Clinical and demographic predictors of exercise capacity in end-stage renal disease

Real-world evidence on the dosing and safety of C.E.R.A. in pediatric dialysis patients: findings from the International Pediatric Dialysis Network registries

BACKGROUND

This retrospective real-world study used data from two registries, International Pediatric Peritoneal Dialysis Network (IPPN) and International Pediatric Hemodialysis Network (IPHN), to characterize the efficacy and safety of continuous erythropoietin receptor activator (C.E.R.A.) in pediatric patients with chronic kidney disease (CKD) on peritoneal dialysis (PD) or hemodialysis (HD).

METHODS

IPPN and IPHN collect prospective data (baseline and every 6 months) from pediatric PD and HD centers worldwide. Demographics, clinical characteristics, dialysis information, treatment, laboratory parameters, number and causes of hospitalization events, and deaths were extracted for patients on C.E.R.A. treatment (IPPN: 2007-2021; IPHN: 2013-2021).

RESULTS

We analyzed 177 patients on PD (median age 10.6 years) and 52 patients on HD (median age 14.1 years) who had ≥ 1 observation while being treated with C.E.R.A. The median (interquartile range [IQR]) observation time under C.E.R.A. exposure was 6 (0-12.5) and 12 (0-18) months, respectively. Hemoglobin concentrations were stable over time; respective means (standard deviation) at last observation were 10.9 (1.7) g/dL and 10.4 (1.7) g/dL. Respective median (IQR) monthly C.E.R.A. doses at last observation were 3.5 (2.3-5.1) µg/kg, or 95 (62-145) µg/m2 and 2.1 (1.2-3.4) µg/kg, or 63 (40-98) µg/m2. Non-elective hospitalizations occurred in 102 (58%) PD and 32 (62%) HD patients. Seven deaths occurred (19.8 deaths per 1000 observation years).

CONCLUSIONS

C.E.R.A. was associated with efficient maintenance of hemoglobin concentrations in pediatric patients with CKD on dialysis, and appeared to have a favorable safety profile. The current analysis revealed no safety signals.

Home-based exercise in dialysis patients with end-stage renal disease: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Lack of exercise may reduce the quality of life, physical capability, and functional capability of dialysis patients. Home-based exercise seems to be a desirable form of low-cost intervention. But the effectiveness of this intervention in the dialysis population is still unclear. The purpose of this meta-analysis is to provide effective evidence to determine the impact of home-based exercise on functional capacity, physical capacity, muscular strength, biochemical parameters, and health-related quality of life among dialysis patients with end-stage renal disease (ESRD).

METHODS

PubMed, Embase, Cochrane Library, and Web of Science were searched from inception to May 2023, to identify potential randomized controlled trials (RCTs) assessing the effectiveness of home-based exercise in dialysis patients with ESRD. Two independent reviewers selected studies, extracted data, and assessed the risk of bias using the Cochrane tool. Evidence summary using fixed or random effects for meta-analysis.

RESULTS

Twelve RCTs including 1008 dialysis patients met the inclusion criteria. The meta-analysis showed significant effects of home-based exercise on physical capacity. Seven studies reported the results of the 6-min walking test, compared with short-term (0-3 months) home-based exercise (P = 0.76), long-term (3-6 months) interventions (P < 0.001) can significantly improve the results of the 6-min walking test. The results showed that home-based exercise did significantly improve patients' VO2 peak (P = 0.007). Compared with center-based exercise or usual care, home exercise did not significantly improve handgrip strength, quality of life or CRP and other biochemical parameters (P > 0.05).

CONCLUSION

The results showed that long-term home-based exercise can improve walking ability. In addition, home-based exercise had the benefit on the VO2 peak of ESRD patients receiving dialysis patients. However, there was no statistically significant difference in handgrip strength, health-related quality of life, CRP, and other biochemical parameters.

Relationships between frailty and exercise capacity in patients undergoing hemodialysis: A cross-sectional study

AIM

Hemodialysis (HD) patients have a high prevalence of frailty. The association between frailty and exercise capacity in HD patients has not been established. This study aimed to clarify the relationships between frailty and exercise capacity in HD patients.

METHODS

This two-center cross-sectional study included HD patients who performed cardiopulmonary exercise testing. Participants were divided by frailty phenotype into robust, pre-frail, and frail using the revised Japanese version of the Cardiovascular Health Study criteria. Peak oxygen uptake (peakVO2 ) measured by cardiopulmonary exercise testing was compared with each frailty phenotype. The association between peakVO2 and frailty phenotype was analyzed using multivariate linear regression analysis adjusted for age, sex, body mass index diabetes mellitus, cardiovascular disease, cancer, history of fracture, hemoglobin, left ventricle ejection fraction, and percentage of heart rate reserve.

RESULTS

The study included 136 patients (median age, 71.0 years; female, 23.5%), with 15.4%, 44.9%, and 39.7% with frailty phenotypes robust, pre-frail, and frail, respectively. PeakVO2 decreased with deterioration of the frailty phenotype (robust, median 15.1 [13.7-18.3] mL/min/kg; pre-frail, median 12.2 [10.5-14.4] mL/min/kg; frail, median 10.6 [9.2-12.5] mL/min/kg, P < 0.05). PeakVO2 decline was significantly associated with frail (B = -2.19, P = 0.004). Modeling individual frailty components showed a significant association between peakVO2 , usual gait speed (B = 2.38, P = 0.04), and low physical activity (B = -1.44, P = 0.004).

CONCLUSION

Frailty in HD patients was associated with a decline in exercise capacity. HD patients with frailty need to improve exercise capacity, gait speed, and physical activity. Geriatr Gerontol Int 2023; 23: 795-802.

Correlation between acylcarnitine/free carnitine ratio and cardiopulmonary exercise test parameters in patients with incident dialysis

Objective: Diminished physical capacity is common and progressive in patients undergoing dialysis, who are also prone to deficiency in carnitine, which plays a pivotal role in maintaining skeletal muscle and cardiac function. The present study aimed to evaluate the association of carnitine profile with exercise parameters in patients with incident dialysis. Design and Methods: This was a single-center cross-sectional study including 87 consecutive patients aged 20-90 years who were initiated on dialysis in Keio University Hospital between December 2019 and December 2022 and fulfilled the eligibility criteria. Exercise parameters were evaluated via cardiopulmonary testing (CPX) using the electronically braked STRENGTH ERGO 8 ergometer, whereas the carnitine profile was assessed by determining serum free carnitine (FC), acylcarnitine (AC) levels and AC/FC ratio. Results: The mean cohort age was 62.1 ± 15.2 years, with male and hemodialysis predominance (70% and 73%, respectively). AC/FC was 0.46 ± 0.15, and CPX revealed peak oxygen consumption (VO₂) of 13.9 ± 3.7 (mL/kg/min) with percent-predicted peak VO₂ of 53.6% ± 14.7% and minute ventilation (VE)/carbon dioxide output (VCO₂) slope of 35.1 ± 8.0. Fully-adjusted multivariate linear regression analysis showed that AC/FC was significantly associated with decreased peak VO₂ (β, -5.43 [95% confidence interval (CI), -10.15 to -0.70]) and percent-predicted peak VO₂ (β, -19.98 [95% CI, -38.43 to -1.52]) and with increased VE/VCO₂ slope (β, 13.76 [95% CI, 3.78-23.75]); FC and AC did not exhibit similar associations with these parameters. Moreover, only AC/FC was associated with a decreased peak work rate (WR), percent-predicted WR, anaerobic threshold, delta VO₂/delta WR, and chronotropic index. Conclusion: In patients on incident dialysis, exercise parameters, including those related to both skeletal muscle and cardiac function, were strongly associated with AC/FC, a marker of carnitine deficiency indicating altered fatty acid metabolism. Further studies are warranted to determine whether carnitine supplementation can improve exercise capacity in patients on incident dialysis.

