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Patients with chronic kidney disease (CKD) stage 5D suffer from the accumulation of uremic toxins. The treatment with hemodiafiltration (HDF) demonstrates the highest capacity for removing solutes with small and middle molecular weight, as well as improving mortality. While exercise has been proven as an adjunct therapy in patients on maintenance hemodialysis, little is known about the exercise influence in maintenance HDF programs. Objectives: Assess the impact of physical exercise in the performance and in patient-reported outcomes in patients on maintenance HDF regimen.
A retrospective observational study in a cohort of CKD 5D patients at Fenix Nephrology group from 2021 until 2023. We assessed the patients at the start of the exercise program and after six months of rehabilitation. Physical tests analyzed included the step-test for endurance, handgrip and one-repetition maximum (1RM) for muscle strength. The Kidney Disease Quality of Life Short Form (KDQOL-SF) evaluated patient-reported outcomes. Kt/Vurea and the urea reduction ratio (URR) were surrogates for HDF adequacy. The patients carried out twice weekly aerobic exercises at 70% of the maximum heart rate during the step test, and resistance exercises at 60% of 1RM.
Data from all 234 patients were obtained from electronic health records. Of those, 81 were not on the exercise program. From the remaining 153 patients, we excluded 64. The reasons for exclusion comprised patients who underwent kidney transplantation during their participation in the exercise program (n=12), incomplete data (n=41), execution of less than 80% of the scheduled exercise sessions (n=11). We included in our final analysis data from 89 patients (55±15 years old, most were male (n=52; 58.4%). Mean renal replacement therapy was 9±7 years and mean HDF was 5±4 years. There were no reported serious complications during the exercise program and no sessions had to be interrupted due to adverse events. Mean exercise session adherence was 94±4% and the mean number of sessions was 39±4. Concerning the performance outcomes, we observed significant improvements in the step-test (80±22 to 93±25 steps; p<0.001) and handgrip measurement (28±7 to 30±7 kgf; p<0.001), alongside an approximate 4% increase in lean body mass (13±2 to 14±2; p<0.001) during the 6-month period. Furthermore, the patient-reported outcomes (KDQOL-SF) improved with enhancements in physical functioning (64±22 to 72±23 points; p<0.001), general health (55±23 to 61±21 points; p=0.01), social function (73±26 to 80±21 points; p=0.004), physical (43±9 to 47±8; p<0.001) and mental composite scores (46±10 to 48±9 points; p=0.04), along with a reduction in fatigue (57±17 to 60±17 points; p=0.03). The Kt/Vurea showed an improvement between the 1st and 6th months of the program (1.4±0.7 vs. 2.3±8.1; p<0.05). A similar favorable trend was observed for the URR, demonstrating improvement from program’s beginning to the end of the exercise program (68±10 vs. 71±8; p<0.05).
Our study demonstrates that the supervised exercise program for maintenance HDF patients was safe and associated with improvements in patient-reported and performance outcomes. Overall, these findings support the potential benefits of exercise as an adjunct therapy for HDF patients.