0–4 yr. n=310 5–17 yr. n=59 18–59 yr. n=76 ≥60 yr. n=152
P-value
Laboratory findings
White blood cell count, ×109 per L 7.98 (6–10.8) 8.0 (6.4–10.4) 7.3 (5.5–10.0) 7.5 (5.9–10.7) 0.485
<4
6/280 (2.1%)
/49 (0%)
7/71 (9.9%)
10/145 (6.9%)
0.037
4–10
189/280 (67.5%)
35/49 (71.4%)
47/71 (66.2%)
92/145 (63.4%)
≥10
85/280 (30.4%)
14/49 (28.6%)
17/71 (23.9%)
43/145 (29.7%)
Lymphocyte count, × 109 per L 3 (2–4.4) 2.05 (1.225–2.875) 1.4 (0.9–2.15) 1.1 (0.7–1.7) <0.001
<1000
14/277 (5.1%)
8/48 (16.7%)
19/68 (27.9%)
54/130 (41.5%)
<0.001
Neutrophil proportion, % 49 (32.0–62.5) 64.9 (58.1–74.0) 72.8 (57.3–83.3) 76.5 (67.6–84.3) <0.001
<50
138/271 (50.9%)
7/49 (14.3%)
11/70 (15.7%)
5/139 (3.6%)
<0.001
50%–69%
92/271 (33.9%)
24/49 (49%)
19/70 (27.1%)
35/139 (25.2%)
≥70%
41/271 (15.1%)
18/49 (36.7%)
40/70 (57.1%)
99/139 (71.2%)
Platelet count, × 109 per L 294 (225–368.5) 292 (225–355.5) 200 (166.25–260) 197 (154–246) <0.001
<100
1/285 (0.4%)
/51 (0%)
4/69 (5.8%)
10/154 (6.5%)
<0.001
Creatinine, μmol/L 22 (18.6–26.9) 36.9 (29.7–39.8) 60 (51–78) 69.5 (56.5–87.6) <0.001
>133
/98 (0%)
/16 (0%)
/25 (0%)
7/94 (7.4%)
0.02
Blood urea nitrogen, mmol/L 2.8 (2.1–3.625) 2.7 (2.3–4) 4.6 (2.95–6.025) 5.1 (3.9–7.55) <0.001
≥7.14
2/101 (2%)
1/15 (6.7%)
2/26 (7.7%)
27/90 (30%)
<0.001
Alanine aminotransferase, U/L 20 (14–28) 13 (10–37.5) 22 (11.5–36.5) 16 (11–26) 0.174
Aspartate aminotransferase, U/L 34.5 (28.75–44) 27 (20–31.5) 24 (17–34) 21 (17–32.75) <0.001
>40
37/106 (34.9%)
2/17 (11.8%)
4/26 (15.4%)
12/92 (13%)
0.001
Creatine kinase, U/L 77 (52.8–119.0) 81 (50.0–105.3) 78 (55.0–131.8) 77 (45.0–134.0) 0.951
Creatine kinase MB fraction, U/L 21 (15.5–29) 19.5 (14–21) 10.5 (2.8–17.3) 10 (5.3–14.0) <0.001
>25
31/102 (30.4%)
3/17 (17.6%)
2/19 (10.5%)
2/79 (2.5%)
<0.001
Sodium, mmol/L 137.5 (136–139) 139 (136–139.1) 138 (135.5–142) 138 (135–140) 0.619
Erythrocyte sedimentation rate, mm/hour 21 (15.5–29.3) 42 (14–59) 24.5 (15.8–48.8) 35 (25–60) 0.267
C-reactive protein, mg/L 8 (6–8) 9 (8–80) 18.55 (12.25–120.175) 26 (8.5–81.8) <0.001
≥10
13/56 (23.2%)
3/7 (42.9%)
14/16 (87.5%)
39/53 (73.6%)
<0.001
Procalcitonin, ng/mL 0.15 (0.1–0.39) 0.39 (0.25–0.64) 0.055 (0.02–0.1675) 0.09 (0.05–0.31) 0.019
The arterial partial pressure of oxygen 97 (77.25–105.25) 96 (91–98) 82 (65–98) 92 (74–96) 0.099
Saturation of arterial blood oxygen, % 97 (92–99) 94.5 (89–97) 94 (88–99) 94 (88–98) 0.135
<90
6/35 (17.1%)
2/8 (25%)
7/23 (30.4%)
33/105 (31.4%)
0.346
Radiographic findings
Monolateral involvement of chest radiographs 40 (12.9%) 12 (20.3%) 16 (21.1%) 46 (30.3%) <0.001
bilateral involvement of chest radiographs 32 (10.3%) 4 (6.8%) 19 (25%) 44 (28.9%)