REHABILITATION OUTCOMES IN PATIENTS WITH LOWER LIMB AMPUTATION RECEIVING HAEMODIALYSIS: A RETROSPECTIVE COHORT STUDY

OBJECTIVE

To compare the functional outcomes of patients with lower limb amputations receiving haemodialysis and those not receiving haemodialysis.

DESIGN

A retrospective cohort study.

PATIENTS

Patients with lower limb amputation who were admitted to a convalescent rehabilitation ward between January 2018 and December 2021.

METHODS

The primary outcome was the effectiveness of the Functional Independence Measure (FIM) during hospitalisation in the ward. Secondary outcomes included the total and subtotal (motor/cognitive) FIM scores at discharge, gain in the total and subtotal (motor/cognitive) FIM scores, K-level at discharge, length of hospital stay in the ward, rehabilitation time, and discharge destination. Outcomes were compared between the non-haemodialysis and haemodialysis groups.

RESULTS

A total of 28 patients (mean [standard deviation] age, 67.0 [11.9] years; men, 20) were enrolled in this study. Among them, 11 patients underwent haemodialysis. The FIM effectiveness was significantly higher in the non-haemodialysis group than in the haemodialysis group (median [interquartile range], 0.78 [0.72 - 0.81] vs 0.65 [0.28 - 0.75], p = 0.038). The amount of rehabilitation and all secondary outcomes were not significantly different between the groups (p > 0.05).

CONCLUSION

Patients with lower limb amputation who were receiving haemodialysis had poorer FIM effectiveness than those not receiving haemodialysis.

Cardiopulmonary exercise testing in patients with end-stage kidney disease: principles, methodology and clinical applications of the optimal tool for exercise tolerance evaluation

Chronic kidney disease (CKD), especially end-stage kidney disease (ESKD), is associated with an increased risk for cardiovascular events and all-cause mortality. Exercise intolerance as well as reduced cardiovascular reserve is extremely common in patients with CKD. Cardiopulmonary exercise testing (CPET) is a non-invasive, dynamic technique that provides an integrative evaluation of cardiovascular, pulmonary, neuropsychological and metabolic function during maximal or submaximal exercise, allowing the evaluation of functional reserves of these systems. This assessment is based on the principle that system failure typically occurs when the system is under stress and thus CPET is currently considered to be the gold standard for identifying exercise limitation and differentiating its causes. It has been widely used in several medical fields for risk stratification, clinical evaluation and other applications, but its use in everyday practice for CKD patients is scarce. This article describes the basic principles and methodology of CPET and provides an overview of important studies that utilized CPET in patients with ESKD, in an effort to increase awareness of CPET capabilities among practicing nephrologists.

Cardiopulmonary exercise testing to observe subclinical abnormalities in cardiopulmonary function in patients undergoing peritoneal dialysis

BACKGROUND

Decreased cardiorespiratory fitness (CRF) related to cardiopulmonary function increases the risk of cardiovascular disease in patients with end-stage kidney disease. Thus, early detection of the cause of impaired cardiopulmonary function in patients undergoing peritoneal dialysis (PD) is of important clinical significance.

METHODS

In this cross-sectional study, Symptom-restricted cardiopulmonary exercise testing (CPET) was performed in 30 patients undergoing PD and in 23 age- and sex-matched healthy control subjects.A fixed workload was added every minute until fatigue, and breath-by-breath respiratory gas was analyzed with an automated gas analyzer at 10-second intervals.

RESULTS

The peak oxygen uptake ( 16.39±0.83 vs 25.77±1.33 ml/kg/min p<0.001) and the oxygen uptake at the anerobic threshold of patients undergoing PD (9.61±0.34 vs 14.55± 0.64 ml/kg/min; p<0.001) were lower than in healthy control subjects, and both of these parameters correlated with body mass index and left atrial dimension. A steeper minute ventilation / carbon dioxide production slope (27.20±0.68 vs 24.29±0.69；p<0.01) and a lower end-tidal carbon dioxide partial pressure (37.93±0.54 vs 41.27±0.83mmHg；p<0.05) were observed in patients undergoing PD. The oxygen pulse and oxygen uptake efficiency slope was smaller in patients undergoing PD. The Maximum heart rate (126.07±4.01 vs 149.96±5.29 bpm；p<0.01) and 1-minute heart rate recovery (13.93±1.52 vs 24.39±1.61bpm；p<0.01) were also lower in patients undergoing PD.

CONCLUSION

Subclinical cardiopulmonary dysfunction may exist in patients with PD, and a reduction in CRF in patients undergoing PD is affected by both central and peripheral functions. CPET has potential value in revealing the mechanism of impaired CRF and in discovering subclinical abnormalities in cardiopulmonary function. This article is protected by copyright. All rights reserved.

Correlation between functional capacity and oxidative stress and inflammation in hemodialysis patients

INTRODUCTION

Patients with chronic kidney disease (CKD) may present impaired functional capacity due to peripheral muscle involvement. Oxidative stress and inflammation are probably involved in this pathophysiology. This study aimed to evaluate the association between functional capacity and biomarkers of oxidative stress as well as biomarkers of inflammation in patients under chronic hemodialysis therapy.

METHOD

Cross-sectional study including 41 patients from a single hemodialysis center. Functional capacity was assessed through the 6-min walk test (6MWT). The assessed blood biomarkers were: malondialdehyde (MDA) (oxidative stress, TBARS method) and angiopoietin-2 (Ang-2) (inflammation, ELISA). The influence of gender on impairment of functional capacity was further explored.

RESULTS

There was an inversely proportional correlation between the 6MWD and MDA (r = -,322 and p = 0.040) and Ang-2 (r = -, 376 and p = 0.016) values. 6MWD was 370.9 ± 101.2 m and 391.4 ± 108.2 m in women and men, respectively (p < 0.001), which means 29.3% and 34.3% reduction of the expected values for healthy individuals from the same age range.

CONCLUSION

Patients with CKD under hemodialysis, regardless of gender, presented impaired performance in 6MWT and this impairment was associated with oxidative stress and inflammation.

Efficacy of Exercise Therapy Initiated in the Early Phase After Kidney Transplantation: A Pilot Study

OBJECTIVE

In patients with kidney transplant (KT), frailty is a predictor of adverse outcomes. Outcomes of exercise therapy in patients with KT, particularly the efficacy of early exercise after KT, have not been evaluated. We investigated the effect of exercise intervention beginning early after KT on physical performance, physical activity, quality of life, and kidney function in patients with KT.

METHODS

KT recipients who underwent surgery with usual care plus exercise training from a prospective cohort (exercise group; n = 10) and those with usual care alone from a historical cohort (control group; n = 14) were included in this study. Early exercise comprised supervised aerobic training and physical activity instruction from day 6 to 2 months after KT. The following outcomes were measured: 6-minute walking distance, isometric knee extensor strength, gait speed, physical activity, quality of life, and estimated glomerular filtration rate.

RESULTS

Analyses of covariance, adjusted for baseline values, revealed significant mean differences between exercise and control groups at 2 months after KT in 6-minute walking distance (+44.4 m, P = .03) and isometric knee extensor strength (+8.1%body weight, P = .03). No significant between-group differences were found in gait speed, physical activity, and quality of life. The analysis of variance for comparison of the area under the recovery curves of estimated glomerular filtration rate after KT revealed no significant difference between groups.

