Validation of the kidney failure risk equation in a Portuguese cohort / Validación de la ecuación de riesgo de insuficiencia renal en una cohorte portuguesa

Introduction: In chronic kidney disease (CKD) patients, the risk of kidney replacement therapy (KRT) is highly variable. In 2011, Tangri et al. developed the kidney failure risk equations (KFRE) to predict the 2 and 5-year probability of requiring kidney replacement therapy (KRT). The KFRE is an easily calculated 4-variable equation which has been extensively validated in multiple cohorts. The aim of this study was to validate this risk score in a Portuguese cohort. Methods: We conducted a retrospective analysis of CKD patients stage 3–5 referred for nephrology consult at Centro Hospitalar Universitário Lisboa Norte during the first 6 months of 2018. Age, gender, estimated glomerular filtration rate (eGFR) and albuminuria were assessed. The 4-variable kidney failure risk equation (KFRE) calibrated to a non-North American population was calculated. Requirement of KRT was assessed in a 2-year follow-up. We assessed the Cox logistic regression method of the KFRE to predict KRT requirement and the discriminatory ability was determined using the receiver operating characteristic (ROC) curve. A cut-off value was defined as that with the highest validity. Results: 360 patients were included and 54.4% were male. Mean age was 74.9±12.2 years, serum creatinine was 1.97±0.84mg/dL, eGFR was 33.4±12.13ml/min/1.73m2 and albuminuria was 571.1±848.3mg/g. Mean calculated risk score was 6.2±11.2%. Twenty-three patients required KRT (6.4%) in the two-year follow-up. The hazard ratio was 1.1 [95% CI (1.06–1.12), p<0.001] for the 2-year risk of KRT. The KFRE predicted progression to KRT requirement with an auROC of 0.903, [95% CI (0.86–0.95), p<0.001], with a sensitivity 91.3% and specificity of 71.8%. (AU)

Introducción: En pacientes con enfermedad renal crónica (ERC), el riesgo de la terapia de reemplazo renal (TRR) es muy variable. En 2011, Tangri et al. desarrollaron las ecuaciones de riesgo de insuficiencia renal (KFRE) para predecir la probabilidad de 2 y 5años de requerir terapia de reemplazo renal (KRT). El KFRE es una ecuación de 4 variables de fácil cálculo que ha sido ampliamente validada en múltiples cohortes. El objetivo de este estudio fue validar esta puntuación de riesgo en una cohorte portuguesa. Métodos: Se realizó un análisis retrospectivo de pacientes con ERC estadio 3-5 remitidos para consulta de Nefrología en el Centro Hospitalario Universitário Lisboa Norte durante los primeros 6meses de 2018. Se evaluaron la edad, el sexo, el filtrado glomerular estimado (TFGe) y la albuminuria. Se calculó la ecuación de riesgo de insuficiencia renal (KFRE) de 4 variables calibrada para una población no norteamericana. La necesidad de KRT se evaluó en un seguimiento de 2años. Evaluamos el método de regresión logística de Cox del KFRE para predecir el requisito de KRT, y la capacidad discriminatoria se determinó utilizando la curva de característica operativa del receptor (ROC). Se definió como valor de corte el de mayor validez. Resultados: Se incluyeron 360 pacientes, y el 54,4% eran varones. La edad media fue de 74,9±12,2 años, la creatinina sérica de 1,97±0,84mg/dl, la TFGe de 33,4±12,13ml/min/1,73m2 y la albuminuria de 571,1±848,3mg/g. La puntuación de riesgo media calculada fue de 6,2±11,2%. Veintitrés pacientes requirieron KRT (6,4%) en los 2años de seguimiento. El cociente de riesgos instantáneos fue de 1,1 (IC del 95%: 1,06-1,12; p<0,001) para el riesgo de 2años de KRT. El KFRE predijo la progresión al requerimiento de KRT con un auROC de 0,903 (p<0,001; IC del 95%: 0,86-0,95), con una sensibilidad del 91,3% y una especificidad del 71,8%. (AU)

Validation of the kidney failure risk equation in a Portuguese cohort.

INTRODUCTION: In chronic kidney disease (CKD) patients, the risk of kidney replacement therapy (KRT) is highly variable. In 2011, Tangri et al. developed the kidney failure risk equations (KFRE) to predict the 2 and 5-year probability of requiring kidney replacement therapy (KRT). The KFRE is an easily calculated 4-variable equation which has been extensively validated in multiple cohorts. The aim of this study was to validate this risk score in a Portuguese cohort. METHODS: We conducted a retrospective analysis of CKD patients stage 3-5 referred for nephrology consult at Centro Hospitalar Universitário Lisboa Norte during the first 6 months of 2018. Age, gender, estimated glomerular filtration rate (eGFR) and albuminuria were assessed. The 4-variable kidney failure risk equation (KFRE) calibrated to a non-North American population was calculated. Requirement of KRT was assessed in a 2-year follow-up. We assessed the Cox logistic regression method of the KFRE to predict KRT requirement and the discriminatory ability was determined using the receiver operating characteristic (ROC) curve. A cut-off value was defined as that with the highest validity. RESULTS: 360 patients were included and 54.4% were male. Mean age was 74.9±12.2 years, serum creatinine was 1.97±0.84mg/dL, eGFR was 33.4±12.13ml/min/1.73m2 and albuminuria was 571.1±848.3mg/g. Mean calculated risk score was 6.2±11.2%. Twenty-three patients required KRT (6.4%) in the two-year follow-up. The hazard ratio was 1.1 [95% CI (1.06-1.12), p<0.001] for the 2-year risk of KRT. The KFRE predicted progression to KRT requirement with an auROC of 0.903, [95% CI (0.86-0.95), p<0.001], with a sensitivity 91.3% and specificity of 71.8%. The optimal KFRE cut-off was >4.5% for 2-year nephrologist referral, with an hazard ratio of HR 26.7 [95% CI (6.15-116.3), p<0.001] for 2-year risk of KRT requirement. DISCUSSION: We have independently externally validated the 2-year KFRE and shown that it has excellent discrimination. The KFRE should be incorporated in clinical care of patients with CKD to improve patient-clinician dialogue and provide guidance on timing of referral for nephrology evaluation and planning for dialysis access.