Table 2.
Logistic regression assessment of clinical parameters and peak postoperative biomarker levels (independent variables) with the development of postoperative in-hospital AKI (dependent variable)
| Odds ratio (95% CI) | P | Odds ratio (95% CI) | P | |
|---|---|---|---|---|
| Clinical model 1 | ||||
| Preoperative eGFR < 60 ml/min per 1.73 m2 | 1.27 (0.35–4.58) | 0.71 | ||
| Preoperative LVEF % | 0.92 (0.87–0.97) | 0.003 | ||
| BMI > 30 kg/m2 | 5.72 (1.77–18.52) | 0.004 | ||
| Clinical model 2 | ||||
| Cleveland Clinic score | 1.14 (0.91–1.42) | 0.27 | ||
| Biomarkers | Postoperative 6 h–POD 1 | Postoperative 6 h–POD 4 | ||
| Serum cystatin C | 3.81 (1.53–9.48) | 0.004 | 6.93 (2.59–18.59) | <0.001 |
| Urine NGAL/Cr | 1.17 (0.97–1.45) | 0.10 | 1.33 (1.05–1.67) | 0.016 |
| Urine KIM-1/Cr | 1.60 (1.06–2.42) | 0.026 | 2.23 (1.41–3.54) | <0.001 |
| Combination 1 Serum cystatin C + urine KIM-1/Cr | 6.20 (1.71–22.48) | 0.006 | 7.98 (1.98–25.97) | 0.003 |
| Combination 2 Serum cystatin C + urine KIM-1/Cr | 4.14 (1.50–11.43) | 0.006 | 7.14 (2.54–20.11) | <0.001 |
| Biomarkers adjusted by clinical model 1 | ||||
| Serum cystatin C | 4.09 (1.11–15.09) | 0.035 | 8.87 (2.34–33.58) | 0.001 |
| Urine NGAL/Cr | 1.22 (0.92–1.61) | 0.17 | 1.41 (1.03–1.94) | 0.030 |
| Urine KIM-1/Cr | 1.43 (0.87–2.36) | 0.16 | 2.07 (1.21–3.57) | 0.008 |
| Combination 1 Serum cystatin C + urine KIM-1/Cr | 5.32 (1.31–21.67) | 0.020 | 6.16 (1.51–25.05) | 0.011 |
| Combination 2 Serum cystatin C + urine KIM-1/Cr | 3.64 (1.01–13.15) | 0.049 | 4.97 (1.45–17.05) | 0.011 |
| Biomarkers adjusted by clinical model 2 | ||||
| Serum cystatin C | 4.78 (1.56–14.61) | 0.006 | 9.99 (3.12–32.06) | <0.001 |
| Urine NGAL/Cr | 1.16 (0.93–1.45) | 0.19 | 1.32 (1.02–1.69) | 0.033 |
| Urine KIM-1/Cr | 1.56 (1.02–2.38) | 0.041 | 2.22 (1.38–3.57) | 0.001 |
| Combination 1 Serum cystatin C + urine KIM-1/Cr | 6.02 (1.61–22.55) | 0.008 | 7.15 (1.89–27.00) | 0.004 |
| Combination 2 Serum cystatin C + urine KIM-1/Cr | 3.94 (1.35–11.44) | 0.012 | 7.03 (2.39–20.70) | <0.001 |
AKI, acute kidney injury; BMI, body mass index (kg/m2); CI, confidence interval; Cr, creatinine; eGFR, estimated glomerular filtration rate (ml/min per 1.73 m2); KIM-1, kidney injury molecule 1; LVEF, left ventricular ejection fraction (%); NGAL, neutrophil gelatinase-associated lipocalin; POD, postoperative day.
Clinical model 1 consisted of 3 preoperative clinical parameters that either were significantly associated with AKI in univariate analysis (preoperative LVEF% and BMI >30 kg/m2) or were clinically relevant for the model (preoperative eGFR <60 ml/min per 1.73 m2). Clinical model 2 was the Cleveland Clinic score validated for predicting AKI–renal replacement therapy following cardiac surgery.30 Duplets of biomarkers were combined as follows: (i) at least 1 biomarker above the cutoff value (combination 1), or (ii) both biomarkers above the cutoff value (combination 2). Biomarker data were log10 transformed and the odds ratios reported correspond to 2-fold higher levels in patients with versus without postoperative AKI.