CONCLUSION

Supervised aerobic training and physical activity instruction initiated in the early phase after KT can improve physical performance without adversely affecting kidney function.

Reduction of functional cardiovascular reserve in the stages of chronic kidney disease

SUMMARY OBJECTIVE Patients with chronic kidney disease (CKD) present reduced oxygen consumption at peak exercise (VO2 peak). No studies have evaluated objective measures of the cardiovascular reserve, besides VO2 peak and VO2 at the anaerobic threshold (VO2 AT), and compared these measures among ckd patients at different stages of the disease. METHODS Fifty-eight patients [pre-dialysis group (PD)=26, hemodialysis group (HD)=20, and post-kidney transplant group (KT)=12] were included. The following measures of cardiovascular reserve were obtained: 1) peak heart rate (HR); 2) peak systolic blood pressure (SBP); 3) VO2 peak and % predicted; 4) VO2 AT and % of predicted VO2; 5) peak circulatory power; 6) ventilatory efficiency for the production of carbon dioxide (VE/VCO2 slope); 7) oxygen uptake efficiency slope (OUES); and 8) recovery of gas exchange. RESULTS The VO2 peak and VO2 AT in the PD, HD, and KT groups were reduced to 86% and 69%, 70% and 57%, and 79% and 64% of the predicted value, respectively. Patients in the HD group had lower VO2 peak (17.5±5.9 vs. 23.2±8.2 [p-value=0.036]) and VO2 AT (14.0±5.2 vs. 18.3±4.7 [p-value=0.039]) compared to patients in the KT group. OUES was significantly lower in the HD group compared to the KT group (p-value=0.034). Age in the PD, HD, and KT groups and sedentary lifestyle in the KT group were predictors of VO2 peak. CONCLUSIONS CKD patients presented a reduction in cardiovascular reserve regardless of the stage of the disease. However, hemodialysis patients presented a greater reduction of cardiovascular reserve when compared to post-kidney transplant patients.

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.

Exercise Capacity and Association with Quality of Life in Peritoneal Dialysis Patients

BACKGROUND

Muscle wasting, common and progressive in uremic patients, is associated with a high probability for morbidity, lower health-related quality of life (HRQOL), and mortality. However, exercise tolerance in peritoneal dialysis (PD) patients has not been fully elucidated. The aim of this study was to evaluate exercise capacity, its determinants, and its association with HRQOL in PD patients.

METHODS

Outpatients treated with PD at Keio University Hospital from December 2016 to March 2018 were included in this single-center cross-sectional observational study. Exercise capacity was assessed by incremental shuttle walking test (ISWT) and handgrip and quadriceps strength. In addition to evaluation of PD-related parameters, HRQOL was assessed by the Kidney Disease Quality of Life-Short Form questionnaire.

RESULTS

Among the 50 recruited PD outpatients, age and PD vintage were 63.8 ± 9.6 and 3.8 ± 2.8 years, respectively. Physical examination revealed ISWT of 312.0 ± 138.2 m, handgrip strength of 27.5 ± 6.9 kg, and quadriceps strength of 23.3 ± 10.0 kg. Multivariate analysis showed that younger age and male sex were significantly associated with higher ISWT and handgrip and quadriceps strength. Skeletal mass index (SMI) remained a significant predictor of handgrip and quadriceps strength. Moreover, only ISWT was strongly correlated with higher HRQOL scores, including physical, mental, and kidney-specific domains, even after adjustment for age and sex.

CONCLUSIONS

Exercise tolerance in PD patients was partially determined by age, sex, and SMI. Moreover, this is the first study to demonstrate the strong relationship between aerobic capacity and HRQOL in PD patients.

Home-based versus center-based aerobic exercise on cardiopulmonary performance, physical function, quality of life and quality of sleep of overweight patients with chronic kidney disease

BACKGROUND

The association between chronic kidney disease (CKD) and obesity can decrease the patients' cardiopulmonary capacity, physical functioning and quality of life. The search for effective and practical alternative methods of exercise to engage patients in training programs is of great importance. Therefore, we aimed to compare the effects of home-based versus center-based aerobic exercise on the cardiopulmonary and functional capacities, quality of life and quality of sleep of overweight non-dialysis-dependent patients with CKD (NDD-CKD).

METHODS

Forty sedentary overweight patients CKD stages 3 and 4 were randomly assigned to an exercise group [home-based group (n = 12) or center-based exercise group (n = 13)] or to a control group (n = 15) that did not perform any exercise. Cardiopulmonary exercise test, functional capacity tests, quality of life, quality of sleep and clinical parameters were assessed at baseline, 12 and 24 weeks.

RESULTS

The VO_2peak and all cardiopulmonary parameters evaluated were similarly improved (p < 0.05) after 12 and 24 weeks in both exercise groups. The functional capacity tests improved during the follow-up in the home-based group (p < 0.05) and reached values similar to those obtained in the center-based group. The benefits achieved in both exercise groups were also reflected in improvement of quality of life and sleep (p < 0.05). No differences were observed between the exercise groups, and no changes in any of the parameters investigated were found in the control group.

CONCLUSION

Home-based aerobic training was as effective as center-based training in improving the physical and functional capabilities, quality of life and sleep in overweight NDD-CKD patients.

Six-minute walk test predicts all-cause mortality and technique failure in ambulatory peritoneal dialysis patients

AIM

This study investigated the associated factors of 6-min walk test (6MWT) and its predictive value of outcome in patients undergoing peritoneal dialysis (PD).

METHODS

This is a single centre prospective observational cohort study. Stable ambulatory PD patients in our centre between 1 May 2010 and 30 April 2011 were enrolled in this study. All included subjects performed 6MWT, and 6-min walk distances (6MWDs) were recorded. Patients were divided into two groups according to 6MWD and prospectively followed up until death, cessation of PD or to the end of the study (30 September 2012).

RESULTS

A total of 145 patients were enrolled, including 63 (43%) males. Multiple stepwise regression showed that age (β = -0.295, P = 0.001), diastolic blood pressure (DBP) (β = 0.292, P = 0.001), left ventricular ejection fraction (LVEF) (β = 0.198, P = 0.019) were independently associated with lower 6MWD. By the end of the study, six (8%) patients died in long 6MWD group while 15 (20%) died in the short 6MWD group, a significantly lower patient survival was observed in short 6MWD group (Log-rank = 4.983, P = 0.026). Patients with short 6MWD also showed inferior technique survival (Log-rank = 4.838, P = 0.028). There was no significant difference in peritonitis-free survival between the two groups (Log-rank = 0.801, P = 0.371). However, more patients in short 6MWD group had been transferred to hemodialysis due to peritonitis (25% vs 4.2%, P = 0.013).

CONCLUSION

Age, diastolic blood pressure, LVEF are independent associated factors of 6MWD in patients undergoing PD. Having the advantages of easy applicability and safety, 6MWT may be proposed as an important predictor of outcome in ambulatory PD patients.

