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Table 5 Logistic regression model for acute kidney injury in critically ill pH1N1 patients

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

Variable AKI No AKI Crude OR P value Adjusted OR P value
n = 342 n = 220 (95% CI) (95% CI)
H1N1 details, demographics, and comorbidities
Confirmed H1N1 291 (85.1) 188 (85.5) 0.97 (0.60-1.57) 0.90   
Age (yr) 49.1 (15.1) 46.4 (14.8) 1.01 (1.00-1.02) 0.03 1.00 (0.98-1.02) 0.98
Female sex 177 (51.8) 123 (55.9) 0.85 (0.60-1.19) 0.34 0.86 (0.56-1.32) 0.50
Ethnicity (n = 555, 336, 219)
  White/Caucasian (reference) 204 (60.7) 123 (56.2) 1.00   1.00  
  Unknown/Mixed/ Other 68 (20.2) 49 (22.4) 0.84 (0.54-1.29) 0.42 0.80 (0.46- 1.39) 0.43
  Aboriginal 47 (14.0) 27 (12.3) 1.05 (0.62-1.77) 0.86 1.01 (0.52-1.94) 0.98
  Asian 17 (5.1) 20 (9.1) 0.51 (0.26-1.02) 0.06 0.82 (0.35-1.89) 0.64
Obesity 118 (34.5) 32 (14.6) 3.10 (2.00-4.79) <0.0001 2.94 (1.75-4.91) <0.0001
Diabetes mellitus 107 (31.3) 39 (17.7) 2.11 (1.40-3.20) 0.0004 1.61 (0.96-2.69) 0.07
Chronic obstructive pulmonary disease 56 (16.4) 42 (19.1) 0.83 (0.53-1.29) 0.41   
Alcohol abuse 41 (12.0) 33 (15.0) 0.77 (0.47-1.26) 0.30   
Chronic kidney disease 44 (12.9) 4 (1.8) 7.97 (2.82-22.5) <0.0001 4.50 (1.46-13.82) 0.009
Day 1 support, physiology, and laboratory values
APACHE II score (n = 508, 306, 202) 23.0 (9.6) 18.1 (7.6) 1.07 (1.04-1.09) <0.0001 1.06 (1.03- 1.09) <0.0001
Invasive mechanical ventilation (n = 553, 338, 215) 241 (71.3) 143 (66.5) 1.25 (0.86-1.81) 0.23   
Inotrope or vasopressor 164 (48.0) 87 (39.6) 1.41 (1.00-1.99) 0.05 1.29 (0.82-2.01) 0.27
Mean arterial pressure (mmHg) (n = 522, 315, 207) 73.4 (18.7) 75.9 (19.2) 0.93 (0.85-1.02) 0.14 0.95 (0.85-1.06) 0.32
PaO2/FiO2 (n = 496, 299, 197) 143 (94) 167 (98) 0.97 (0.96-0.99) 0.007 0.98 (0.95- 1.00) 0.04
Platelets (109/L) (n = 520, 313, 207) 184 (95) 194 (96) 0.99 (0.97-1.01) 0.26   
  1. Categorical data are presented as n (%) and continuous data as mean (SD). Heart rate, temperature, creatine kinase, WBC, albumin, and urea were excluded due to a high proportion of missing data. SOFA score was excluded because it was highly collinear with APACHE II score (Pearson r = 0.6). Urine output and creatinine were excluded because they were used to define the outcome. For each variable, we specify n when it differs from the totals in the first row. The final model included 442 patients and did not have evidence of lack of goodness of fit (p = 0.40). ORs for continuous variables refer to an increment of 1 unit (age, APACHE II) or 10 units (mean arterial pressure, PaO2/FiO2, platelets).