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Table 1 Descriptive characteristics of patients admitted to the ICU with early or late diagnosis of influenza A (H1N1)pdm09 virus infection and independent factors related to diagnostic delay

From: Delay in diagnosis of influenza A (H1N1)pdm09 virus infection in critically ill patients and impact on clinical outcome

Variable

Early diagnosis (≤2 days)

Late diagnosis (3–7 days)

P value

Odds ratio (95 % confidence interval)

P value

Total patients

1314

745

   

Age (years), mean (SD)

48.43 (15.6)

51.23 (15.0)

0.001

1.02 (1.01–1.03)

0.001

Sex

 Men

744 (56.6)

458 (61.4)

0.032

  

 Women

570 (43.4)

287 (38.5)

Seasonal period

 2009–2012

732 (59.45

499 (40.5)

0.001

2.08 (1.64–2.63)

0.001

 2013–2015

582 (70.3)

246 (29.7)

Influenza vaccine

60 (4.6)

44 (5.9)

0.169

  

Comorbid conditions

 Asthma

148 (11.3)

72 (9.7)

0.262

  

 Chronic obstructive pulmonary disease

235 (17.9)

159 (21.4)

0.054

 Heart failure

122 (9.3)

84 (11.3)

0.146

 Chronic renal failure

81 (6.2)

69 (9.2)

0.013

 Hematological disease

66 (5.0)

64 (8.6)

0.001

 Obesity

459 (34.9)

269 (36.1)

0.574

 Diabetes mellitus

189 (14.4)

116 (15.6)

0.432

 Human immunodeficiency virus infection

32 (2.4)

15 (2.0)

0.540

 Neuromuscular disease

39 (3.0)

16 (2.2)

0.269

 Autoimmune disease

41 (3.1)

28 (3.8)

0.381

 Immunosuppression

105 (8.0)

102 (13.7)

0.001

 Pregnancy

53 (4.0)

29 (3.9)

0.879

APACHE II score, mean (SD)

15 (7)

16 (8)

0.001

SOFA score, mean (SD)

6 (3)

6 (4)

0.001

Presenting clinical manifestations

 Primary viral pneumonia

1129 (85.9)

603 (81.0)

0.004

  

 Coinfection (bacterial pneumonia)

219 (16.7)

133 (17.9)

0.458

Noninvasive mechanical ventilation

482 (36.67

314 (42.2)

0.022

Mechanical ventilation

864 (65.0)

569 (76.4)

0.001

1.58 (1.17–2.13)

0.002

Days on mechanical ventilation, median (IQR)

8 (2–15)

9 (4–20)

0.001

  

Vasoactive drugs

639 (48.6)

425 (57.0)

0.001

Decubitus prono

233 (17.7)

143 (19.52

0.382

Continuous venovenous hemofiltration

103 (7.8)

95 (12.8)

0.001

1.54 (1.08–2.18)

0.016

Corticoids

527 (40.1)

335 (45.0)

0.043

  

Days on corticoids, median (IQR)

7 (4–10)

7 (5–12)

0.071

Days until ICU admission, median (IQR)

1 (1–1)

1 (1–3)

0.001

1.26 (1.17–1.35)

0.001

Length of ICU stay (days), median (IQR)

8 (4–17)

10 (5–20)

0.001

  

Length of hospital stay (days), median (IQR)

14 (8–25)

18 (10–30)

0.001

Days until oseltamivir therapy, median (IQR)

4 (2–6)

5 (3–7)

0.001

Mortality rate

225 (17.1)

200 (26.9)

0.001

  1. Data expressed as frequencies (percentages) unless otherwise stated
  2. APACHE Acute Physiology and Chronic Health Evaluation, IQR interquartile range (25th–75th percentile), SD standard deviation, SOFA Sepsis-related Organ Failure Assessment