Endothelial dysfunction correlates with exaggerated exercise pressor response during whole body maximal exercise in chronic kidney disease

Chronic kidney disease (CKD) patients have exercise intolerance associated with increased cardiovascular mortality. Previous studies demonstrate that blood pressure (BP) and sympathetic nerve responses to handgrip exercise are exaggerated in CKD. These patients also have decreased nitric oxide (NO) bioavailability and endothelial dysfunction, which could potentially lead to an impaired ability to vasodilate during exercise. We hypothesized that CKD patients have exaggerated BP responses during maximal whole body exercise and that endothelial dysfunction correlates with greater exercise pressor responses in these patients. Brachial artery flow-mediated dilation (FMD) was assessed before maximal treadmill exercise in 56 participants: 38 CKD (56.7 ± 1.2 yr old, 38 men) and 21 controls (52.8 ± 1.8 yr old, 20 men). During maximal treadmill exercise, the slope-of-rise in systolic BP (+10.32 vs. +7.75 mmHg/stage, P < 0.001), mean arterial pressure (+3.50 vs. +2.63 mmHg/stage, P = 0.004), and heart rate (+11.87 vs. +10.69 beats·min^-1·stage^-1, P = 0.031) was significantly greater in CKD compared with controls. Baseline FMD was significantly lower in CKD (2.76 ± 0.42% vs. 5.84 ± 0.97%, P = 0.008). Lower FMD values were significantly associated with a higher slope-of-rise in systolic BP (+11.05 vs. 8.71 mmHg/stage, P = 0.003) during exercise in CKD, as well as poorer exercise capacity measured as peak oxygen uptake (V̇o_2peak; 19.47 ± 1.47 vs. 24.57 ± 1.51 ml·min^-1·kg^-1, P < 0.001). These findings demonstrate that low FMD in CKD correlates with augmented BP responses during exercise and lower V̇o_2peak, suggesting that endothelial dysfunction may contribute to exaggerated exercise pressor responses and poor exercise capacity in CKD patients.

Effect of Chronic Kidney Disease and Supplemental Polyunsaturated Fatty Acid Use on Exercise Levels During Cardiac Rehabilitation in Patients With Coronary Artery Disease

PURPOSE

The correlation between chronic kidney disease (CKD) and increased cardiovascular disease-related mortality is well established. Cardiac rehabilitation (CR) improves exercise capacity, quality of life, and risk factors in patients with coronary artery disease (CAD). Data on the benefits of CR in patients with CKD are sparse. The purpose of this study was to compare outcomes after CR in patients with CAD but normal renal function, versus those with CAD and CKD.

METHODS

We studied 804 patients with CAD entering an exercise-based CR program. Demographics, risk factors, exercise capacity in metabolic equivalent levels (METs), and estimated glomerular filtration rate (GFR) were recorded before and after the 3-month CR program. Use of polyunsaturated fatty acid (PUFA) was determined by medical records review. Stage III-V CKD (GFR <60 mL/min/1.73 m) was present in 170 patients at baseline.

RESULTS

After CR, METs improved in all patients, although increases in patients with a GFR 30 to 59 mL/min/1.73 m (Δ1.6) and a GFR <30 (Δ1.2) were smaller than those in patients with a GFR ≥60 (Δ2.6, P < .05 vs GFR 30-59 and GFR <30). In patients with a GFR ≥60 mL/min/1.73 m, PUFA use was associated with a 20% greater increase in MET levels compared with nonusers (Δ3.0 vs Δ2.5, P = .02); and in patients with a GFR 30 to 59, PUFA use was associated with 30% increase in MET level compared with nonusers (Δ2.0 vs Δ1.4, P = .03). These observations persisted after multivariable adjustment for baseline MET level, demographics, and risk factors.

CONCLUSIONS

Potential mitigation by PUFA of the smaller improvement in exercise capacity with decreasing GFR requires confirmation in prospective randomized trials.

Tetrahydrobiopterin ameliorates the exaggerated exercise pressor response in patients with chronic kidney disease: a randomized controlled trial

Chronic kidney disease (CKD) patients have an exaggerated increase in blood pressure (BP) during rhythmic handgrip exercise (RHG 20%) and static handgrip exercise (SHG 30%). Nitric oxide levels increase during exercise and help prevent excessive hypertension by both increasing vasodilation and reducing sympathetic nerve activity (SNA). Therefore, we hypothesized that tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide synthase, would ameliorate the exaggerated exercise pressor response in CKD patients. In a randomized, double-blinded, placebo-controlled trial, we tested the effects of 12 wk of sapropterin dihydrochloride (6R-BH4; n = 18) versus placebo (n = 14) treatement on BP and muscle SNA (MSNA) responses during RHG 20% and SHG 30% in CKD patients. The 6R-BH4-treated group had a significantly lower systolic BP (+6 ± 1 vs. +13 ± 2 mmHg, P = 0.002) and mean arterial pressure response (+5 ± 1 vs. +10 ± 2 mmHg, P = 0.020) during RHG 20% and a significantly lower systolic BP response (+19 ± 3 vs. +28 ± 3 mmHg, P = 0.043) during SHG 30%. Under baseline conditions, there was no significant difference in MSNA responses between the groups; however, when the BP response during exercise was equalized between the groups using nitroprusside, the 6R-BH4-treated group had a significantly lower MSNA response during RHG 20% (6R-BH4 vs. placebo, +12 ± 1 vs. +21 ± 2 bursts/min, P = 0.004) but not during SHG 30%. These findings suggest that 6R-BH4 ameliorates the augmented BP response during RHG 20% and SHG 30% in CKD patients. A reduction in reflex activation of SNA may contribute to the decreased exercise pressor response during RHG 20% but not during SHG 30% in CKD patients.

Regular aquatic exercise for chronic kidney disease patients: a 10-year follow-up study

Chronic kidney disease (CKD) patients not yet in dialysis can benefit from increased physical activity; however, the safety and outcomes of aquatic exercise have not been investigated in observational studies. The aim of this study was to analyze association of 10 years of regularly performed aquatic exercise with the study endpoint--that is, all-cause death or start of dialysis. Consecutive CKD patients were included in the study in January 2002. The exercise group (n=7) exercised regularly under the supervision of physiotherapist for 10 years; the control group (n=9), matched in terms of age and clinical parameters, remained sedentary. Low-intensity aerobic aquatic exercise was performed regularly twice a week; 32 weeks or more of exercise therapy sessions were conducted annually. None of the members of the aquatic exercise group reached dialysis or died in 10 years. In the sedentary control group, 55% reached the study endpoint--renal replacement therapy (n=2) or all-cause death (n=3). Occurrence of the study endpoint, compared using the exact multinomial test with unconditional margins, was statistically significantly different (P-value: 0.037) between the study groups. Regular supervised aquatic exercise arrested CKD progression. There was a statistically significant difference between the sedentary group and the exercise group in reaching renal replacement therapy or all-cause death in a follow-up time of 10 years.

Age and anemia management: relationship of hemoglobin levels with mortality might differ between elderly and nonelderly hemodialysis patients

BACKGROUND

The elderly hemodialyzed population is growing. However, little is known about the relationship between hemoglobin level and survival according to age. We investigated the effect of age on the relationship between hemoglobin and survival within the Japan Dialysis Outcomes and Practice Patterns Study (DOPPS) cohort.

METHODS

We enrolled the entire Japan DOPPS phases 3 and 4 population. Patients were divided by the age of 75 years into two groups. Cox's proportional hazard model was used with hemoglobin at every 4 months treated as a time-dependent variable. The interaction of age and hemoglobin was analyzed.

RESULTS

We included 3341 patients in the analyses. The primary outcome occurred in 567 patients during the median follow-up of 2.64 years. Hemoglobin of entire population was 10.3 ± 1.3 g/dL. The median of epoetin dose was 3000 IU/week. Interaction was found between ages stratified by the age of 75 years and hemoglobin values (P = 0.045) with use of Cox's proportional hazard model. The nonelderly population had poorer prognosis with hemoglobin <10 g/dL, while elderly population only with hemoglobin <9 g/dL. For both hemoglobin strata <9, ≥9 and <10 g/dL, interactions between age and hemoglobin were significant. Subgroup analysis indicated that interaction between age and Hb levels was observed only in the nondiabetic nephropathy group. Several sensitivity analyses demonstrated a similar trend with the original analyses and reinforced the robustness.

