Abstract:

Abstract Objective: To compare the three equations of CKD-EPIscr, CKD-EPIcysc and CKD-EPIscr/cysc and evaluate the error of each equation in the clinical practice. Methodology: Seventy eight patients with CKD were enrolled into this study. The data of serum Cystatin C, creatinine and rGFR coming from 99mTc-DTPA renal dynamic imaging were collected. Three eGFR (eGFRscr, eGFRcysc and eGFRscr/cysc) were calculated by the equation of CKD-EPIscr、CKD-EPIcysc and CKD-EPIscr/cysc respectively. Errors (Δscr, Δcysc and Δscr/cysc) were compared with rGFR. Proportion-proportion plot, Pearson correlation analysis, Bland-Altman scatter diagram, Student’s t test and Chi-square test were performed for statistical analysis. Results: The data of Δscr, Δcysc and Δscr/cysc were shown by Gaussian distribution. Pearson correlation analysis and Bland-Altman scatter diagram suggested that the three eGFRs were correlated with rGFR significantly with the correlation coefficients of 0.832, 0.838 and 0.917 respectively. The percentage of points of Δscr, Δcysc and Δscr/cysc located in each 95% conformity boundary was 93.59%, 96.15% and 94.87% respectively. Student’s t test and chi-square test suggested that three 95% confidence intervals of the errors’ expectations were (-5.62, 1.22), （3,18, 10.50）and (-6.42, -1.59), and three 95% confidence intervals of the errors’ variances were (171.66, 324.18), (196.90, 371.85) and (85.55, 161.57). Further analysis by the 3 principle showed that Δscr∈(-59.63, 55.23), Δcysc∈(-54.67, 68.36) and Δscr/cysc∈(-44.55, 36.54) when each expectation and variance were critical values. Conclusion: Error range of CKD-EPIscr/cysc equation is minimum among the three CKD-EPI equations. CKD-EPIscr/cysc equation tends to be better than the CKD-EPIcysc equation and the CKD-EPIscr equation in calculating GFR in the clinical practice.