Physical activity and nutrition in chronic kidney disease.

PURPOSE OF REVIEW: Lifestyle intervention is considered a cornerstone in chronic kidney disease management and has been recommended in different international or regional clinical practice guidelines in chronic kidney disease. However, evidence was largely based on the general population. Here we summarized the latest evidence supporting lifestyle intervention in chronic kidney disease. RECENT FINDINGS: Both observational cohort studies as well as randomized controlled trials have demonstrated health benefits with more physical activity in chronic kidney disease. There are compelling observational data supporting different health and kidney benefits with a healthy dietary pattern rich in fruits and vegetables, whole grains, plant-based foods and low in salt, low in sugar, saturated fat, red meat and ultraprocessed foods, a plant-based diet or Mediterranean diet in chronic kidney disease population. Clinical and epidemiologic studies also showed that higher 24 h urine potassium excretion (as proxy of higher dietary potassium intake) may be associated with lower blood pressure, better kidney outcomes and lower mortality in chronic kidney disease population. Randomized controlled trials also suggested that salt substitutes improved blood pressure control, reduced all-cause death and cardiovascular event risk in the general population compared with regular salt. SUMMARY: Accumulating evidence supports the current recommendation of encouraging physical activity and promoting a healthy dietary pattern in chronic kidney disease patients. Whether potassium needs restriction in chronic kidney disease diet requires further review. The safety versus benefits of salt substitutes in patients with moderate and advanced chronic kidney disease warrants further investigation.

Circulating endotoxin and inflammation: associations with fitness, physical activity and the effect of a 6-month programme of cycling exercise during haemodialysis.

BACKGROUND: Intradialytic cycling (IDC) may provide cardiovascular benefits to individuals receiving haemodialysis, but the exact mechanism behind these improvements remains unclear. The primary aim of this study was to investigate the effect of a 6-month programme of IDC on circulating endotoxin (secondary analysis from the CYCLE-HD trial). Secondary aims were to investigate changes in circulating cytokines [interleukin-6 (IL-6), IL-10, tumour necrosis factor-α, C-reactive protein (CRP) and the IL-6:IL-10 ratio] and their associations with physical activity, fitness and cardiovascular outcomes. METHODS: Participants were randomized to either a 6-month programme of IDC (thrice weekly, moderate intensity cycling at a rating of perceived exertion of 12-14) in addition to usual care (n = 46) or usual care only (control group; n = 46). Outcome measures were obtained at baseline and then again at 6 months. RESULTS: There was no significant (P = 0.137) difference in circulating endotoxin between groups at 6 months (IDC group: 0.34 ± 0.08 EU/mL; control group: 0.37 ± 0.07 EU/mL). There were no significant between-group differences in any circulating cytokine following the 6-month programme of IDC. Higher levels of physical activity and fitness were associated with lower levels of endotoxin, IL-6, CRP and IL-6:IL-10 ratio. CONCLUSIONS: Our data show no change in circulating endotoxin or cytokines following a 6-month programme of IDC. However, higher levels of physical activity outside of haemodialysis were associated with lower levels of inflammation.

Associations between physical activity levels and renal recovery following acute kidney injury stage 3: a feasibility study.

BACKGROUND: Acute kidney injury (AKI) can lead to chronic kidney disease, which results in poor long-term outcomes. There is plausibility that increased levels of physical activity may promote renal recovery post-AKI. This study aimed to investigate associations between physical activity levels and renal recovery following stage 3 AKI, and to assess the feasibility of measuring physical activity levels in this population. METHODS: Forty One hospitalised patients with AKI stage 3 were enrolled. Serum creatinine and estimated glomerular filtration rate (eGFR) were collected at 12 months prior to the development of AKI, during the hospital admission when the episode of AKI stage 3 occurred, and at 1-, 3- and 6-months post discharge. All participants completed the General Practice Activity Questionnaire (GPPAQ) to assess physical activity levels. A pedometer was also worn for 7 days immediately following discharge and at 6-months post discharge to ascertain an average daily step count. Feasibility outcomes including eligibility, recruitment and retention rates, and losses to follow up were also assessed. RESULTS: The average (± SD) baseline eGFR and median (IQR) serum creatinine was 71 ± 20 mL/min/1.73m2 and 85 (49) µmol/L respectively. A threefold increase in creatinine occurred during hospitalisation 436 (265) µmol/L. Greatest renal recovery occurred prior to discharge, with recovery continuing for a further three months. Inactive individuals (low GPPAQ scores) had consistently higher serum creatinine values compared to those who were active: 1 months 122 (111) µmol/L vs 70 (0) µmol/L, 6 months 112 (57) µmol/L vs 68 (0) µmol/L. Individuals with higher step counts also displayed better renal recovery 6-months post discharge (r = -0.600, p = 0.208). CONCLUSIONS: Higher levels of physical activity are associated with improved renal recovery after 6- months following an episode of stage 3 AKI. A future randomised controlled trial is feasible and would be required to confirm these initial findings.

