355 (10.9) |
|
|
B
|
1619 (39.5) |
339 (40.4) |
1280 (39.3) |
|
|
E
|
1987 (48.5) |
364 (43.3) |
1623 (49.8) |
|
| CAT, mean (SD) |
15.6 (6.5) |
14.2 (6.4) |
15.9 (6.5) |
<0.05 |
| CAT, n (%) |
|
|
|
<0.05 |
|
<10
|
777 (19.0) |
208 (24.8) |
569 (17.5) |
|
|
10-19
|
2252 (55.0) |
475 (56.5) |
1777 (54.5) |
|
|
20-29
|
963 (23.4) |
141 (16.8) |
822 (25.2) |
|
|
≥30
|
106 (2.6) |
16 (1.9) |
90 (2.8) |
|
| mMRC, median (IQR) |
2 (1-3) |
2 (1-2) |
2 (1-3) |
<0.05 |
| mMRC, n (%) |
|
|
|
<0.05 |
|
0-1
|
1265 (30.9) |
319 (38.0) |
946 (29.0) |
|
|
≥2
|
2833 (69.1) |
521 (62.0) |
2312 (71.0) |
|
| Therapy, n (%) |
|
|
|
0.081 |
|
LAMA
|
1268 (30.9) |
252 (30.0) |
1016 (31.2) |
|
|
LABA+LAMA
|
58 (1.5) |
14 (1.7) |
44 (1.4) |
|
|
LABA+ICS
|
533 (13.0) |
123 (14.6) |
410 (12.6) |
|
|
LABA+LAMA+ICS
|
1967 (48.0) |
382 (45.5) |
1585 (48.6) |
|
|
Others*
|
272 (6.6) |
69 (8.2) |
203 (6.2) |
|
| Exacerbation in the past year, median (IQR) |
1 (0-2) |
1 (0-2) |
1 (0-2) |
<0.05 |
| Exacerbation in the past year, n (%) |
|
|
|
<0.05 |
|
0
|
1704 (41.6) |
397 (47.3) |
1307 (40.1) |
|
|
1
|
956 (23.3) |
205 (24.4) |
751 (23.1) |
|
|
≥2
|
1438 (35.1) |
238 (28.3) |
1200 (36.8) |
|
| Comorbidities, n (%) |
|
|
|
|
|
Chronic heart disease
|
44 (1.1) |
15 (1.8) |
29 (0.9) |
<0.05 |
|
Hypertension
|
53 (1.3) |
16 (1.9) |
37 (1.1) |
0.079 |
|
Lung cancer
|
34 (0.8) |
7 (0.8) |
27 (0.8) |
0.990 |
|
Diabetes
|
24 (0.6) |
7 (0.8) |
17 (0.5) |
0.309 |
|
Bronchiectasis
|
139 (3.4) |
34 (4.0) |
105 (3.2) |
0.239 |
| Asthma | 994 (24.3) | 243 (28.9) | 751 (23.1) | <0.05 |
BMI – body mass index, COPD – chronic obstructive pulmonary disease, CAT – COPD assessment test, FEV1 – forced expiratory volume in one second, FVC – forced vital capacity, GOLD – Global Initiative for Chronic Obstructive Lung Disease, ICS – inhaled corticosteroids, IQR – interquartile range, LAMA – long-acting muscarinic antagonist, LABA – long-acting β2-agonist, mMRC – modified Medical Research Council, SD – standard deviation, SABA – short-acting β2-agonist, SAMA – short-acting muscarinic agonist
*Others including SAMA, SABA, SAMA+SABA, LAMA+ICS, ICS and no inhalation therapy.