Table 2.

Unadjusted and adjusted RRs for preoperative ACR to predict development of postoperative stage 1 or stage 2 AKI, by age group

Preoperative ACRStage 1 or Higher AKIaStage 2 or 3 AKIa
Stage 1 AKIUnadjusted RRAdjusted RRbStage 2 AKIUnadjusted RRAdjusted RRb
n (% of Group)95% CI95% CIn (% of Group)95% CI95% CI
Participants aged 1 mo–<2 yr at surgery
 No. of events6127
 <30 mg/g (n=33)19 (58)1110 (30)11
 30–<300 mg/g (n=67)34 (51)0.88 (0.61, 1.28)0.84 (0.57, 1.24)15 (22)0.74 (0.37, 1.46)0.73 (0.37, 1.45)
 ≥300 mg/g (n=14)8 (57)0.99 (0.58, 1.7)1.06 (0.62, 1.82)2 (14)0.47 (0.12, 1.88)0.53 (0.13, 2.1)
Participants aged ≥2 yr at surgeryc
 Number of events4316
 <10 mg/g (n=50)12 (24)113 (6)11
 10–<30 mg/g (n=55)17 (31)1.29 (0.68, 2.42)1.03 (0.55, 1.92)7 (13)2.12 (0.58, 7.76)1.8 (0.43, 7.55)
 ≥30 mg/g (n=36)14 (39)1.62 (0.85, 3.08)1.2 (0.66, 2.15)6 (17)2.78 (0.74, 10.38)2.82 (0.82 ,9.71)
  • RR, relative risk; ACR, albumin/creatinine ratio; CI, confidence interval; AKIN, Acute Kidney Injury Network; RACHS-1, risk adjustment for congenital heart surgery-1; eGFR, estimated GFR.

  • a The outcomes were the presence of stage 1 AKI or worse (based on AKIN staging; includes participants with stages 2 or 3 AKI) or of stage 2 AKI or worse. To convert to SI units (mg albumin per mmol creatinine), divide ACR by 8.84.

  • b In the group aged <2 years, RRs are adjusted for age, sex, white (versus nonwhite), elective versus urgent surgery, RACHS-1 score ≥3 versus <3, preoperative eGFR percentile, and study site.

  • c In the group aged ≥2 years, RRs are adjusted for age (2–<6 years versus ≥6 years), sex, white versus nonwhite, elective versus urgent surgery, RACHS-1 score ≥3 versus <3, preoperative eGFR percentile, and study site.