A New Method For Assessing Glomerular Filtration Rate In The Elderly

Background:Glomerular filtration rate(GFR)is the essential parameter to diagnose and risk classification of chronic kidney disease(CKD),as well as for dose adjusting and preoperative preparation.Equations to predict GFR now have applied worldwide,and successively updating.With increasing accuracy,GFR equations were attached more importance.In recent years,GFR equations have individual target population,some for children,some for adults.However,our previous studies proved that these adults equations were not suitable for Chinese elderly.A new equation based on full age spectrum(FAS)in Europe population was established in 2016.Whether this FAS serial equations will estimate more accurate GFR for Chinese elderly is not verified.The present study was aimed to assess the applicability of the FAS serial equations.Methods:We use ^99mTc-DTPA renal dynamic imaging as a reference GFR(r GFR),particle-enhanced nephelometric immunoassay to determine serum cystatin C(Scys)and oxidase method to examine serum creatinine(Scr).Then,compare the accuracy of CKD-EPI serial equation and FAS serial equation in non-elderly subjects(<60years)and elderly subjects,in virtue of parameters,such as bias,inter quartile range(IQR),P₃₀and root mean square error(RMSE).Results:A total of 1329 subjects from the First Affiliated Hospital of Nanjing Medical University,the Third Affliated Hospital of Sun Yat-sen University,the Affliated Wuxi No.2 Hospital of Nanjing Medical University and the Fourth Hospital of Jilin University were included in this study.The median age was 70 years old in the elderly group.And the median r GFR was 51.79ml/min/1.73m²,which was was significantly decreased,compared to non-elderly group.The relationship analysis showed the two serial equations were closely to the standard method.The relation value in elderly group is slightly higher than that in non-elderly group.And The relation value in Scr-Scys combination equations is higher than that in solo Scys equations.Compared to Scys-based equations,the Scr-Scys based equations performed better,both in bias,P₃₀and in IQR,RMSE.However,the FAS serial equations did not show significant superior performance to the CKD-EPI serial equations.Conclusion:The FAS serial equations predict similar accurate GFR to the CKD-EPI equations.The causes still includes race,GFR standard and subjects,as before.It is necessary to establish a new GFR estimation model for Chines elderly population.