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Abstract: SA-PO709

The Accuracy of Equations That Estimate Glomerular Filtration Rate Compared with Measured Creatinine Clearance in Critically Ill Patients

Session Information

Category: Pathology and Lab Medicine

  • 1602 Pathology and Lab Medicine: Clinical

Authors

  • Alsadhan, Abdulmajeed, King Abdulaziz Medical City-Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
  • Al-Dorzi, Hasan M., King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
  • Almozaini, Ayman Saleh, King Abdulaziz Medical City-Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
  • Alamri, Ali, King Abdulaziz Medical City-Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
  • Tamim, Hani, American University of Beirut, Beirut, Lebanon
  • Alswaidan, Lolowa, King Abdulaziz Medical City-Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
  • Arabi, Yaseen M., King Saud Bin Abdulaziz University for Health Sciences, King Abdulaziz Medical City, Riyadh, Saudi Arabia
Background

The accuracy of glomerular filtration rate estimates has been questioned. This study compared estimates of GFR by commonly used equations with creatinine clearance measured by 24-hour urine collection in critically ill patients.

Methods

This sub-study of the PermiT trial included the patients enrolled at KAMC-Riyadh who had 24-hr urine collection. We estimated GFR using the Cockroft–Gault (CG), Modification of Diet in Renal Disease(MDRD4-MDRD6) and Chronic Kidney Disease Epidemiology Collaboration(CKD-EPI) equations.For the CG equation, we entered actual weight in one calculation(CG actual-wt), and for BMI ≥30 kg/m2, the ideal body weight and the adjusted body weight in two calculations.

Results

The cohort consisted of 238 patients (age 45.2±20.2 years, DM 31.9%, CKD 2.9%, APACHE II 20.3±8.1, mechanical ventilation 98.7% and serum Cr 214±128 micromol/L). The measured CrCl24h-urine was 117.0±75.0 ml/min.The correlations between the different formulae were all significant (p<0.0001).

Conclusion

There was a modest correlation between the formulae estimating GFR with CrCl24hr-urine. CGactual-wt had the best correlation. Strength of correlation changed within the different ranges of CrCl24h-urine.

 Estimated GFR(ml/min)Correlation(r) with CrCl(24h-urine)
CG (Actual-wt)138.3 67.20.80
CG(Ideal-wt)121.0 62.40.74
CG(Adjusted-wt)127.9 62.40.78
MDRD-4116.8 54.10.66
MDRD-6109.2 51.00.65
CKD-EPI103.5 39.50.71