Test-Retest Reliability for Physical Function Measures in Patients with Chronic Kidney Disease.

BACKGROUND: It is important to determine relative and absolute reliability values in outcome measures that are used in clinical practice so as to discriminate between true changes following exercise interventions for patients with chronic kidney disease (CKD). OBJECTIVE: The study aimed to assess test-retest reliability of the incremental shuttle walk test (ISWT), sit-to-stand transfers in 60 seconds (STS-60), timed up and go (TUAG), Duke's activity status index (DASI) and hospital anxiety and depression scale (HAD) in patients with CKD. STUDY DESIGN: This study was a pragmatic non-randomised controlled trial. METHODS: Forty people attended two study visits within a 16-day window involving the ISWT, STS-60, TUAG, DASI and HAD tests. Relative reliability was assessed using intraclass correlation coefficient (ICC) and absolute reliability using the standard error of measurement (SEM) and minimal detectable change (MDC). RESULTS: Good test-retest reliability was found for the entire sample size across all outcome measures, with TUAG having the highest (ICC = 0.96) and HAD the lowest (ICC = 0.71). The MDC scores at 90% confidence interval (CI) were: 79.6 m for the ISWT, 2.9 seconds for the TUAG, 7.0 repetitions for the STS-60, 8.4 for the DASI, 3.8 for the anxiety HAD subscale and 4.4 for the depression HAD subscale. CONCLUSIONS: This study demonstrated good test-retest reliability for all outcome measures across the CKD trajectory but caution needs to be taken when interpreting the findings for each CKD sub-group separately. The MDC scores at 90% CI can support therapists in determining a true improvement in CKD patients' physical or mental performance.

Mortality and morbidity following exercise-based renal rehabilitation in patients with chronic kidney disease: the effect of programme completion and change in exercise capacity.

BACKGROUND: Twelve weeks of renal rehabilitation (RR) have been shown to improve exercise capacity in patients with chronic kidney disease (CKD); however, survival following RR has not been examined. METHODS: This study included a retrospective longitudinal analysis of clinical service outcomes. Programme completion and improvement in exercise capacity, characterised as change in incremental shuttle walk test (ISWT), were analysed with Kaplan-Meier survival analyses to predict risk of a combined event including death, cerebrovascular accident, myocardial infarction and hospitalisation for heart failure in a cohort of patients with CKD. Time to combined event was examined with Kaplan-Meier plots and log rank test between 'completers' (attended >50% planned sessions) and 'non-completers'. In completers, time to combined event was examined between 'improvers' (≥50 m increase ISWT) and 'non-improvers' (<50 m increase). Differences in time to combined event were investigated with Cox proportional hazards models (adjusted for baseline kidney function, body mass index, diabetes, age, gender, ethnicity, baseline ISWT and smoking status). RESULTS: In all, 757 patients (male 54%) (242 haemodialysis patients, 221 kidney transplant recipients, 43 peritoneal dialysis patients, 251 non-dialysis CKD patients) were referred for RR between 2005 and 2017. There were 193 events (136 deaths) during the follow-up period (median 34 months). A total of 43% of referrals were classified as 'completers', and time to event was significantly greater when compared with 'non-completers' (P = 0.009). Responding to RR was associated with improved event-free survival time (P = 0.02) with Kaplan-Meier analyses and log rank test. On multivariate analysis, completing RR contributed significantly to the minimal explanatory model relating clinical variables to the combined event (overall χ2 = 38.0, P < 0.001). 'Non-completers' of RR had a 1.6-fold [hazard ratio = 1.6; 95% confidence interval (CI) 1.00-2.58] greater risk of a combined event (P = 0.048). Change in ISWT of >50 m contributed significantly to the minimal explanatory model relating clinical variables to mortality and morbidity (overall χ2 = 54.0, P < 0.001). 'Improvers' had a 40% (hazard ratio = 0.6; 95% CI 0.36-0.98) independent lower risk of a combined event (P = 0.041). CONCLUSIONS: There is an association between completion of an RR programme, and also RR success, and a lower risk of a combined event in this observational study. RR interventions to improve exercise capacity in patients with CKD may reduce risk of morbidity and mortality, and a pragmatic randomised controlled intervention trial is warranted.

Long-term pulse wave velocity outcomes with aerobic and resistance training in kidney transplant recipients - A pilot randomised controlled trial.

