Acute kidney injury prediction using phosphorus as a simple biomarker in pediatric cardiac surgery patients

Background: Acute kidney injury (AKI) is a strong predictor of morbidity and mortality after cardiac surgery.Lack of valid early biomarkers for predicting AKI has hampered the ability to take therapeutic measures for preventive cause.It was not studied in this context and could be simple marker of AKI.Therefore, we tested role of serum phosphorus in prediction of AKI as a simple biomarker after cardiac surgery in pediatric population. Methodology: We prospectivelye valuated 113 children aged between 3mo-12yrs undergoing elective cardiac surgery. Serum creatinine and phosphorus were measured preoperatively and postoperatively at 24,48hrs.As per KDIGO (Kidney Disease Improving Global Outcome) criteria, patients were grouped into AKI and NON AKI onbasis of development of AKI within 48hrs postsurgery. Results: From 113 children included, 37 developed AKI.In AKI group, serum phosphorus increased significantly from 4.46±0.19baselineto 8.60±0.34 at 24 hrs postsurgery (p<0.0001). While serum creatinine increased frombaseline 0.28 to 0.41 at 24hrs (p<0.0001). Receiver Operating Characteristic Curve analysis showed that serum phosphorus at 24hrs,the area under the curve was 0.72 with sensitivity 80%, specificity 73.15% for a cut off value of 6.4mg/dl.Whereas serum phosphorus at 48hrs, the area under the curve was 0.90 with sensitivity85.29% and specificity87.34% for a cut off value of >5.2 mg/dl. Conclusion: Serum phosphorus can be a simple biomarker as early as 24hrs for early prediction of AKI in paediatric cardiac surgery.