CONCLUSIONS

The elderly population might tolerate low hemoglobin levels. Our findings open the way for further investigation of individualized anemia management.

Abnormal neurocirculatory control during exercise in humans with chronic renal failure

Abnormal neurocirculatory control during exercise is one important mechanism leading to exercise intolerance in patients with both end-stage renal disease (ESRD) and earlier stages of chronic kidney disease (CKD). This review will provide an overview of mechanisms underlying abnormal neurocirculatory and hemodynamic responses to exercise in patients with kidney disease. Recent studies have shown that ESRD and CKD patients have an exaggerated increase in blood pressure (BP) during both isometric and rhythmic exercise. Subsequent studies examining the role of the exercise pressor reflex in the augmented pressor response revealed that muscle sympathetic nerve activity (MSNA) was not augmented during exercise in these patients, and metaboreflex-mediated increases in MSNA were blunted, while mechanoreflex-mediated increases were preserved under basal conditions. However, normalizing the augmented BP response during exercise via infusion of nitroprusside (NTP), and thereby equalizing baroreflex-mediated suppression of MSNA, an important modulator of the final hemodynamic response to exercise, revealed that CKD patients had an exaggerated increase in MSNA during isometric and rhythmic exercise. In addition, mechanoreflex-mediated control was augmented, and metaboreceptor blunting was no longer apparent in CKD patients with baroreflex normalization. Factors leading to mechanoreceptor sensitization, and other mechanisms underlying the exaggerated exercise pressor response, such as impaired functional sympatholysis, should be investigated in future studies.

The effects of oral L-carnitine supplementation on physical capacity and lipid metabolism in chronic hemodialysis patients

Background

It is well known that the physical activity in chronic hemodialysis patients decreases compared to that in normal subjects. In order to investigate the effects of L-carnitine on physical capacity and lipid metabolism, a cardiopulmonary exercise test using a bicycle ergometer was performed before and after 3 months of oral L-carnitine supplementation under double-blind conditions.

Methods and Results

A total of 20 stable outpatients undergoing hemodialysis treatment were randomly divided into 2 groups: controls receiving placebo and patients receiving 900 mg L-carnitine p.o. daily. The levels of free and acyl carnitine increased significantly from 22.9 ± 7.3 to 149.9 ± 51.8 μmol/l and from 16.0 ± 2.8 to 100.3 ± 50.2 μmol/l, respectively, in the L-carnitine group; however, there was no significant change in other plasma lipid profiles. The exercise time was decreased and the heart rate at the anaerobic threshold was increased in the control group 3 months after the study period, but there were no such changes observed in the L-carnitine group. The minute ventilation/CO₂ output slope increased significantly from 38.9 ± 7.8 to 43.8 ± 11.8 in the L-carnitine group. It has been speculated that a shift in the energy source occurs from carbohydrate to lipid, in terms of an increase of oxygen demand.

Conclusion

L-Carnitine supplementation might have some beneficial effects on the physical capacity of chronic hemodialysis patients due to the improvement of the lipid metabolism in the muscle.

Intradialytic cycling in children and young adults on chronic hemodialysis

BACKGROUND

Intradialytic exercise has been poorly investigated in pediatric patients on chronic hemodialysis (HD). The aim of this study was to assess the acceptability, safety and efficacy of intradialytic exercise in children and young adults on HD.

METHODS

The intradialytic exercise program consisted of 30-min sessions of intra-HD exercise using a cycloergometer two to three times a week for 3 months. Study endpoints were the 6-min walking test (6MWT) distances, lung function, number of stands in the chair test, lower extremity strength (LES), anthropometry, dietary intake, dialysis adequacy, incidence of symptomatic sessions, biochemistry and left ventricular mass index.

RESULTS

Ten pediatric patients with a median age of 15.3 (range 9.1-24.2) years were enrolled. Two of these underwent kidney transplantation; the remaining eight completed the study and adapted well to the exercise program. At the end of the 3-month study period, all patients had significantly improved results for the 6MWT (+4.9 %; p < 0.05), chair test (+19 %; p < 0.05) and LES (+29.3 %; p < 0.05). Pre-HD albumin, creatinine and total protein levels and post-HD creatinine levels had also significantly improved. The incidence of symptomatic sessions did not increase during the study period. No adverse events occurred.

CONCLUSIONS

Based on our results, we conclude that a 30-min exercise program of intradialytic cycling is feasible for the majority of pediatric patients on chronic HD and will be well accepted. Such an exercise program can lead to a significant improvement in the exercise capacity of this patient population.

Polymorphisms in the vitamin D receptor gene and parathyroid hormone gene in the development and progression of diabetes mellitus and its chronic complications, diabetic nephropathy and non-diabetic renal disease

BACKGROUND

We chose to study polymorphisms of vitamin D receptor gene (VDR) and parathyroid hormone genes (PTH), whose protein products significantly affect calciumphosphate metabolism in kidneys and are implicated in the pathogenesis of diabetes, which may also involve kidney damage.

METHODS

Distribution of genotypes of four polymorphisms in VDR gene, i.e, TaqI (rs731236), BsmI (rs1544410) ApaI (rs7975232), FokI (rs2228570) and two polymorphisms of PTH gene, i.e., DraII (rs6256), BstBI (rs6264), were studied using PCRRFLP. Examined groups consisted of 147 patients with diabetes (DM), 47 patients with nondiabetic renal disease (NDRD), 132 patients with diabetic nephropathy (DN) and 118 healthy subjects.

CONCLUSION

Comparison of DN group and healthy subjects identified statistically significant difference for the FokI polymorphism in VDR gene (P<10-4) and also for the BstBI polymorphism in PTH gene (P=0,023). Differences in DraII polymorphism distribution in PTH gene were statistically significant in each group of patients compared to healthy subjects. In DN patients, the BBFFAATt combination of VDR gene was more frequent than in healthy subjects (P=0,046), and the BbFFAaTt variant was more frequent than in DM2 patients (P=0,018). The BBDD haplotype of PTH gene seems to be a predisposing factor for diabetes itself (P=0,019).

[Renal replacement therapy for refractory heart failure]

After broad cardiological and nephrological evaluation and consideration of optimal conservative options according to national and international guidelines, renal replacement therapy might be helpful in patients with refractory heart failure even if they are not dialysis-dependent. This is even more important as renal failure is a strong predictor for mortality in patients with severe congestive heart failure (CHF) and CHF is one of the fastest growing morbidities in western countries. Although peritoneal dialysis (PD) is frequently used in patients with CHF its role remains unclear. Acute chronic volume overload in refractory CHF is still an unresolved clinical problem. In patients with acute heart and renal failure with need of management in an intensive care unit, extracorporeal ultrafiltration or a dialysis modality should be preferred. In patients with chronic refractory CHF, volume overload and renal failure, peritoneal dialysis should be the therapy of choice. Due to the limited data available, treatment and outcome parameters should be recorded in the registry of the German Society of Nephrology (http://www.herz-niere.de).

