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Abstract: TH-PO031

Using Kinetic Glomerular Filtration Rate to Predict AKI

Session Information

Category: Acute Kidney Injury

  • 101 AKI: Epidemiology, Risk Factors, and Prevention

Authors

  • Claure-Del Granado, Rolando, Hospital Obrero #2 - C.N.S.; Universidad Mayor de San Simon, School of Medicine, Cochabamba, Bolivia, Plurinational State of
  • Sanchez, Cristian G., Hospital Obrero #2 - C.N.S.; Universidad Mayor de San Simon, School of Medicine, Cochabamba, Bolivia, Plurinational State of
  • Bouchard, Josee, Hopital du Sacre-Coeur de Montreal, Montreal, Quebec, Canada
  • Mehta, Ravindra L., University of California San Diego Medical Center, La Jolla, California, United States
Background

Monitoring renal function changes during critical illness is difficult as current MDRD and CKD-EPI GFR estimating equations usually under or overestimate renal function during an episode of acute kidney injury (AKI). The kinetic glomerular filtration rate (KeGFR) equation (J Am Soc Nephrol 2013; 24: 877–888) has been developed to better evaluate rapid changes in renal function. We hypothesized that changes in KeGFR would predict the development of AKI in critically ill patients.

Methods

We prospectively evaluated 208 patients admitted to our general ICU. Serum creatinine (sCr) was measured daily for 7 days. KeGFR was calculated from the change in consecutive values of sCr (ICU baseline sCr and 24 h ICU sCr). In patientswith no baseline sCr available we back calculated sCr using MDRD equation (for an eGFR = 75 ml/m/1.73m2). Patients diagnosed with AKI in the first 24 hours after ICU admission according to the KDIGO definition were excluded. AKI was defined as an increase of sCr value 1.5 times the baseline value or 0.3 mg/dl above the baseline within 48 hours to 7 days after ICU admission. The predictive performance of KeGFR was assessed by the receiver operator characteristic analysis to determine the area under the curve (AUC).

Results

From 208 patients enrolled in the study 98 patients developed AKI (47 %). Age, baseline serum creatinine, and eGFR (CKD-EPI) were not different between patients with and without AKI. At 24 h post ICU admission AKI patients had lower KeGFR (47.7 ml/m vs. 81.1 ml/m; p < 0.0001); at this time point KeGFR predicted AKI with an AUC of 0.778 (95% CI 0.689 - 0.867; p < 0.001). A KeGFR reduction from a baseline eGFR (ICU admission) ≥ 22.6% had a sensitivity of 95.3% and a specificity of 87.5% for predicting subsequent AKI development within 48 h and 7 days of ICU admission with an AUC of 0.969 (95% CI 0.932 – 1.000; p < 0.001). This reduction in KeGFR percentage from a baseline eGFR had an odds ratio of 4.5 (95% CI 1.675 – 12.090; p = 0.002) for subsequent development of AKI after 48 h of ICU admission.

Conclusion

The use of KeGFR accounts for non-steady state conditions and could improve clinical risk prediction models for AKI development in the ICU. sCr measurements, which can be obtained at modest cost, remain useful to guide early management of AKI if performed frequently.