Francesco Gaetano Casino1,2, Javier Deira3, Miguel A Suárez4, José Aguilar3, Giovanni Santarsia5, Carlo Basile6,7. 1. Dialysis Centre SM2, Policoro, Italy. 2. Division of Nephrology, Miulli General Hospital, Strada Provinciale Santeramo, 70121, Acquaviva delle Fonti, Puglia, Italy. 3. Division of Nephrology, San Pedro de Alcantara Hospital, Cáceres, Spain. 4. Division of Nephrology, Virgen del Puerto Hospital, Cáceres, Spain. 5. Division of Nephrology, Ospedale Madonna Delle Grazie, Matera, Italy. 6. Division of Nephrology, Miulli General Hospital, Strada Provinciale Santeramo, 70121, Acquaviva delle Fonti, Puglia, Italy. basile.miulli@libero.it. 7. Associazione Nefrologica Gabriella Sebastio, Martina Franca, Italy. basile.miulli@libero.it.
Abstract
INTRODUCTION: The haemodialysis (HD) dose, as expressed by Kt/V urea, is currently routinely estimated with the second generation Daugirdas (D2) equation (Daugirdas in J Am Soc Nephrol 4:1205-1213, 1993). This equation, initially devised for a thrice-weekly schedule, was modified to be used for all dialysis schedules (Daugirdas et al. in Nephrol Dial Transplant 28:2156-2160, 2013), by adopting a variable factor that adjusts for the urea generation (GFAC) over the preceding inter-dialysis interval (PIDI, days). This factor was set at 0.008 for the mid-week session of the standard thrice-weekly HD schedule. In theory, by setting PIDI = 7, one could get GFAC = 0.0025, to be used in patients on the once-weekly (1HD/wk) schedule, but actually this has never been tested. Moreover, GFAC was derived not taking into account the residual kidney urea clearance (Kru). Aim of the present study was to provide a specific value of GFAC for patients on a once-weekly hemodialysis schedule. SUBJECTS AND METHODS: The equation to predict GFAC (GFAC-1) in the 1HD/wk schedule was established in a group of 80 historical Italian patients (group 1) and validated in a group of 100 historical Spanish patients (group 2), by comparing the Kt/V computed using GFAC-1 (Kt/VGFAC-1) with the reference Kt/V (Kt/VSS) values, as computed with the web-based Solute-Solver software (SS) (Daugirdas et al. in Am J Kidney Dis 54:798-809, 2009). Three more sets of Kt/V (Kt/V0.008, Kt/V0.0025 and Kt/V0.0035) values were computed using the GFAC of the original D2 equation (0.008), the GFAC predicted by PIDI/7 (0.0025) and the mean observed GFAC-1 (0.0035), respectively. They were compared with the reference Kt/VSS values. RESULTS: The predicting equation obtained from group 1 was: GFAC-1 = 0.0022 + 0.0105 × Kru/V (R2 = 0.93). Mean Kt/VSS in the group 2 was 1.54 ± 0.29 SD (N = 500 HD sessions). The mean percent differences for Kt/V0.008, Kt/V0.0025, Kt/VGFAC-1, and Kt/V0.0035 were 5.1 ± 1.0%, - 1.4 ± 0.7%, 0.0 ± 0.3%, - 0.3 ± 0.7%, respectively. No statistically significant difference was found between Kt/V values, except for Kt/V0.008. CONCLUSION: A linear relationship was found between GFAC and Kru/V in patients on the 1HD/wk schedule. Such a relationship is able to improve the "second generation Daugirdas equation" for an accurate estimate of the single pool Kt/V in this setting. However, a simple replacement in the D2 equation of 0.008 with the mean observed GFAC (0.0035) could suffice in the clinical practice.
INTRODUCTION: The haemodialysis (HD) dose, as expressed by Kt/V urea, is currently routinely estimated with the second generation Daugirdas (D2) equation (Daugirdas in J Am Soc Nephrol 4:1205-1213, 1993). This equation, initially devised for a thrice-weekly schedule, was modified to be used for all dialysis schedules (Daugirdas et al. in Nephrol Dial Transplant 28:2156-2160, 2013), by adopting a variable factor that adjusts for the urea generation (GFAC) over the preceding inter-dialysis interval (PIDI, days). This factor was set at 0.008 for the mid-week session of the standard thrice-weekly HD schedule. In theory, by setting PIDI = 7, one could get GFAC = 0.0025, to be used in patients on the once-weekly (1HD/wk) schedule, but actually this has never been tested. Moreover, GFAC was derived not taking into account the residual kidney urea clearance (Kru). Aim of the present study was to provide a specific value of GFAC for patients on a once-weekly hemodialysis schedule. SUBJECTS AND METHODS: The equation to predict GFAC (GFAC-1) in the 1HD/wk schedule was established in a group of 80 historical Italian patients (group 1) and validated in a group of 100 historical Spanish patients (group 2), by comparing the Kt/V computed using GFAC-1 (Kt/VGFAC-1) with the reference Kt/V (Kt/VSS) values, as computed with the web-based Solute-Solver software (SS) (Daugirdas et al. in Am J Kidney Dis 54:798-809, 2009). Three more sets of Kt/V (Kt/V0.008, Kt/V0.0025 and Kt/V0.0035) values were computed using the GFAC of the original D2 equation (0.008), the GFAC predicted by PIDI/7 (0.0025) and the mean observed GFAC-1 (0.0035), respectively. They were compared with the reference Kt/VSS values. RESULTS: The predicting equation obtained from group 1 was: GFAC-1 = 0.0022 + 0.0105 × Kru/V (R2 = 0.93). Mean Kt/VSS in the group 2 was 1.54 ± 0.29 SD (N = 500 HD sessions). The mean percent differences for Kt/V0.008, Kt/V0.0025, Kt/VGFAC-1, and Kt/V0.0035 were 5.1 ± 1.0%, - 1.4 ± 0.7%, 0.0 ± 0.3%, - 0.3 ± 0.7%, respectively. No statistically significant difference was found between Kt/V values, except for Kt/V0.008. CONCLUSION: A linear relationship was found between GFAC and Kru/V in patients on the 1HD/wk schedule. Such a relationship is able to improve the "second generation Daugirdas equation" for an accurate estimate of the single pool Kt/V in this setting. However, a simple replacement in the D2 equation of 0.008 with the mean observed GFAC (0.0035) could suffice in the clinical practice.
Authors: Francesco G Casino; Carlo Basile; Dimitrios Kirmizis; Mehmet Kanbay; Frank van der Sande; Daniel Schneditz; Sandip Mitra; Andrew Davenport; Loreto Gesualdo Journal: Nephrol Dial Transplant Date: 2020-12-22 Impact factor: 5.992
Authors: Milagros Fernández-Lucas; José L Teruel-Briones; Antonio Gomis-Couto; Javier Villacorta-Pérez; Carlos Quereda-Rodríguez-Navarro Journal: Nefrologia Date: 2012 Impact factor: 2.033
Authors: Javier Deira; Miguel A Suárez; Francisca López; Emilio García-Cabrera; Antonio Gascón; Eduardo Torregrosa; Giannina E García; Jorge Huertas; Jose C de la Flor; Suleya Puello; Jonathan Gómez-Raja; Jesús Grande; José L Lerma; Carlos Corradino; Carlos Musso; Manuel Ramos; Jesús Martín; Carlo Basile; Francesco G Casino Journal: BMC Nephrol Date: 2019-01-09 Impact factor: 2.388