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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