Serum (inhibition C And Estimated Glomerular Filtration Rate Formula Application In Senile Renal Function Evaluation Research

Objective: This study aimed to evaluate the applicability of a selection of glomerularfiltration rate (GFR) estimating equations based on serum creatinine (SCr) and serumcystatin C in a Chinese population.Methods: Estimated GFR values from ten equations were compared with referenceGFR (rGFR) from the99mTc-DTPA renal dynamic imaging method.Results: The study enrolled569Chinese participants (41.5%women,53.5±16.9yr,range19-92yr), with mean rGFR74.80±26.10(range9.8-146.8ml/min/1.73m2).Bland-Altman analysis illustrated that the95%agreement limits of all the equationssurpassed the acceptable tolerance (less than60ml/min/1.73m2), of which theMacIsaac equation was the closest one, reaching at71.7ml/min/1.73m2. Linearregression analysis also demonstrated a consistent result. When assessed in allparticipants, the accuracy of the six equations reached and exceeded the acceptablelevel (≥70%), of which the Shanghai and MacIsaac equations gained more accuracythan others. When compared in sub-groups, the Chronic Kidney DiseaseEpidemiology Collaboration (CKD-EPI), MacIsaac and Cockcroft-Gault (CG)equations were optimal for rGFR≥90ml/min/1.73m2,30-89ml/min/1.73m2and<30ml/min/1.73m2stage, respectively.Conclusions: The results demonstrated that further improvement is needed for theselected10equations. Not all the cystatin C equations were superior to SCr equations.They have their own applicability at various GFR levels. At present, the CKD-EPIequation, MacIsaac equation and CG equations may be applied to evaluate GFR in normal, mild to moderate and severe kidney function, respectively. Background：Serum cystatin C has been recognized as a surrogate marker to serumcreatinine (SCr). However, whether cystatin C and cystatin C-based glomerularfiltration rate (GFR) formulae exit various diagnostic values in non-elderly andelderly subjects has rarely discussed.Methods：99mTc-DTPA renal dynamic imaging method was measured as referenceGFR (rGFR). Nine GFR formulae were calculated to predict estimated GFR (eGFR).Results: A total of534Chinese participants were enrolled. Cystatin C had betterdiagnostic value than SCr. The superiority of cystatin C was more distinctly observedin the elderly. Alliance of cystatin C and SCr performed similar diagnostic values ascystatin C alone (P>0.05). Compared with sole markers, GFR prediction formulaeimproved the accuracy. Each formula had its own characteristics and applicability.Most formulae predicted higher accuracy in the elderly than they in the non-elderly.In CKD1stage, the CKD-EPI formula had the least bias and the highest accuracy forthe non-elderly, while, the Hojs and Ma formula performed the best for the elderly. Inthe CKD2-3stages, the MacIsaac formula predicted the most accurate eGFR. In theCKD4-5stage, it is the CG formula estimated the closest to the rGFR.Conclusions: Cystatin C could be superior to SCr, particularly in the elderly;however, cystatin C-formula and SCr-formula may possess its own applicability invarious CKD stages and age groups. At present, it is not the time to say cystatin C-formulae are superior to SCr-formulae. Background: The present glomerular filtration rate (GFR) estimating equations wereproved unsuitable for Chinese population. Of them, the Chronic KidneyDisease-Epidemiology (CKD-EPI), Modification of Diet in Renal Disease (MDRD)and MacIsaac equations predicted relatively accurate. Thus, this study was designedto modify the three equations for Chinese populations.Methods:99mTc-DTPA renal dynamic imaging was measured as the reference GFR(rGFR). Mathematical algorithms, including the hill-climbing and the simulatedannealing (SA) algorithms were applied to modify the three equations. Root meansquare error (RMSE) and the proportion of estimated GFR (eGFR) deviating within30%of rGFR (P30) were used to measure the improvement in accuracy of theseequations before and after their modification.Results: A total of318patients (rGFR77.58±24.87ml/min/1.73m2, age52.95±17.13yr) were enrolled. After modification, RMSE of each equation reduced in variousdegrees with P30of each equation increasing. RMSE calculated by the SA algorithmswas greater than that by the hill-climbing algorithms. The global optimum locationfrom the hill-climbing algorithms was similar with that from the SA algorithms.Conclusions: Mathematical algorithms could be a fine tool to modify the GFRequations. The accuracy of all three modified GFR equations was improved thanbefore, of which, the modified CKD-EPI might be the best recommendation.