Table 1.

Characteristics of cohort of post–cardiac surgery patients enrolled in study

CharacteristicAKIN Stage 1 or 2 and SurvivedAKIN Stage 3 or DeathP Value
Patients (n)17826
Age (yr)a,b68 (59.0–76.0)65.5 (58.0–79.0)0.97
Women, % (n)32.6 (58)38.5 (10)0.71
White, % (n)70.2 (125)69.2 (18)0.9
Surgical variablesa
 CABG, % (n)46.6 (83)34.6 (9)0.35
 Valve replacement, % (n)28.7 (51)26.9 (7)0.96
 CABG + valve, % (n)16.9 (30)23.1 (6)0.62
 Other, % (n)7.9 (14)15.4 (4)0.37
 Bypass, % (n)86.0 (153)88.5 (23)0.97
 Bypass time (min)b141.0 (83.0–192.0)159.5 (62.0–203.0)0.66
 Collection time (hr postop)b21.8 (19.2–43.0)21.6 (19.2–33.6)0.69
Serum creatinine (mg/dl)
 Preoperativeb1.1 (0.9–1.3)1.3 (1.0–1.8)0.02
 At collectionb1.6 (1.3–1.9)1.9 (1.6–3.1)<0.001
  Increase at collection (%)b41 (30–56)64 (35–80)0.003
Outcomes
 Time to maximum creatinine (d)b,c2.0 (1.0–3.0)5.0 (3.75–8.0)<0.001
 Time to discharge or death (d)b,c7.0 (6.0–10.0)14.0 (9.75–24.75)<0.001
 AKIN stage 3, % (n)0 (0)84.6 (22)<0.001
 AKIN stage 3 or death, % (n)0 (0)100 (26)<0.001
 Death, % (n)0 (0)34.6 (9)<0.001
 Renal replacement therapy, % (n)0 (0)50.0 (13)<0.001
  • Statistical significance was determined by the chi-squared test for categorical variables and the Mann-Whitney U test for continuous variables. AKIN, Acute Kidney Injury Network; CABG, coronary artery bypass grafting.

  • a Type of surgery is reported as CABG only, valve replacement only, CABG + valve replacement, and other procedures.

  • b Continuous variables are reported as median (interquartile range).

  • c Days are reported as the number of days after surgery.