Table 1 Univariate analysis performed in the derivation sample (n = 1252)

Age^a

72.5 (9.8)

77.7 (8.6)*

72.3 (9.8)

77.3 (8.9)*

Sex (Male)

1105 (91.6)

42 (91.3)

1075 (91.7)

72 (91.1)

Baseline FEV1 %

**

   ≥50

42 (4.2)

0 (−)

40 (4.1)

2 (3.0)

   30 < FEV1 % < 50

295 (29.4)

6 (14.6)

286 (29.2)

15 (22.7)

   ≤30

666 (66.4)

35 (85.4)

652 (66.7)

49 (74.2)

Charlson Comorbidity Index^a

2.22 (1.52)

3.11 (2.23)*

2.19 (1.50)

3.15 (2.00)*

   >2

374 (31.0)

24 (52.2)**

351 (29.9)

47 (59.5)*

Diabetes mellitus

238 (19.8)

19 (41.3)*

230 (19.7)

27 (34.2)**

Cardiopathy

345 (28.6)

24 (52.2)**

327 (27.9)

42 (53.2)*

Previous LT-DOT or NIMV at home

380 (31.5)

34 (73.9)*

367 (31.3)

47 (59.5)*

Number of previous admissions due to eCOPD

0.85 (1.38)

1.04 (1.28)

0.84 (1.38)

1.08 (1.37)

   0-1

970 (80.4)

35 (76.1)

445 (80.6)

60 (76.0)

   2

103 (8.5)

2 (4.4)

101 (8.6)

4 (5.1)

   ≥3

133 (11.0)

9 (19.6)

127 (10.8)

15 (19.0)

Glasgow Coma Score – <15

32 (2.7)

7 (15.2)*

30 (2.6)

9 (11.4)*

Heart rate upon ED arrival (≥120)

104 (8.6)

8 (17.4)

99 (8.4)

13 (16.5)

Use of inspiratory accessory muscle upon ED arrival

256 (21.2)

23 (50.0)*

252 (21.5)

27 (34.2)**

Paradoxical breathing upon ED arrival

52 (4.3)

9 (19.6)*

48 (4.1)

13 (16.5)*

pH upon ED arrival

*

**

   ≥7.35

986 (88.6)

30 (68.2)

958 (88.4)

58 (79.5)

   7.26-7.34

106 (9.5)

8 (18.2)

105 (9.7)

9 (12.3)

   <7.26

21 (1.9)

6 (13.6)

21 (1.9)

6 (8.2)

PCO2 upon ED arrival

*

*

   ≤45

613 (58.5)

10 (23.3)

596 (58.4)

27 (38.0)

   46-55

233 (22.2)

14 (32.6)

226 (22.2)

21 (29.6)

   56-65

111 (10.6)

9 (20.9)

109 (10.7)

11 (15.5)

   >65

91 (8.7)

10 (23.3)

89 (8.7)

12 (16.9)

MRC breathlessness scale

*

*

   1-2

404 (33.5)

2 (4.4)

401 (34.2)

5 (6.3)

   3

227 (18.8)

3 (6.5)

220 (18.8)

10 (12.7)

   4

329 (27.3)

11 (23.9)

319 (27.2)

21 (26.6)

   5

119 (9.9)

19 (41.3)

109 (9.3)

29 (36.7)

   missing

127 (10.5)

11 (23.9)

124 (10.6)

14 (17.8)