External Validation of the XXXX Risk Equation and Re-Calibration with Addition of Ultrasound Parameters.

@entity177 @entity1 @entity454
BACKGROUND AND OBJECTIVES: Progression of CKD toward @entity454 is heterogeneous. The @entity177 Risk Equation (KFRE) was developed to identify CKD @entity1 at high risk of @entity454 . We aimed to externally validate KFRE and to test whether the addition of predefined Duplex ultrasound markers - renal resistive index (RRI) or difference of resistive indices in spleen and kidney (DI-RISK) - improved @entity454 prediction. DESIGN, SETTING, @entity1 , _ MEASUREMENTS: The prospective Cardiovascular and Renal Outcome in CKD 2-4 @entity1 -The Fourth Homburg evaluation (CARE FOR HOMe) study recruits CKD stage G2-G4 @entity1 referred to a tertiary referral center for nephrologic care. Four hundred three CARE FOR HOMe @entity1 enrolled between 2008 and 2012 had available RRI measurements at study inclusion; they were subsequently followed for a mean of 4.4  1.6  years. This subcohort was used to validate KFRE and to assess the added value of the ultrasound markers (new models KFRE+RRI and KFRE+DI-RISK). Model performance was assessed by log-likelihood ratio test, c-statistic, integrated discrimination improvement metrics (for study @entity1 without subsequent @entity454 [IDI No @entity454 ] and for @entity1 with @entity454 [IDI @entity454 ]), and calibration plots. If either new model improved on KFRE, we determined to validate it in an independent cohort of 162 CKD @entity1 . RESULTS: KFRE predicted @entity454 in CARE FOR HOMe @entity1 with a c-statistic of 0.91 (95% confidence interval, 0.83 to 0.99). Adding RRI improved the KFRE model (P<0.001), and the KFRE+RRI model was well calibrated; however, the c-statistic (0.91 [0.83-1.00]) was similar, and overall sensitivity (IDI No @entity454 =0.05 [0.00-0.10]) or overall specificity (IDI @entity454 =0.00 [0.00-0.01]) did not improve. Adding DI-RISK did not improve the KRFE model. In the external validation cohort, we confirmed that the KFRE+RRI model did not outperform KFRE. CONCLUSIONS: Routine Duplex examinations among CKD @entity1 did not improve risk prediction for progression to @entity454 beyond a validated equation.
