Skip to main content

Table 1 Comparison of participants included versus excluded due to missing data

From: Acute kidney injury among critically ill patients with pandemic H1N1 influenza A in Canada: cohort study

Characteristic Overall Included Excluded P value
(n = 671) (n = 562) (n = 109)
Age (yr) 47.9 (15.2) 48.0 (15.0) 47.1 (16.4) 0.55
Female sex 363 (54.1) 300 (53.4) 63 (57.8) 0.40
Ethnicity (n=652, 555, 97)     
   White/Caucasian 378 (58.0) 327 (58.9) 51 (52.6) 0.41
   Unknown/Mixed/Other 143 (21.9) 117 (21.1) 26 (26.8)  
   Aboriginal 85 (13.0) 74 (13.3) 11 (11.3)  
   Asian 46 (7.1) 37 (6.7) 9 (9.3)  
Any co-morbidity 607 (90.5) 513 (91.3) 94 (86.2) 0.10
   Obesity 167 (24.9) 150 (26.7) 17 (15.6) 0.01
   Diabetes mellitus 170 (25.3) 146 (26.0) 24 (22.0) 0.38
   Chronic obstructive pulmonary disease 119 (17.7) 98 (17.4) 21 (19.3) 0.65
   Alcohol abuse 83 (12.4) 74 (13.2) 9 (8.3) 0.15
   Chronic kidney disease 56 (8.4) 48 (8.5) 8 (7.3) 0.68
H1N1 status
   Confirmed 574 (85.5) 479 (85.2) 95 (87.2) 0.60
   Probable 97 (14.5) 83 (14.8) 14 (12.8)
Days of symptoms pre-hospital (n = 635, 532, 103) 4.0 (2.0-7.0) 4.0 (2.0-7.0) 3.0 (1.0-6.0) 0.01
Days of symptoms pre-ICU (n = 653, 549, 104) 5.0 (3.0-8.0) 5.0 (3.0-8.0) 4.5 (2.5-7.0) 0.04
Day 1 support, physiology, and laboratory values
APACHE II score (n = 594, 508, 86) 20.8 (9.8) 21.1 (9.2) 19.1 (13.1) 0.19
SOFA score (n = 411, 361, 50) 11.2 (3.7) 11.2 (3.8) 10.9 (3.6) 0.61
Invasive mechanical ventilation (n = 652, 553, 99) 431 (66.1) 384 (69.4) 47 (47.5) <0.0001
Inotrope or vasopressor 281 (41.9) 251 (44.7) 30 (27.5) 0.0009
Mean arterial pressure (mmHg) (n = 613, 522, 91) 74.1 (18.7) 74.4 (18.9) 72.5 (17.4) 0.37
Heart rate (beats/min) (n = 504, 433, 71) 104.1 (24.0) 104.5 (24.1) 101.5 (23.3) 0.33
Temperature (°C) (n = 472, 405, 67) 37.6 (1.3) 37.6 (1.2) 37.5 (1.8) 0.48
PaO2/FiO2 (n = 570, 496, 74) 160 (120) 153 (96) 212 (215) 0.02
CK (U/L) (n = 270, 230, 40) 272 (91-776) 293 (91-835) 224 (87-663) 0.41
CK > 5000 IU/L (n = 270, 230, 40) 15 (5.6) 13 (5.7) 2 (5.0) 1.00
WBC (109/L) (n = 471, 409, 62) 9.7 (6.5) 9.5 (6.5) 10.6 (7.0) 0.24
Albumin (g/L) (n = 315, 275, 40) 26.6 (7.2) 26.2 (7.0) 28.7 (8.0) 0.04
Platelets (109/L) (n = 608, 520, 88) 190 (96) 188 (96) 204 (95) 0.16
Urea (mmol/L) (n = 89, 76, 13) 10.2 (19.7) 10.5 (21.0) 8.4 (9.4) 0.56
Creatinine (μmol/L) (n = 626, 537, 89) 125 (120) 124 (120) 131 (119) 0.59
Urine output (mL/24 hr) (n = 489, 431, 58) 1440 (1082) 1439 (1055) 1446 (1278) 0.97
Interventions (ICU day 1, 3, 7, 14, or 28)
Renal replacement therapy (n = 670, 561, 109) 91 (13.6) 85 (15.2) 6 (5.5) 0.007
Invasive mechanical ventilation (n = 669, 562, 107) 568 (84.9) 499 (88.8) 69 (64.5) <0.0001
Inotropes or vasopressors 373 (55.6) 339 (60.3) 34 (31.2) <0.0001
Antiviral treatment 620 (92.4) 530 (94.3) 90 (82.6) <0.0001
Outcome
Days of ICU stay (n = 640, 539, 101) 11.0 (6.0-19.0) 11.0 (7.0-20.0) 5.0 (2.0-13.0) <0.0001
Days of hospital stay (n = 626, 523, 103) 18.0 (11.0-34.0) 19.0 (12.0-35.0) 12.0 (5.0-24.0) <0.0001
Hospital mortality (n = 649, 545, 104) 142 (21.9) 113 (20.7) 29 (27.9) 0.11
  1. Patients described in this table were excluded because of insufficient data to determine the RIFLE classification. For each variable, we specify (n) with data if it differs from the total in the first row. Categorical data are presented as n (%) and continuous data as mean (SD) or median (Q1-Q3).