[Comparison between CKD-EPI and MDRD-equations to estimate glomerular filtration rate in chronic kidney disease patients]. / Comparación entre las ecuaciones CKD-EPI y MDRD para la estimación del filtrado glomerular en pacientes con enfermedad renal crónica.

The MDRD equation to estimate glomerular filtration rate (GFR) is the most widely used strategy to assess chronic kidney disease. Nonetheless, for the individual patient the true GFR can be underestimated with the risk of diagnosing a more elevated CKD stage. This novel CKD-EPI equation would improve accuracy and precision of estimations, and several authors recommend this new equation replace the former. In our country there is only a limited registration of these comparisons performed on a large number of patients. Therefore, our aim was to develop a comparison in a wide cohort of patients. The concordance between both equations to assign the GFR stages was determined by using the MDRD formula as a reference. The mean difference of GFR obtained with both equations as well as the Bland-Altman analysis were calculated. A cohort of 9319 individuals, of whom 67% were females, aged 58 ± 20 years, with serum creatinine values of 1.6 ± 1.03 mg/dl, was studied. In the whole group, CKD-EPI displayed an average GFR 0.61 ml/min/1.73 m2 larger than MDRD (p: NS). For CKD stages 2 and 3A the mean estimated GFR difference was 6.95 ± 4.76 and 3.21 ± 3.31, while the concordance was 81 and 74% respectively. The percentage of patients with GFR < 60 ml/min/1.73 m2, decreased from 76.3% with the former equation to 70.1% with the latter. The novel equation CKD-EPI reduces the number of patients with GFR values lower than 60 ml/min/1.73 m2 and consequently assigns a higher GFR stage to a considerable quantity of individuals.

Comparación entre las ecuaciones CKD-EPI y MDRD para la estimación del filtrado glomerular en pacientes con enfermedad renal crónica / Comparison between CKD-EPI and MDRD-equations to estimate glomerular filtration rate in chronic kidney disease patients

La ecuación MDRD para la estimación del índice de filtrado glomerular (IFG), es la estrategia más utilizada para evaluar pacientes con enfermedad renal crónica (ERC). Sin embargo, puede subestimar el IFG con el riesgo de asignar al paciente a estadios más avanzados de ERC. La nueva ecuación CKD-EPI, mejoraría la exactitud y precisión de las estimaciones. Sus autores sugieren que reemplace a la anterior. No habiendo comparaciones de estas ecuaciones aplicadas en un gran número de pacientes en nuestro país, nuestro objetivo fue realizarla en una amplia cohorte de pacientes. Se evaluó la concordancia de asignación en estadios de ERC entre ambas ecuaciones, tomando como referencia los datos surgidos de MDRD. Se calculó la media de las diferencias de los IFG obtenidos empleando ambas ecuaciones y se aplicó el análisis estadístico de Bland-Altman. Se estudió una cohorte de 9 319 pacientes con una media de creatinina sérica de 1.60 ± 1.03 mg/dl, 67% de sexo femenino y edad media 58 ± 20 años. En el grupo total, CKD-EPI presentó una media de IFG 0.61 ml/min/1.73 m² mayor que MDRD (p: NS). En los estadios 2 y 3A las medias del IFG fueron respectivamente 6.95 ± 4.76 y 3.21 ± 3.31, y la concordancia de 81 y 74%. El porcentaje de pacientes con un IFG menor de 60 ml/min/1.73 m², se redujo de 76.3% (MDRD) a 70.1% (CKD-EPI). Por lo tanto, la nueva ecuación CKD-EPI disminuye el número de pacientes con IFG debajo de 60 ml/min/1.73 m² y asigna estadios de IFG más elevado a un número mayor de pacientes.

The MDRD equation to estimate glomerular filtration rate (GFR) is the most widely used strategy to assess chronic kidney disease. Nonetheless, for the individual patient the true GFR can be underestimated with the risk of diagnosing a more elevated CKD stage. This novel CKD-EPI equation would improve accuracy and precision of estimations, and several authors recommend this new equation replace the former. In our country there is only a limited registration of these comparisons performed on a large number of patients. Therefore, our aim was to develop a comparison in a wide cohort of patients. The concordance between both equations to assign the GFR stages was determined by using the MDRD formula as a reference. The mean difference of GFR obtained with both equations as well as the Bland-Altman analysis were calculated. A cohort of 9 319 individuals, of whom 67% were females, aged 58 ± 20 years, with serum creatinine values of 1.6 ± 1.03 mg/dl, was studied. In the whole group, CKD-EPI displayed an average GFR 0.61 ml/min/1.73 m² larger than MDRD (p: NS). For CKD stages 2 and 3A the mean estimated GFR difference was 6.95 ± 4.76 and 3.21 ± 3.31, while the concordance was 81 and 74% respectively. The percentage of patients with GFR < 60 ml/min/1.73 m², decreased from 76.3% with the former equation to 70.1% with the latter. The novel equation CKD-EPI reduces the number of patients with GFR values lower than 60 ml/min/1.73 m² and consequently assigns a higher GFR stage to a considerable quantity of individuals.

Elimination and clearance of pamidronate by haemodialysis.

Pamidronate (APD), a third-generation bisphosphonate, has proven to be useful in haemodialysis (HD) patients with ectopic calcifications and hypercalcaemia. Little is known about bisphosphonates clearance in patients undergoing HD. The authors' main objective was to study HD removal and clearance of APD. In total, 23 HD-requiring anuric end-stage renal disease (ESRD) adult individuals (12 men) aged 61.7 +/- 13 (mean +/- SD) years were admitted into the study. APD clearance and elimination were evaluated by (99m)Technetium APD (half-life 6 h). In total, 1 mg of labelled APD was injected via the arteriovenous graft prior to the start of HD. Blood samples were then drawn from the arterial (predialyser) and venous (postdialyser) lines of the extracorporeal circuit 2 h after the HD onset. In a subgroup of patients (n: 15) the dialysate was collected and quantified during the three initial HD hours. Venous APD concentrations (postdialyser) were 72 + 7% of arterial (predialyser) concentrations. Mean APD clearance was 69.3 + 16.6 mL/min, and mean APD extraction during dialysis session was 31.6 + 10.1%. In the present study involving HD-requiring anuric ESRD patients APD was successfully eliminated by HD. At the dose administered here none of the participants reported adverse events. APD is a potentially useful drug to be administered to HD-requiring ESRD patients, the understanding of its removal during HD as well as its dialytic clearance allows for a safer management of a drug that is usually eliminated by renal excretion.