Table 2 Factors associated with an unfavourable outcome in the episodes initially admitted to the intensive care unit (N = 1369)

Type of hospital

 Academic hospital

88/726 (12%)

129/643 (20%)

1.6 (1.2–2.2)*

1.59 (1.04–2.43)

0.03

 Large non-academic hospital

327/726 (45%)

301/643 (47%)

Reference

–

–

 Regional hospital

311/726 (43%)

213/643 (33%)

0.7 (0.6–0.9)*

0.79 (0.58–1.08)

0.145

 Age (years)^a

59 (45–66)

63 (54–72)

–

–

–

  16 – 39

140/718 (19%)

49/637 (8%)

0.4 (0.3–0.6)*

0.59 (0.37–0.96)

0.03

  40–70

483/718 (67%)

394/637 (62%)

Reference

–

–

   > 70

95/718 (13%)

194/637 (30%)

2.5 (1.9–3.3)*

2.86 (1.98–4.14)

 < 0.001

 Female sex

337/726 (46%)

295/643 (46%)

1.0 (0.8–1.2)

1.01 (0.76–1.36)

0.925

 Otitis and/or sinusitis on admission

316/709 (45%)

201/608 (33%)

0.6 (0.5–0.8)*

0.75 (0.54–1.04)

0.08

 Immunocompromised state

207/726 (29%)

251/643 (39%)

1.6 (1.3–2.0)*

–

–

 Active cancer

27/723 (4%)

38/637 (6%)

1.7 (1.0–2.7)

0.67 (0.32–1.40)

0.288

 Diabetes mellitus

97/725 (13%)

109/638 (17%)

1.3 (1.0–1.8)

1.13 (0.74–1.73)

0.568

 HIV

6/726 (1%)

5/641 (1%)

1.2 (0.4–3.6)

0.75 (0.16–3.44)

0.707

 Asplenia

12/726 (2%)

15/641 (2%)

1.5 (0.7–3.1)

1.31 (0.49–3.48)

0.594

 Alcoholism

34/725 (5%)

76/639 (12%)

2.7 (1.8–4.2)*

1.71 (1–2.95)

0.05

 Immunosuppressive drugs

58/725 (8%)

62/636 (10%)

1.2 (0.9–1.8)

0.87 (0.50–1.52)

0.627

Clinical signs and symptoms

 Triad**

342/673 (51%)

243/581 (42%)

0.7 (0.6–0.9)*

1.02 (0.74–1.40)

0.900

 Rash

80/651 (12%)

43/551 (8%)

0.6 (0.4–0.9)*

0.92 (0.51–1.68)

0.789

 Seizures

60/703 (9%)

94/591 (16%)

2.1 (1.5–2.9)*

1.57 (1–2.52)

0.05

 Cranial nerve palsy

30/603 (5%)

67/471 (14%)

3.6 (2.4–5.4)*

2.76 (1.61–4.73)

 < 0.001

 Mono-, hemiparesis or aphasia

131/657 (20%)

138/506 (27%)

2.2 (1.6–3.0)*

1.28 (0.82–1.99)

0.280

 Glasgow Coma Scale Score^b

10 (9–13)

9 (7–11)

0.9 (0.8–0.9)*

0.96 (0.90–1.02)

0.136

 Systolic blood pressure(mmHg)^c

142 (124–162)

145 (125–165)

1.00 (1.00–1.01)

–

–

 Heart rate (bpm)^d

99 (84–110)

106 (90–125)

–

–

–

  < 60

20/702 (3%)

9/608 (1%)

0.7 (0.3–1.5)

0.57 (0.20–1.66)

0.304

 60–100

378/702 (54%)

259/608 (43%)

Reference

–

–

  > 100

304/702 (43%)

340/608 (56%)

1.6 (1.3–2.1)*

1.21 (0.89–1.64)

0.217

 Temperature (°C)^e

39.0 (38.1–39.7)

38.8 (37.6–39.6)

0.8 (0.8–0.9)*

0.90 (0.80–1.02)

0.097

Blood results

 Leukocytes (× 10⁹ cells/l)^f

18 (13–23)

16 (10–22)

–

–

–

  < 4.00

6/719 (1%)

35/634 (6%)

4.4 (1.8–10.8)*

4.16 (1.34–12.93)

0.01

 4.00–10.00

87/719 (12%)

116/634 (18%)

Reference

–

–

  > 10.00

626/719 (87%)

483/634 (76%)

0.6 (0.4–0.8)*

0.93 (0.61–1.42)

0.744

 C-reactive protein (per 10 mg/L)^g

16 (8–27)

25 (14–36)

1.04 (1.03–1.05)*

1.03 (1.02–1.04)

 < 0.001

CSF results

 Leukocytes in CSF (per µL)^h

4,219 (1190–9302)

1,567 (252–5,920)

–

–

–

  < 100

44/690 (6%)

104/603 (17%)

1.8 (1.2–2.8)*

1.18 (0.65–2.15)

0.584

 100–999

111/690 (16%)

154/603 (26%)

Reference

–

–

  > 999

535/690 (78%)

345/603 (57%)

0.5 (0.4–0.6)*

0.74 (0.49–1.11)

0.140

 CSF:blood glucose ratioⁱ

0.07 (0.01–0.29)

0.02 (0.01–0.12)

–

–

–

  < 0.25

467/657 (71%)

472/555 (85%)

1.5 (0.9–2.6)

2.37 (1.01–5.53)

0.05

 0.26–0.5

159/657 (24%)

63/555 (11%)

0.6 (0.3–1.2)

1.14 (0.47–2.74)

0.775

  > 0.5

31/657 (5%)

20/555 (4%)

Reference

–

–

 Protein (per 10 g/L)^j

0.39 (0.25–0.60)

0.49 (0.30–0.69)

1.00 (0.98–1.01)

–

–

Causative pathogen

 S. pneumoniae

554/726 (76%)

517/643 (80%)

Reference

–

–

 N. meningitidis

97/726 (13%)

27/643 (4%)

0.3 (0.2–0.5)*

0.58 (0.30–1.12)

0.103

 H. influenzae

19/726 (3%)

8/643 (1%)

0.5 (0.2–1.0)

0.41 (0.12–1.35)

0.142

 L. monocytogenes

10/726 (1%)

26/643 (4%)

2.8 (1.3–5.8)*

4.51 (1.67–12.17)

0.003

 Other

46/726 (6%)

65/643 (10%)

1.5 (1.0–2.3)*

1.85 (1.04–3.28)

0.04

Treatment and complications

 Adjunctive dexamethasone

639/711 (90%)

507/614 (83%)

0.5 (0.4–0.7)*

0.77 (0.48–1.23)

0.271

 Mechanical ventilation

255/707 (36%)

460/622 (74%)

4.9 (3.9–6.1)*

2.83 (2.04–3.94)

 < 0.001

 Persistent fever^k

36/690 (5%)

109/571 (19%)

4.3 (2.9–6.5)*

2.13 (1.31–3.47)

0.002

 Circulatory shock

40/688 (6%)

180/584 (31%)

7.3 (5.1–10.5)*

4.70 (2.90–7.63)

 < 0.001