BACKGROUND: This pilot study examined long-term pulse wave velocity (PWV) and peak oxygen uptake (VO2peak) outcomes following a 12-week moderate-intensity aerobic or resistance training programme in kidney transplant recipients. METHOD: Single-blind, bi-centre randomised controlled parallel trial. 42 out of 60 participants completed a 9-month follow-up assessment (Aerobic training = 12, Resistance training = 10 and usual care = 20). Participants completed 12 weeks of twice-weekly supervised aerobic or resistance training. Following the 12-week exercise intervention, participants were transitioned to self-managed community exercise activity using motivational interviewing techniques. Usual care participants received usual encouragement for physical activity during routine clinical appointments in the transplant clinic. PWV, VO2peak, blood pressure and body weight were assessed at 12 weeks and 12 months, and compared to baseline. RESULTS: ANCOVA analysis, covarying for baseline values, age, and length of time on dialysis pre-transplantation, revealed a significant mean between-group difference in PWV of -1.30 m/sec (95%CI -2.44 to -0.17, p = 0.03) between resistance training and usual care groups. When comparing the aerobic training and usual care groups at 9-month follow-up, there was a mean difference of -1.05 m/sec (95%CI -2.11 to 0.017, p = 0.05). A significant mean between-group difference in relative VO2peak values of 2.2 ml/kg/min (95% CI 0.37 to 4.03, p = 0.02) when comparing aerobic training with usual care was revealed. There was no significant between group differences in body weight or blood pressure. There were no significant adverse effects associated with the interventions. CONCLUSIONS: Significant between-group differences in 9-month follow-up PWV existed when comparing resistance exercise intervention with usual care. A long-term between-group difference in VO2peak was only evident when comparing aerobic intervention with usual care. This pilot study, with a small sample size, did not aim to elucidate mechanistic mediators related to the exercise interventions. It is however suggested that a motivational interviewing approach, combined with appropriate transition to community training programmes, could maintain the improvements gained from the 12-week exercise interventions and further research in this area is therefore warranted. TRIAL REGISTRATION: study number: ISRCTN43892586.

Aerobic or Resistance Training and Pulse Wave Velocity in Kidney Transplant Recipients: A 12-Week Pilot Randomized Controlled Trial (the Exercise in Renal Transplant [ExeRT] Trial).

BACKGROUND: Cardiovascular disease remains the leading cause of death in kidney transplant recipients. This pilot study examined the potential effect of aerobic training or resistance training on vascular health and indexes of cardiovascular risk in kidney transplant recipients. STUDY DESIGN: Single-blind, randomized, controlled, parallel trial. SETTING & PARTICIPANTS: 60 participants (mean age, 54 years; 34 men) were randomly assigned to aerobic training (n=20), resistance training (n=20), or usual care (n=20). Participants were included if they had a kidney transplant within 12 months prior to baseline assessment. Patients were excluded if they had unstable medical conditions or had recently started regular exercise. INTERVENTION: Aerobic training and resistance training were delivered 3 days per week for a 12-week period. The usual-care group received standard care. OUTCOMES & MEASUREMENTS: Pulse wave velocity, peak oxygen uptake (Vo2peak), sit-to-stand 60, isometric quadriceps force, and inflammatory biomarkers were assessed at 0 and 12 weeks. RESULTS: The anticipated 60 participants were recruited within 12 months. 46 participants completed the study (aerobic training, n=13; resistance training, n=13; and usual care, n=20), resulting in a 23% attrition rate. Analyses of covariance, adjusted for baseline values, age, and dialysis vintage pretransplantation, revealed significant mean differences between aerobic training and usual care in pulse wave velocity of -2.2±0.4 (95% CI, -3.1 to -1.3) m/s (P<0.001) and between resistance training and usual care of -2.6±0.4 (95% CI, -3.4 to -1.7) m/s (P<0.001) at 12 weeks. Secondary analyses indicated significant improvements in Vo2peak in the aerobic training group and in Vo2peak, sit-to-stand 60, and isometric muscle force in the resistance training group compared with usual care at 12 weeks. There were no reported adverse events, cardiovascular events, or hospitalizations as a result of the intervention. LIMITATIONS: Pilot study, small sample size, no measure of endothelial function. CONCLUSIONS: Both aerobic training and resistance training interventions appear to be feasible and clinically beneficial in this patient population.

Effect of exercise training on estimated GFR, vascular health, and cardiorespiratory fitness in patients with CKD: a pilot randomized controlled trial.