Intradialytic cycling does not exacerbate microparticles or circulating markers of systemic inflammation in haemodialysis patients.

PURPOSE: Patients receiving haemodialysis (HD) display elevated circulating microparticle (MP) concentration, tissue factor (TF) expression and markers of systemic inflammation, though regular intradialytic cycling (IDC) may have a therapeutic effect. This study investigated the impact of regular, moderate-intensity IDC on circulating MPs and inflammatory markers in unit-based HD patients. METHODS: Patients were cluster-randomised to intervention (n = 20, age: 51.4 ± 18.1 years, body mass: 77.6 ± 18.3 kg, mean ± SD) or no-exercise control (n = 20, 56.8 ± 14.0 years, 80.5 ± 26.5 kg). Intervention participants completed 30 min of moderate intensity (rating of perceived exertion [RPE] of 12-14) IDC, thrice weekly for 6 months. Pre-dialysis venous blood samples were obtained at 0, 3 and 6 months. Circulating MP phenotypes, cytokines, chemokine and MP TF expression were quantified using flow cytometry and cytometric bead array assays. RESULTS: Despite high exercise compliance (82%), no IDC-dependent effects were observed for any MP, cytokine or chemokine measure (p ≥ 0.051, ηρ2 ≤ 0.399) other than TNF-α (p = 0.001, ηρ2 = 0.186), though no significance was revealed upon post hoc analysis. CONCLUSION: Six months of regular, moderate-intensity IDC had no effect on MPs, cytokines or chemokines. This suggests that the exercise did not exacerbate thrombotic or inflammatory status, though further functional assays are required to confirm this. TRIAL REGISTRATION: ISRCTN1129707, prospectively registered on 05/03/2015.

A Comparison of Dietary Intake Between Individuals Undergoing Maintenance Hemodialysis in the United Kingdom and China.

OBJECTIVE: Protein-energy wasting is highly prevalent in people with end-stage kidney disease receiving regular hemodialysis. Currently, it is unclear what the optimal nutritional recommendations are, which is further complicated by differences in dietary patterns between countries. The aim of the study was to understand and compare dietary intake between individuals receiving hemodialysis in Leicester, UK and Nantong, China. METHODS: The study assessed 40 UK and 44 Chinese participants' dietary intake over a period of 14 days using 24-hour diet recall interviews. Nutritional blood parameters were obtained from medical records. Food consumed by participants in the UK and China was analyzed using the Nutritics and Nutrition calculator to quantify nutritional intake. RESULTS: Energy and protein intake were comparable between UK and Chinese participants, but with both below the recommended daily intake. Potassium intake was higher in UK participants compared to Chinese participants (2,115 [888] versus 1,159 [861] mg/d; P < .001), as was calcium (618 [257] versus 360 [312] mg/d; P < .001) and phosphate intake (927 [485] versus 697 [434] mg/d; P = .007). Vitamin C intake was lower in UK participants compared to their Chinese counterparts (39 [51] versus 64 [42] mg/d; P = .024). Data are reported here as median (interquartile range). CONCLUSION: Both UK and Chinese hemodialysis participants have insufficient protein and energy in their diet. New strategies are required to increase protein and energy intakes. All participants had inadequate daily intake of vitamins C and D; there may well be a role in the oral supplementation of these vitamins, and further studies are urgently needed.

A randomized controlled trial to investigate the effects of intra-dialytic cycling on left ventricular mass.

Cardiovascular disease is the leading cause of death for patients receiving hemodialysis. Since exercise mitigates many risk factors which drive cardiovascular disease for these patients, we assessed effects of a program of intra-dialytic cycling on left ventricular mass and other prognostically relevant measures of cardiovascular disease as evaluated by cardiac MRI (the CYCLE-HD trial). This was a prospective, open-label, single-blinded cluster-randomized controlled trial powered to detect a 15g difference in left ventricular mass measured between patients undergoing a six-month program of intra-dialytic cycling (exercise group) and patients continuing usual care (control group). Pre-specified secondary outcomes included measures of myocardial fibrosis, aortic stiffness, physical functioning, quality of life and ventricular arrhythmias. Outcomes were analyzed as intention-to-treat according to a pre-specified statistical analysis plan. Initially, 130 individuals were recruited and completed baseline assessments (65 each group). Ultimately, 101 patients completed the trial protocol (50 control group and 51 exercise group). The six-month program of intra-dialytic cycling resulted in a significant reduction in left ventricular mass between groups (-11.1g; 95% confidence interval -15.79, -6.43), which remained significant on sensitivity analysis (missing data imputed) (-9.92g; 14.68, -5.16). There were significant reductions in both native T1 mapping and aortic pulse wave velocity between groups favoring the intervention. There was no increase in either ventricular ectopic beats or complex ventricular arrhythmias as a result of exercise with no significant effect on physical function or quality of life. Thus, a six-month program of intradialytic cycling reduces left ventricular mass and is safe, deliverable and well tolerated.