Exercício aeróbico durante a hemodiálise: relato de cinco anos de experiência

INTRODUÇÃO: Nos pacientes portadores de doença renal crônica (DRC) submetidos à hemodiálise (HD), o sedentarismo compromete a capacidade funcional e se associa a aumento da mortalidade por doenças cardiovasculares. Apesar da demonstração dos benefícios da prática de exercícios físicos para estes pacientes, poucos centros de diálise desenvolvem esta atividade. O objetivo deste estudo foi descrever a experiência de cinco anos de um programa de exercício aeróbico intradialítico, com ênfase na adesão e na segurança do procedimento. MÉTODOS: Foram incluídos pacientes adultos, de ambos os sexos, que participaram de um programa de exercícios realizado no período de agosto de 2004 a agosto de 2009. O exercício foi realizado nas duas horas iniciais da HD, empregando-se um cicloergômetro horizontal, sendo constituído de aquecimento, condicionamento e resfriamento. Foram realizadas análises descritivas dos dados coletados ao longo dos cinco anos do programa. RESULTADOS: No período de cinco anos, 34 pacientes (48,26 ± 11,44 anos; 20 mulheres) participaram do programa de exercício. Foram realizadas 3.077 sessões individuais de exercício aeróbico durante as sessões de HD. O tempo médio de participação no programa foi de 15,65 ± 13,86 meses e a aderência às sessões de exercício foi de 64,87 ± 19,47%. Apesar do registro de alguns episódios de hipotensão, sem repercussões hemodinâmicas significativas, não foram observadas complicações clínicas importantes. CONCLUSÃO: A realização de exercício aeróbico durante a sessão de HD é uma prática bem aceita pelos pacientes, segura e não acompanhada de complicações graves.

Performance evaluation of a turbidimetric cystatin C assay on different high-throughput platforms

OBJECTIVE

The goal with this study was to evaluate the analytical performance of a new cystatin C immunoassay (Tina-quant a Cystatin C, Roche Diagnostics GmbH). The evaluation was carried out at four centers according to a standardized protocol.

MATERIAL AND METHODS

The Tina-quant a Cystatin C is a latex particle-enhanced immunoturbidimetric assay. Roche cobas 6000, MODULAR ANALYTICS SWA and COBAS INTEGRA instruments were included in the study. Method comparison studies were carried out against two turbidimetric methods (Dako Cystatin C, Gentian Cystatin C), and one nephelometric method (Siemens N-Latex Cystatin C).

RESULTS

Linearity was proven throughout the measuring range from 0.4 to 8 mg/L. Within-run CVs ranged from 0.7-2.8%, and total CVs from 1.4-4.7 % (concentration range 0.6-3.9 mg/L). Comparable results were obtained with paired serum and Li-heparinate plasma samples. Good agreement was achieved in the comparisons between the Tina-quant a Cystatin C assay and the other commercially available cystatin C assays, two different turbidimetric methods (slope range 0.88-1.04, intercept < 0.17 mg/L, r > or = 0.993) and one nephelometric assay (slope range 0.90-1.05, intercept < 0.21 mg/L, r > or = 0.986).

CONCLUSIONS

The Tina-quant a Cystatin C assay was shown to be precise and accurate with proven linearity over the measuring range. Good comparability was obtained with other commercially available assays for the determination of cystatin C. The Tina-quant a Cystatin C assay is very well suited for clinical use on routine clinical chemistry analysers to detect renal dysfunction with a 24 h availability.

Effects of modality change and transplant on peak oxygen uptake in patients with kidney failure

BACKGROUND

Exercise capacity as measured by peak oxygen uptake (Vo₂(peak)) is low in hemodialysis patients. The present study assesses determinants of VO₂(peak) in patients with chronic kidney failure who either changed kidney replacement modality to frequent hemodialysis therapy or received a kidney transplant.

STUDY DESIGN

Cohort study with assessment at baseline and 6 months after modality change.

SETTING & PARTICIPANTS

Participants included nondiabetic individuals receiving conventional hemodialysis who: (1) remained on conventional hemodialysis therapy (n = 13), (2) changed to short daily hemodialysis therapy (n = 10), or (3) received a transplant (n = 5) and (4) individuals who underwent a pre-emptive transplant (n = 15). Additionally, 34 healthy controls were assessed at baseline only.

PREDICTOR

Modality change.

MEASUREMENT & OUTCOMES

Exercise capacity, assessed using the physiologic components of the Fick equation (Vo₂ = cardiac output × a-vo₂(dif), where a-vo₂(dif) is arterial to venous oxygen difference) was determined using measurement of Vo₂(peak) and cardiac output during symptom-limited exercise testing. Analysis of covariance was used to compare differences in changes in Vo₂(peak), cardiac output, heart rate, stroke volume, and a-vo₂(dif) at peak exercise between participants who remained on hemodialysis therapy and those who underwent transplant.

RESULTS

Transplant was the only modality change associated with a significant change in Vo₂(peak), occurring as a result of increased peak cardiac output and reflecting increased heart rate without a change in peak a-vo₂(dif) despite increased hemoglobin levels. There were no differences in participants who changed to daily hemodialysis therapy compared with those who remained on conventional hemodialysis therapy.

LIMITATIONS

Small nonrandomized study.

CONCLUSIONS

Vo₂(peak) increases significantly after kidney transplant, but not with daily hemodialysis; this improvement reflects increased peak cardiac output through increased peak heart rate. Despite statistical significance, the increase in Vo₂(peak) was not clinically significant, suggesting the need for interventions such as exercise training to increase Vo₂(peak) in all patients regardless of treatment modality.

Measurement of health-related quality of life in patients with chronic kidney disease in Japan with EuroQol (EQ-5D)

BACKGROUND

Chronic kidney disease (CKD) is a health-related quality-of-life (HRQOL) deteriorating disease which is not only a public health but also a socioeconomic problem. Interest in developing cost-effective interventions to control CKD has increased. The aim of this study was to measure HRQOL in terms of quality-adjustment weights for cost-effectiveness analysis using EQ-5D in patients with CKD. The relationships between the measured HRQOL and clinical indices/complications were also analyzed.

METHODS

EQ-5D, a generic preference-based instrument, was administered to 569 CKD outpatients at Tsukuba University Hospital between November and December 2008. The response rate was 94.4% (537/569). Data on sex, age, creatinine, hemoglobin, serum albumin and eGFR were obtained from the patients' records. Data on the presence of complications such as hypertension, diabetes, and history of cardiovascular disease (CVD) were also retrieved.

RESULTS

Measured quality-adjustment weights by the CKD stage were 0.940 (95% CI 0.915-0.965), 0.918 (0.896-0.940), 0.883 (0.857-0.909), 0.839 (0.794-0.884), and 0.798 (0.757-0.839) for stages 1-5, respectively. The decrease in weight was significant by ANOVA (P < 0.0001), and the weight for all stages was 0.885 (0.871-0.898). There was a positive relationship between hemoglobin/serum albumin and the weight. The presence of hypertension lowered the weight from 0.910 (0.885-0.936) to 0.874 (0.858-0.891), diabetes from 0.901 (0.886-0.917) to 0.840 (0.811-0.869), and CVD from 0.892 (0.878-0.906) to 0.783 (0.718-0.848).

CONCLUSIONS

HRQOL decreases with progression of CKD stage and/or presence of anemia, undernutrition, hypertension, diabetes, or history of CVD.

