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Table 1 Baseline characteristics of the study patients

From: Evolution of chronic renal impairment and long-term mortality after de novo acute kidney injury in the critically ill; a Swedish multi-centre cohort study

Baseline characteristics No acute kidney injury (n = 92,509) Acute kidney injury (n = 5,273) P -value
Mean age, years 59.3 (19.6) 67.9 (14.2) <0.001
Median age, years 63 (45 to 75) 70 (61 to 78)  
Length of ICU stay, hours 23 (12 to 53) 68 (26 to 189) <0.001
Women 40411 (43.6) 2086 (39.6) <0.001
Number of admissions per patient, mean (SD) 1.31 (0.89) 1.29 (0.74) 0.19
Number of admissions per patient, median (IQR) 1 (1 to 1) 1 (1 to 1)  
Highest potassium, mmol/L 4.1 (3.9 to 4.5) 4.7 (4.1 to 5.5) <0.001
Number 16069 1605  
Highest sodium, mmol/L 139 (136 to 142) 137 (134 to 141) <0.001
Number 16121 279  
Lowest sodium, mmol/L 136 (133 to 139) 133 (130 to 137) <0.001
Number 16121 1604  
Highest bilirubin, μmol/L 10 (6 to 17) 14 (8 to 26) <0.001
Number 16863 1768  
Lowest arterial pH 7.36 (7.30 to 7.41) 7.29 (7.19 to 7.38) <0.001
Number 40449 3968  
Lowest bicarbonate, mmol/L 23 (20 to 25) 18 (14 to 22) <0.001
Number 3662 593  
Maximum creatinine (μmol/L) 80 (63 to 105) 254 (164 to 422) <0.001
Number 47441 4076  
Maximum urea (mmol/L) 6.7 (4.3 to 10.1) 17.5 (11 to 26) <0.001
Number 2717 532  
Lowest thrombocyte count, x 109/L 230 (170 to 296) 199 (123 to 291) <0.001
Number 32586 2695  
Apache II score 14 (8 to 20) 25 (20 to 32) <0.001
Number 17231 1620  
SAPS II score 25 (0 to 41) 55 (42 to 70) <0.001
Number 15376 764  
SAPS III score 52 (43 to 63) 68 (59 to 77) <0.001
Number 18326 1437  
Intervention, number (%)a    
Invasive mechanical ventilation, numbera 7155 (7.7) 994 (18.9) <0.001
Acute surgerya 7282 (7.8) 662 (12.6) <0.001
Elective surgerya 5237 (5.7) 295 (5.6) 1.0
Charlson comorbidity score, meanb (SD) 1.78 (2.2) 2.64 (2.5) <0.001
Comorbidity, number (%)    
Myocardial infarction 11896 (12.9) 986 (18) <0.001
Congestive cardiac failure 12521 (13.5) 1324 (25.1) <0.001
Peripheral vascular disease 8921 (9.6) 704 (13.4) <0.001
Cerebrovascular disease 15658 (16.9) 808 (15.3) <0.001
Dementia 1840(2.0) 99(1.9) 0.612
Chronic obstructive pulmonary disease 12999 (14.1) 808 (15.3) 0.010
Rheumatological disease 3311 (3.6) 269 (5.1) <0.001
Peptic ulcer disease 5693 (6.2) 423(8.0) <0.001
Cancer 15726 (17.0) 1262 (24.0) <0.001
Metastatic disease 1918 (3.6) 304 (4.7) <0.001
Mild liver disease 45021 (4.9) 369(7.0) <0.001
Moderate or severe liver disease 3319 (2.1) 249 (5.8) <0.001
Uncomplicated diabetes 13168 (14.2) 1372 (26.2) <0.001
Diabetes with complications 4660 (5.0) 523 (9.9) <0.001
Paraplegia 1787 (1.9) 90 (1.7) 0.287
HIV 125 (0.14) 4 (0.08) 0.328
  1. Values are median (IQR) or n (%). if not otherwise stated. Information on laboratory data were obtained from the severity scorings systems APACHE II, SAPS II and SAPS III. APACHE and SAPS2 record the highest or lowest values recorded during the first 24 hours of ICU admission, and SAPS3 records values from 1 hour before until 1 hour after ICU admission. Values for scoring systems were not available in all patients; number denotes the number of patients in which this information was recorded. aIntervention codes were also under-reported and therefore the number of patients in whom these data were available is detailed in the table. Reporting of all other baseline characteristics is complete. bCharlson score is not age-adjusted. APACHE, acute physiology and chronic health evaluation; SAPS, simplified applied physiology score.