1. Investigación

Accurate evaluation of physical function in patients undergoing haemodialysis is crucial in the analysis of the impact of exercise programs in this population. The aim of this study was to evaluate the reproducibility of several physical functional tests, depending on the timing of their implementation (before the HD session vs. non-HD days). This is a prospective, non-experimental, descriptive study. Thirty patients in haemodialysis were evaluated twice, 1 week apart. The test session was performed before the haemodialysis session started and a retest was performed in non-dialysis day. The testing battery included the short physical performance battery, sit-to-stand tests, 6 min walk test, one-leg stand test, timed up and go, and handgrip strength with and without forearm support. The intrarater reproducibility was determined by the intraclass correlation coefficients and the agreement was assessed by Bland–Altman analysis. The intraclass correlation coefficients values ranged from 0.86 to 0.96, so that all tests showed good to very good relative reliability. The mean differences between trials of sit to stand 10 and 60, timed up and go and all the handgrip tests were close to zero, indicating no systematic differences between trials. Large range of values between trials was observed for the 6 min walk test, gait speed, one-leg stand test and short physical performance battery, indicating a systematic bias for these four tests. In conclusion, the sit to stand 10 and 60, timed up and go and handgrip tests had good to excellent test–retest reliability in measuring physical function in different dialysis days of patients undertaking haemodialysis. The minimal detectable change values are provided for this population. Bias were found for the 6 min walk test, gait speed, Short physical performance battery or one-leg stand test when the testing day changed.

Background: Exercise improves the physical function of people suffering from chronic kidney disease on hemodialysis (HD). Virtual reality is a new type of intradialysis exercise that has a positive impact on physical function. Intradialysis exercise is recommended during the first 2 h, but its safety in the last part of the dialysis session is unknown. Methods: This was a pilot sub-study of a clinical trial. Several hemodynamic control variables were recorded, including blood pressure, heart rate, and intradialytic hypotensive events. These variables were recorded during three different HD sessions, one HD session at rest, another HD session with exercise during the first two hours, and one HD session with exercise during the last 30 min of dialysis. The intradialysis virtual reality exercise was performed for a maximum of 30 min. Results: During exercise sessions, there was a significant increase in heart rate (6.65 (4.92, 8.39) bpm; p < 0.001) and systolic blood pressure (6.25 (0.04,12.47) mmHg; p < 0.05). There was no difference in hemodynamic control between the sessions with exercise during the first two hours and the sessions with exercise during the last 30 min. There was no association between intra-dialytic hypotensive events at rest (five events) or exercise at any point (two vs. one event(s), respectively). Conclusion: performing exercise with virtual reality at the end of a hemodialysis session is not associated with hemodynamic instability.

It has been suggested that physical exercise in chronic hemodialysis could improve dialysis dose and reduce postdialysis rebound. A randomized controlled trial was performed to compare a group of patients doing physical exercise during the first 2 h of hemodialysis sessions and another group doing physical exercise at home. The descriptive variables, dialysis doses measured by KtV, and rebounds (urea, creatinine, potassium, phosphorus), were recorded. For 69 patients: the mean KtV was 1.84; the 30-min rebound of creatinine was 32.37%, urea 24.39%, potassium 15.31%, and phosphorus 51.29%. For each patient, the basal measurement was compared with those determined when performing physical exercise; no statistically significant differences were observed between the changes determined to dose and rebound in the group with hemodialysis exercise compared to those of the home exercise group. In conclusion, performing physical exercise during the first 2 hours of hemodialysis sessions neither lowered postdialysis molecules rebound nor improved dialysis dose.

The aim of this study was to determine the extent to which poor physical functioning, low participation in physical activity and muscle atrophy observed among patients on hemodialysis are evident in the earlier stages of chronic kidney disease (CKD). We enrolled adults in three groups: no CKD, stage 3-4 CKD, and hemodialysis. Outcomes measured were physical activity, muscle size, thigh muscle strength, physical performance, and self-reported physical function. Patients with CKD had muscle area intermediate between the no CKD and hemodialysis groups, but they had low levels of physical activity that were similar to the hemodialysis group. Physical activity and muscle size were significantly associated with all outcomes. Kidney function was not significantly associated with muscle strength or physical performance after adjustment for physical activity and muscle size. In conclusion, interventions aimed to increase muscle mass and energy expenditure might have an impact on improving physical function of CKD patients.

Objective: The main objective of this investigation was to assess feasibility of conducting a future RCT with an intradialysis non-immersive virtual reality exercise intervention. The secondary aim was to explore the impact of either conventional or VR exercise on physical function. Design: Feasibility randomized trial Participants: 18 subjects who participated in a 16 weeks intradialysis combined exercise program. Interventions: The program lasted 4 additional weeks of either combined exercise or virtual reality exercise. Main outcome measures: Physical function was measured through several reliable tests (sit to stand to sit tests 10 and 60, gait speed, one-leg heel rise tests and 6-minute walk test) at baseline, after 16 weeks of intradialysis combined exercise and by the end of 4 additional weeks of exercise. Adherence to the exercise programs was registered. Results: There was a significant time effect, so that physical function improved in both groups. By the end of the 20 weeks, function improved as measured through the sit to stand to sit test 10 and 60, gait speed, one-leg heel rise left leg and the 6-minute walk test. Changes that did not occur due to error in the test were seen after 20 weeks were achieved in the sit to stand to sit test 60, gait speed, one-leg heel rise test for the left leg and 6-minute walking test. Conclusion: Virtual reality was a feasible intervention. Both interventions improved physical function. Adherence was not significantly different between groups.

Functional tests are commonly used for chronic kidney disease (CKD) patients undergoing hemodialysis (HD). However, the relative and absolute reliability of such physical performance-outcome assessments must first be determined in specific patient cohorts. The aims of this study were to assess the relative and the absolute reliability of the Short Physical Performance Battery (SPPB), One-Legged Stance Test (OLST), and Timed Up and Go (TUG) test, as well as the minimal detectable change (MDC) scores for these tests in CKD patients receiving HD. Seventy-one end-stage CKD patients receiving HD therapy, aged between 21 and 90 years, participated in the study. The patients completed two testing sessions one to two weeks apart and performed by the same examiner, comprising the following tests: the SPPB (n = 65), OLST (n = 62), and TUG test (n = 66). High intraclass correlation coefficients ( 0.90) were found for all the tests, suggesting that their relative reliability is excellent. The MDC scores for the 90% confidence intervals were as follows: 1.7 points for the SPPB, 11.3 seconds for the OLST, and 2.9 seconds for the TUG test. The reliability of the SPPB, OLST, and TUG test for this sample were all considered to be acceptable. The MDC data generated by these tests can be used to monitor meaningful changes in the functional capacity of the daily living-related activity of CKD patients on HD.