BACKGROUND: Exercise capacity, which is predictive of all-cause mortality and cardiovascular disease risk, is reduced significantly in patients with non-dialysis-dependent chronic kidney disease. This pilot study examined the effect of moderate-intensity exercise training on kidney function and indexes of cardiovascular risk in patients with progressive chronic kidney disease stages 3 to 4. STUDY DESIGN: Single-blind, randomized, controlled, parallel trial. SETTING & PARTICIPANTS: 20 patients (aged 18-80 years; 17 men) randomly assigned to rehabilitation (n=10) or usual care (n=10). Participants were included if they were 18 years or older and had evidence of rate of decline in creatinine-based estimated glomerular filtration rate (eGFRcr)≥2.9mL/min/1.73m(2) per year for 12 months preintervention. Patients were excluded if they had unstable medical conditions or had recently started regular exercise. INTERVENTION: The rehabilitation group received resistance and aerobic training (3 days per week) for a 12-month period. The usual care group received standard care. OUTCOMES: Kidney function assessed by comparing mean rate of change in eGFRcr (mL/min/1.73m(2) per year) from a 12-month preintervention period against the 12-month intervention period. Pulse wave velocity (PWV), peak oxygen uptake (Vo2peak), and waist circumference assessed at 0, 6, and 12 months. MEASUREMENTS: eGFR assessed using creatinine, cystatin C (eGFRcys), and a combination of both values (eGFRcr-cys). RESULTS: 18 participants (rehabilitation, 8; usual care, 10) completed the study. A significant mean difference in rate of change in eGFRcr (+7.8±3.0 [95% CI, 1.1-13.5] mL/min/1.73m(2) per year; P=0.02) was observed between the rehabilitation and usual care groups, with the rehabilitation group demonstrating a slower decline. No significant between-group mean differences existed in absolute eGFRcr, eGFRcr-cys, or eGFRcys at 12 months of study intervention. Significant between-group mean differences existed in PWV (-2.30 [95% CI, -3.02 to -1.59] m/s), waist circumference (-7.1±12.8 [95% CI, -12.4 to -3.2] cm), and Vo2peak (5.7 [95% CI, 1.34-10.10] mL/kg/min). Change in eGFRcr was correlated inversely with PWV (r=-0.5; P=0.04) at 12 months. LIMITATIONS: Small sample size, inconsistency between primary and secondary measures of kidney function. CONCLUSIONS: The effect of a 1-year exercise intervention on progression of kidney disease is inconclusive. A larger study with longer follow-up may be necessary.

Evaluation of a pragmatic exercise rehabilitation programme in chronic kidney disease.

BACKGROUND: Physical activity has the potential to positively impact upon aerobic and functional ability, and the quality of life of all chronic kidney disease (CKD) patients independent of the stage of the disease process. Physical activity is recommended in a number of national CKD guidelines, but its incorporation into routine care has been slow. The translation of research-led physical activity programmes into an established procedure appears to be a particular obstacle. This study included 263 patients, consecutively referred over a 4-year period, to a pragmatic 12-week renal rehabilitation (RR) programme delivered within a National Health Service (NHS). METHODS: One hundred and thirty-one patients were assessed and started the RR programme. Anxiety and depression were measured using the hospital anxiety and depression (HAD) scale. The self-reported level of fitness was measured with the Duke's activity status index (DASI), and exercise capacity was assessed with the incremental shuttle walk test (ISWT), sit-to-stand transfers in 60 s (STS60), timed up and go (TUAG) and stair-climb descent (SCD) tests. All measures were assessed at baseline and at 12 weeks. Attendance and completion of the RR programme were recorded for all patients. RESULTS: There were significant improvements in exercise capacity and functional ability ranging from 21 to 44%, and significant improvements in anxiety (15%) and depression (29%) in the 77 patients who completed the RR programme. The self-reported level of fitness was found to be significantly associated with completion (P = 0.01), with older participants showing a trend towards being more likely to complete (P= 0.07). Fifty-four patients, out of the 131 patients who commenced the RR programme, failed to complete 12 or more of the 24 scheduled sessions. Patients requiring haemodialysis (HD) treatment constituted the largest number of dropouts/non-completers (49%) in the study. CONCLUSIONS: This study demonstrates that a pragmatically constructed, NHS-delivered exercise-based RR can substantially improve both physical function and mental well-being for the wide range of CKD patients who regularly participated (55%). Compliance/adherence data indicate that this type of rehabilitation programme is particularly well received by pre-dialysis (PD) CKD and post-transplantation patients.