Non-invasive estimation of glomerular filtration rate (GFR). The Lund model: Simultaneous use of cystatin C- and creatinine-based GFR-prediction equations, clinical data and an internal quality check

Knowledge of glomerular filtration rate (GFR) is required to detect and follow impairment of renal function, to allow correct dosage of drugs cleared by the kidneys, and for the use of nephrotoxic contrast media. Correct determination of GFR requires invasive techniques, which are expensive, slow and not risk-free. Therefore, GFR-prediction equations based solely upon cystatin C or creatinine and anthropometric data or upon cystatin C, creatinine and anthropometric data have been developed. The combined prediction equations display the best diagnostic performance, but in several easily identifiable clinical situations (e.g. abnormal muscle mass, treatment with large doses of glucocorticoids) prediction equations based upon either cystatin C or creatinine are better than the combined equations. In Lund, where cystatin C has been used as a GFR-marker in the clinical routine since 1994, a strategy based upon this knowledge has therefore been developed. This comprises simultaneous use of a cystatin C-based and a creatinine-based GFR-prediction equation. If the GFRs predicted agree, the mean value is used as a reliable GFR-estimate. If the GFRs predicted do not agree, clinical data is evaluated to identify reasons for not using one of the two prediction equations and the GFR predicted by the other one is used. If no reasons for the difference in predicted GFRs are found, an invasive gold standard determination of GFR is performed. If the GFRs predicted agree for a patient, the creatinine value is reliably connected to a specific GFR and can be used to follow changes in GFR of that patient.

Inflammation and cachexia in chronic kidney disease

Chronic inflammation is associated with cachexia and increased mortality risk in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Inflammation suppresses appetite and causes the loss of protein stores. In CKD patients, increased serum levels of pro-inflammatory cytokines may be caused by reduced renal function, volume overload, oxidative or carbonyl stress, decreased levels of antioxidants, increased susceptibility to infection in uremia, and the presence of comorbid conditions. Cachexia is brought about by the synergistic combination of a dramatic decrease in appetite and an increase in the catabolism of fat and lean body mass. Pro-inflammatory cytokines act on the central nervous system to alter appetite and energy metabolism and to provide a signal-through the nuclear factor-kappaB and ATP-ubiquitin-dependent proteolytic pathways-that causes muscle wasting. Further research into the molecular pathways leading to inflammation and cachexia may lead to novel therapeutic therapies for this devastating and potentially fatal complication of chronic disease.

Exercise performance by hemodialysis patients: a review of the literature

Hemodialysis (HD) patients exhibit poor functional capacity and reduced quality of life as a result of the complications associated with end-stage renal disease (ESRD). A review of the literature indicates that regular physical activity can reduce the complications associated with ESRD by inducing adaptations in the cardiovascular, nervous, and musculoskeletal systems. In turn, this increases functional capacity and enhances quality of life in patients on HD. Hemodialysis patients can safely participate in a variety of exercise programs with minimal adverse effects. Intradialytic exercise programs that can incorporate aerobic and resistance exercise promote exercise adherence and should be encouraged on dialysis units.

Relation between alkaline phosphatase, serum phosphate, and all-cause or cardiovascular mortality

BACKGROUND

Higher levels of serum alkaline phosphatase (AlkP) are associated with excess mortality in dialysis patients, but whether AlkP is associated with adverse outcomes among people without kidney failure is unknown.

METHODS AND RESULTS

We first analyzed the association between AlkP and cardiovascular outcomes among 4115 participants with a previous myocardial infarction (the Cholesterol And Recurrent Events [CARE] study). Results were validated by analyzing the association between AlkP and mortality in an independent sample of 14,716 adults from the general US population (the Third National Health and Nutrition Examination Survey). A graded, independent association was noted between baseline tertile of AlkP and the adjusted hazard ratio of all-cause mortality in CARE participants (P(trend)=0.02). After adjustment for serum phosphate, hepatic enzymes, and other potential confounders, participants with AlkP in the highest tertile had an adjusted hazard ratio of 1.43 (95% confidence interval 1.08 to 1.89) compared with those in the lowest tertile. Multivariable-adjusted associations between higher AlkP and all-cause and cardiovascular mortality were present in the Third National Health and Nutrition Examination Survey (P(trend) across tertiles of AlkP=0.006 and 0.038, respectively). Findings from both CARE and the Third National Health and Nutrition Examination Survey were similar among individuals with and without evidence of kidney disease, defined by estimated glomerular filtration rate <60 mL min(-1) 1.73 m(-2).

CONCLUSIONS

We found an independent relation between higher levels of AlkP and adverse outcomes among survivors of myocardial infarction and in a general population sample. The excess risk of death was present in people without evidence of kidney disease and was particularly high among people with higher levels of both AlkP and serum phosphate.

Development and psychometric evaluation of the Dialysis patient-perceived Exercise Benefits and Barriers Scale

BACKGROUND

Perceptions of exercise benefits and barriers affect exercise behavior. Because of the clinical course and treatment, dialysis patients differ from the general population in their perceptions of exercise benefits and barriers, especially the latter. At present, no valid instruments for assessing perceived exercise benefits and barriers in dialysis patients are available.

OBJECTIVES

Our goal was to develop and test the psychometric properties of the Dialysis patient-perceived Exercise Benefits and Barriers Scale (DPEBBS).

METHODS

A literature review and two focus groups were conducted to generate the initial item pool. An expert panel examined the content validity. Then, 269 Chinese hemodialysis patients were recruited by convenience sampling. Exploratory and confirmatory factor analyses were used to test construct validity. Finally, internal consistency and test-retest reliability were assessed.

RESULTS

The expert panel determined that the content validity index was satisfactory. The final 24-item scale consisted of six factors explaining 57% of the total variance in the data. Confirmative factor analysis supported the six-factor structure and a higher-order model. Cronbach's alpha was 0.87 for the total scale, and 0.84 for test-retest reliability.

CONCLUSION

The DPEBBS was a valid and reliable instrument for evaluating dialysis patients' perceived benefits and barriers to exercise. The application value of this scale remains to be investigated by increasing the sample size and evaluating patients undergoing different dialysis modalities and coming from different regions and cultural backgrounds.

Implementation of the routine reporting of eGFR in Australia and New Zealand

The reporting of an eGFR (estimated glomerular filtration rate) with every requested serum creatinine concentration measurement has been successfully introduced as routine practice in Australia and New Zealand. This change in laboratory practice has been linked with a major educational initiative in the diagnosis and management of chronic kidney disease as well as standardization of a range of laboratory measurement and reporting issues. The process has been collaborative between renal physicians, chemical pathologists and laboratory scientists and their respective professional bodies, and the relevant decisions have been made collectively on the best available evidence. The initial guidelines were released in August 2005 and these have been followed up in 2007 with further recommendations to address issues arising since that time.

Glomerular Hyperfiltration and Albuminuria in Critically ILL Patients

Glomerular hyperfiltration and albuminuria are two pathological conditions that could alter renal drug elimination, but they have been rarely studied in a critical care setting.

The aims of this descriptive, prospective study performed on 89 critically ill patients are to determine rates of glomerular hyperfiltration (main objective) and albuminuria (secondary objective).

On admission, 17.9% of patients presented with glomerular hyperfiltration, climbing to rates as high as 30% during the first week of admission. Seventy-five percent showed albuminuria on admission, with rates remaining high throughout the week of the study.

Since glomerular hyperfiltration as well as albuminuria are frequent pathophysiological conditions in critical care patients, the implications that these phenomena may have regarding drug elimination need further evaluation.

Relation Between Red Blood Cell Distribution Width and Cardiovascular Event Rate in People With Coronary Disease

Background— Higher levels of red blood cell distribution width (RDW) may be associated with adverse outcomes in patients with heart failure. We examined the association between RDW and the risk of all-cause mortality and adverse cardiovascular outcomes in a population of people with coronary disease who were free of heart failure at baseline.

