Table 1.

Clinical characteristics of patients by timing of dialysis initiationa

FactorLow(BUN ≤ 76 mg/dl; n = 122)High(BUN > 76 mg/dl; n = 121)P
Mean age (yr)54.457.70.11
% Female47300.007
Race/ethnicity (%)0.93
    white7478
    black77
    Asian107
    Hispanic76
    other22
% Surgery before/at ICU admission55550.90
% History of hypertension48460.84
% History of diabetes22260.43
% History of COPD8240.008
% History of heart failure20260.27
% History of coronary artery disease26270.85
No. failed organ systems (median [IQR]4 (3 to 4)3 (2 to 4)0.008
% Central nervous system failure31200.04
% Liver failure43330.01
% Hematologic failure35210.01
% Cardiovascular failure46440.74
% Respiratory failure83720.04
% Mechanical ventilation55620.34
% Sepsis or septic shock37460.14
Mean heart rate (per min)101940.005
Mean SBP (mmHg)1121150.09
Mean DBP (mmHg)58560.52
Mean temperature (°C)36.937.00.56
Median urine output (mL)4234240.64
Median total bilirubin (mg/dl)2.63.10.26
Mean creatinine (mg/dl)3.44.7<0.0001
Mean BUN (mg/dl)47.4114.9<0.0001
Mean platelets (1000/mm3)1301480.22
Mean pH7.357.350.96
Mean potassium (mEq/L)4.54.70.22
Mean bicarbonate (mEq/L)20.821.50.35
Mean leukocyte (1000/mm3)14.114.70.67
Mean hemoglobin (g/dl)10.310.30.92
Parenteral or enteral nutrition support (%)3365<0.001
Initial dialysis with CRRT (%)6943<0.001
  • a Variable n = for each parameter; for discrete variables, missing considered absent. BUN, blood urea nitrogen; COPD, chronic obstructive pulmonary disease; DBP, diastolic BP; ICU, intensive care unit; IQR, interquartile range; SBP, systolic BP; CRRT, continuous renal replacement therapy.