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Table 1 Baseline characteristics of 203 patients with 2009 A/H1N1 influenza

From: The value of radiographic findings for the progression of pandemic 2009 influenza A/H1N1 virus infection

  All Group 1 Group 2 Group 3 Group 4 P- values
(N = 203) (N = 46) (N = 64) (N = 64) (N = 29)  
Age (years)       
0–1 15 (7%) 5 (11%) 7 (11%) 2 (3%) 1 (3%) 0.198
1–5 56 (28%) 15 (33%) 20 (31%) 13 (20%) 8 (28%)
5–10 98 (48%) 15 (33%) 28 (44%) 39 (61%) 16 (55%)
>10 34 (17%) 11 (23%) 9 (14%) 10 (16%) 4 (14%)
Gender male 132(65%) 27 (59%) 44 (69%) 45 (70%) 16 (55%) 0.358
Underlying medical conditions       0.004
none 60 (30%) 13 (28%) 16 (25%) 24 (38%) 7 (24%)
asthma 57 (28%) 8 (17%) 20 (31%) 22 (34%) 7 (24%)
asthmatic diseases+ 29 (14%) 2 (5%) 10 (16%) 9 (14%) 8 (28%)
other respiratory problems++ 8 (4%) 3 (6%) 2 (3%) 2 (3%) 1 (4%)
immunocompromised * 4 (2%) 2 (5%) 0 (0%) 2 (3%) 0 (0%)
others** 45 (22%) 18 (39%) 16 (25%) 5 (8%) 6 (20%)
Heart Rate on admission 146 138 150 150 150 0.072
(bpm, median) IQR 133-160 100-175 128-172 121-179 128-172
Respiratory Rate on admission 37 24 40 38 40 < 0.001
(bpm, median) IQR 28-42 14-34 20-60 23-53 17-63
Body Temperature on admission 38.5 38.7 38.4 38.4 38.2 0.530
(°C, median) IQR 37.9-39.2 37.4-40.0 37.3-39.5 37.0-39.8 36.6-39.9
SpO2 on admission 94 98 96 93 94 < 0.001
(%, median) IQR 93-98 95-100 91-100 88-98 88-100
O2 demand on admission YES 39 (19%) 4 (9%) 9 (14%) 19 (30%) 7 (24%) 0.025
O2 demand during admission YES 129 (64%) 10 (22%) 41 (64%) 53 (83%) 25 (86%) 0.002
Time from the onset of illness (hr)       
0–5 38 (19%) 11(23%) 14 (22%) 11 (17%) 2 (7%) 0.976
6–11 27 (13%) 1 (2%) 8 (12%) 13 (20%) 5 (17%)
12–23 61 (30%) 18 (41%) 14 (22%) 15 (23%) 14 (49%)
24–47 42 (21%) 11 (23%) 13 (20%) 11 (17%) 7 (24%)
48 - 20 (10%) 3 (7%) 8 (12%) 9 (14%) 0 (0%)
Unknown 15 (7%) 2 (4%) 7 (12%) 5 (9%) 1 (3%)
Systemic steroid use YES 84 (41%) 10 (22%) 24 (38%) 33 (52%) 17 (59%) 0.34
Antibiotics use YES 92 (45%) 5 (11%) 23 (36%) 51 (80%) 13 (45%) 0.10
Antiviral use YES 191 (94%) 42 (91%) 60 (94%) 62 (97%) 27 (93%) 0.994
  1. + Asthmatic diseases were defined as disorders including asthmatic bronchitis and cough variant asthma, but without a diagnosis of asthma.
  2. ++ “Other respiratory problems” included pulmonary hypoplasia, extralobar pulmonary sequestration, tracheal stenosis, and chronic lung disease.
  3. * “Immunocompromised” was used to indicate patients with nephrotic syndrome, and who were post-living donor liver transplantation for biliary atresia and propionic acidemia.
  4. ** Others included chromosomal abnormalities, renal diseases, and congenital heart diseases.
  5. IQR: interquartile range.
  6. The definitions of group 1–4 were as follows:
  7. 1) Group 1. Normal finding.
  8. 2) Group 2. hilar and/or peribronchial markings alone.
  9. 3) Group 3. consolidation; patients with chest radiographs presenting with consolidation, and with or without other findings.
  10. 4) Group 4. other findings; patients whose chest radiographs included reticulonodularity or diffuse haziness of the lungs +/− hilar and/or peribronchial markings, hyperinflation, mediastinal emphysema, or subcutaneous emphysema.