Evaluation of the revised Schwartz creatinine-based glomerular filtration rate estimating equation in Black African children in KwaZulu-Natal, South Africa

Abstract

Background The use of serum creatinine equations for estimating glomerular filtration rate is well known in adults and children. We evaluated the revised Schwartz creatinine-based estimated glomerular filtration rate prediction equation in Black African children in KwaZulu-Natal, South Africa. Methods Review of medical records of all Black African patients aged 2-18 years old who have had glomerular filtration rate determined by intravenous Technetium-99 m-diethylene-triamine-pentaacetate, for the period 1 January 2010 to 31 December 2014 at the Inkosi Albert Luthuli Central Hospital, Durban, South Africa was performed. Estimated glomerular filtration rate result obtained using the revised Schwartz equation was compared to Technetium-99 m-diethylene-triamine-pentaacetate plasma clearance measured glomerular filtration rate. Accuracy of the estimated glomerular filtration rate equations within 10% (P) and 30% (P) of the measured glomerular filtration rate, sensitivity and specificity for predicting glomerular filtration rate < 60 mL/min/1.73 m and < 30 mL/min/1.73 m was determined. Results Results from 148 African children between 2 and 18 years old were analysed. P and P values were 16 and 49%, respectively. Sensitivity of 92.9% (95% CI: 80.5-85), specificity of 95.3 (95% CI: 89.3-98.5) and AUC of 0.96 (95% CI 0.92-0.99) were obtained for measured estimated glomerular filtration rate < 60 mL/min/1.73 m. Sensitivity of 88.2% (95% CI: 63.6-98.5), specificity of 90.8 (95% CI: 84.5-95.2) and area under the curve of 0.93 (95% CI 0.88-0.96) were obtained for measured estimated glomerular filtration rate < 30 mL/min/1.73 m. Conclusions The revised Schwartz equation did not meet the National Kidney Foundation Kidney Disease Outcomes Quality Initiative guidelines of 90% of estimated glomerular filtration rate results within 30% of measured glomerular filtration rate.