Methods and Results— We performed a post hoc analysis of data from the Cholesterol and Recurrent Events study. Baseline RDW was measured in 4111 participants who were randomized to receive pravastatin 40 mg daily or placebo and followed for a median of 59.7 months. We used Cox proportional hazards models to examine the association between RDW and adverse clinical outcomes. During nearly 60 months of follow-up, 376 participants died. A significant association was noted between baseline RDW level and the adjusted risk of all-cause mortality (hazard ratio per percent increase in RDW, 1.14; 95% confidence interval, 1.05 to 1.24). After categorization based on quartile of baseline RDW and further adjustment for hematocrit and other cardiovascular risk factors, a graded independent relation between RDW and death was observed ( P for trend=0.001). For instance, participants with RDW in the highest quartile had an adjusted hazard ratio for death of 1.78 (95% confidence interval, 1.28 to 2.47) compared with those in the lowest quartile. Higher levels of RDW were also associated with increased risk of coronary death/nonfatal myocardial infarction, new symptomatic heart failure, and stroke.

Conclusions— We found a graded independent relation between higher levels of RDW and the risk of death and cardiovascular events in people with prior myocardial infarction but no symptomatic heart failure at baseline.

Decreased maximal aerobic capacity in pediatric chronic kidney disease

Adult and pediatric patients with ESRD have impaired maximum oxygen consumption (VO(2) max), a reflection of the cardiopulmonary system's ability to meet increased metabolic demands. We sought to determine factors associated with decreased VO(2) max in pediatric patients with different stages of CKD. VO(2) max was measured using a standardized exercise testing protocol in patients with stage 2 to 4 chronic kidney disease (CKD) (n = 46), in renal transplant recipients (n = 22), in patients treated with maintenance hemodialysis (n = 12), and in age-matched healthy controls (n = 33). VO(2) max was similar between children with stage 2 CKD and controls, whereas lower VO(2) max was observed among children with stage 3 to 4 CKD, those treated with hemodialysis, and transplant recipients. In univariate analysis, VO(2) max was significantly associated with body mass index, resting heart rate, C-reactive protein, serum triglycerides, serum creatinine, and measures of diastolic function; no significant associations with left ventricular structure or systolic function were identified. In multivariate regression analysis, patient category versus control and the presence of diastolic dysfunction were independent predictors of lower VO(2) max. These results suggest that aerobic capacity is decreased in the early stages of CKD in children and that lower VO(2) max can be predicted by the presence of diastolic dysfunction, even if systolic function is normal.

Chronic kidney disease perspectives in Japan and the importance of urinalysis screening

There are racial differences in primary renal diseases for end-stage renal disease (ESRD) and the incidence and prevalence of cardiovascular disease (CVD). To reduce the number of patients with both ESRD and CVD, an effective screening method for CKD should be established. In Japan, screening with the urine dip-stick test for proteinuria has been used since 1972 targeting every child and worker and since 1983 for every resident over 40 years old. There are several reasons for continuing this screening program. First, the positive rate of proteinuria is high in the Japanese general population, especially subjects with neither hypertension nor diabetes. Most of these subjects have no symptoms, and the only sign of renal disease is asymptomatic urinary abnormalities. Second, the prevalence and incidence of glomerulonephritis, especially IgA nephropathy, are high in the Japanese and Asian races, and urinalysis is the only method for early detection of chronic glomerulonephritis. Third, 10-year survival of the ESRD patients due to glomerulonephritis was approximately twice that of ESRD patients due to diabetes and nephrosclerosis. Consequently, reducing the incidence of ESRD due to glomerulonephritis is one of the best ways to reduce the prevalence of ESRD. Furthermore, higher incidence of ESRD in Asian races than in Caucasians was reported. Proteinuria is known to be the best predictor for reducing renal function, and the urine dip-stick test for proteinuria is less expensive and is cost-effective. For an effective screening strategy to reduce the ESRD population in Japanese and Asians, universal screening with the urine dip-stick test for proteinuria could be one solution.

Exercício físico em pacientes dialisados

Pacientes portadores de doença renal crônica (DRC) submetidos a tratamento dialítico apresentam alterações físicas e psicológicas que predispõem ao sedentarismo. Nesta população, a prescrição rotineira de exercícios físicos não é uma prática freqüente, especialmente no nosso país. No entanto, alguns autores têm demonstrado que um programa de exercícios para estes pacientes contribui para o melhor controle da hipertensão arterial, da capacidade funcional, da função cardíaca, da força muscular e, conseqüentemente, da qualidade de vida. Além dos benefícios relacionados ao sistema cardiovascular, a realização do exercício traz benefícios secundários, pois quebra a monotonia do procedimento, melhora aderência e pode aumentar a eficácia da diálise. Na presente revisão, os autores discutem aspectos da realização de exercícios físicos em pacientes portadores de DRC em diálise e apresentam dados iniciais de sua experiência com a aplicação de exercícios supervisionados durante as sessões de hemodiálise.

Factors associated with peak oxygen uptake in hemodialysis patients awaiting renal transplantation

The preoperative evaluation of pulmonary function is important in renal transplantation candidates. Exercise capacity determined by peak oxygen uptake (peak Vo(2)) is a predictor of perioperative mortality and survival. The aim of this study was to determine the factors associated with the peak Vo(2) among renal transplantation candidates undergoing hemodialysis. Thirty patients with chronic renal failure including 14 women and 16 men of mean age 40.2 +/- 10.3 years had a mean duration of dialysis of 133.1 +/- 63.3 months and were awaiting renal transplantation. None of the patients had signs or symptoms of active infection or inflammation. Each patient underwent pulmonary function and symptom-limited cardiopulmonary exercise tests. Despite the absence of clinically evident inflammation, a malnutrition inflammation score was calculated for each patient to assess comorbid conditions and the risk of atherosclerosis. Demographic and laboratory parameters were obtained from hospital records. The peak Vo(2) was positively correlated with the serum triglyceride level and negatively correlated with serum ferritin level and malnutrition inflammation score. On multiple linear regression analyses, which were performed to assess the potential predictors of the peak Vo(2), the malnutrition inflammation score was the only variable that independently correlated with the peak Vo(2) in hemodialysis patients awaiting renal transplantation. In conclusion, peak Vo(2) is associated with markers of nutrition and the malnutrition inflammation score. We suggest that chronic malnutrition and silent inflammation may be responsible for the preoperative decreased exercise capacity in renal transplantation candidates undergoing hemodialysis.

Interleukin-18, the Metabolic Syndrome, and Subclinical Atherosclerosis

OBJECTIVE

Although IL-18 promotes atherogenesis in animal studies and predicts cardiovascular risk in humans, it is unknown whether elevated IL-18 levels are associated with coronary atherosclerosis in the general population.

METHODS AND RESULTS

IL-18 plasma levels were determined by ELISA in 2231 subjects from the Dallas Heart Study. In univariable analysis, IL-18 levels associated with traditional cardiovascular risk factors and particularly with components of the metabolic syndrome (MS, P<0.01 for trend across the number of MS components); IL-18 also associated with coronary artery calcium (CAC) scores measured by electron beam computed tomography and aortic plaque measured by MRI (P<0.01 for each). In multivariable analyses, IL-18 remained associated with multiple components of the MS but not with CAC or aortic plaque.

CONCLUSIONS

In a large population-based sample, elevated IL-18 plasma levels associated with risk factors for atherosclerosis and with the metabolic syndrome. The association between IL-18 and atherosclerosis diminished after accounting for traditional cardiovascular risk factors. These data suggest that IL-18 does not add independently to detection of atherosclerotic burden in asymptomatic individuals.