A Clinical Score to Predict Severe Acute Kidney Injury in Chinese Patients after Cardiac Surgery.

BACKGROUND/AIMS: Cardiac surgery-associated severe acute kidney injury (SAKI) is associated with high mortality and poor quality of life. A prognostic score for SAKI may enable prevention of complications.

METHODS

This observational study of 2,552 patients undergoing cardiac surgery from January 2006 to December 2011 in our institution established associations between predictor variables and postoperative SAKI from a cohort of 1,692 patients and developed a clinical score that was assessed in a validation cohort of 860 patients.

RESULTS

Postoperative SAKI occurred in 262 -patients (10.3%). We identified 7 independent and significant risk factors in the derivation model (adjusted OR 95% CI): age ≥81 years (vs. age < 40 years, 4.30, 1.52-12.21), age 61-80 years (vs. age < 40 years, 2.84, 1.24-6.52), age 41-60 years (vs. age < 40 years, 1.62, 0.68-3.87), hypertension (1.65, 1.13-2.39), previous cardiac surgery (3.62, 1.27-10.32), -hyperuricemia (2.02, 1.40-2.92), prolonged operation time (1.32, 1.17-1.48), postoperative central venous pressure < 6 mm H2O (3.53, 2.38-5.23), and low postoperative cardiac output (4.78, 2.97-7.69). The 7-variable risk prediction model had acceptable performance characteristics in the validation cohort (C statistic 0.80, 95% CI 0.74-0.85). The difference in the C statistic was 0.21 (95% CI 0.12-0.29, p < 0.001) compared with the Cleveland Clinic score.

CONCLUSION

We developed and validated a practical risk prediction model for SAKI after cardiac surgery based on routinely available perioperative clinical and laboratory data. The prediction model can be easily applied at the bedside and provides a simple and interpretable estimation of risk.