The reliability and feasibility of non-contrast adenosine stress cardiovascular magnetic resonance T1 mapping in patients on haemodialysis.

BACKGROUND: Identifying coronary artery disease (CAD) in patients with end-stage renal disease (ESRD) is challenging. Adenosine stress native T1 mapping with cardiovascular magnetic resonance (CMR) may accurately detect obstructive CAD and microvascular dysfunction in the general population. This study assessed the feasibility and reliability of adenosine stress native T1 mapping in patients on haemodialysis. METHODS: The feasibility of undertaking rest and adenosine stress native T1 mapping using the single-shot Modified Look-Locker inversion recovery (MOLLI) sequence was assessed in 58 patients on maintenance haemodialysis using 3 T CMR. Ten patients underwent repeat stress CMR within 2 weeks for assessment of test-retest reliability of native T1, stress T1 and delta T1 (ΔT1). Interrater and intrarater agreement were assessed in 10 patients. Exploratory analyses were undertaken to assess associations between clinical variables and native T1 values in 51 patients on haemodialysis. RESULTS: Mean age of participants was 55 ± 15 years, 46 (79%) were male, and median dialysis vintage was 21 (8; 48) months. All patients completed the scan without complications. Mean native T1 rest, stress and ΔT1 were 1261 ± 57 ms, 1297 ± 50 ms and 2.9 ± 2.5%, respectively. Interrater and intrarater agreement of rest T1, stress T1 and ΔT1 were excellent, with intraclass correlation coefficients (ICC) > 0.9 for all. Test-retest reliability of rest and stress native T1 were excellent or good (CoV 1.2 and 1.5%; ICC, 0.79 and 0.69, respectively). Test-retest reliability of ΔT1 was moderate to poor (CoV 27.4%, ICC 0.55). On multivariate analysis, CAD, diabetes mellitus and resting native T1 time were independent determinants of ΔT1 (ß = - 0.275, p = 0.019; ß = - 0.297, p = 0.013; ß = - 0.455; p < 0.001, respectively). CONCLUSIONS: Rest and adenosine stress native T1 mapping is feasible and well-tolerated amongst patients with ESRD on haemodialysis. Although rater agreement of the technique is excellent, test-retest reliability of ΔT1 is moderate to poor. Prospective studies should evaluate the relationship between this technique and established methods of CAD assessment and association with outcomes.

Exercise as a therapeutic option for acute kidney injury: mechanisms and considerations for the design of future clinical studies.

Acute kidney injury (AKI) is a known risk factor for chronic kidney disease (CKD) and end stage kidney disease (ESKD). The progression from AKI to CKD, despite being well recognised, is not completely understood, although sustained inflammation and fibrosis are implicated. A therapeutic intervention targeting the post AKI stage could reduce the progression to CKD, which has high levels of associated morbidity and mortality. Exercise has known anti-inflammatory effects with animal AKI models demonstrating its use as a therapeutic agent in abrogating renal injury. This suggests the use of an exercise rehabilitation programme in AKI patients following discharge could attenuate renal damage and improve long term patient outcomes. In this review article we outline considerations for future clinical studies of exercise in the AKI population.

The Efficacy of Prebiotic, Probiotic, and Synbiotic Supplementation in Modulating Gut-Derived Circulatory Particles Associated With Cardiovascular Disease in Individuals Receiving Dialysis: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

OBJECTIVE: This systematic review and meta-analyses provide an up-to-date synthesis on the effects of supplementation on circulating levels of toxic metabolites, markers of uremia and inflammation, blood lipids, and other clinical outcomes. METHODS: Seventeen databases were searched, supplemented with internet and hand searching. Randomized controlled trials of adult end-stage renal-disease individuals receiving either hemodialysis or peritoneal dialysis were eligible. Trials were restricted to those which had administered a prebiotic, probiotic, or synbiotic as an oral supplement. Primary outcomes were measures of circulating endotoxin, indoxyl-sulphate, and p-cresyl sulfate. RESULTS: Twenty-one trials were eligible (1152 randomized participants), of which 16 trials were considered to have a high risk of bias. The number of trials available for meta-analysis varied for each primary outcome. Synthesized data indicated that supplementation significantly reduced circulating levels of endotoxin (standardized mean difference, -0.61; 95% confidence interval, -1.03 to -0.20; P = .004; I2 = 0%), indoxyl-sulphate (-0.34; -0.64 to -0.04; P = .02; I2 = 0%), and p-cresyl sulfate (-0.34; -0.61 to -0.07; P = .01; I2 = 0%). For secondary outcomes, supplementation significantly reduced gastrointestinal symptoms (-0.54; -1.02 to -0.07; P = .02; I2 = 0%). CONCLUSIONS: Supplementation reduces toxic metabolites associated with cardiovascular disease and mortality in individuals receiving dialysis. However, the majority of trials included were low in quality.

The effect of bovine colostrum supplementation on intestinal injury and circulating intestinal bacterial DNA following exercise in the heat.

PURPOSE: Exercise-induced changes in intestinal permeability are exacerbated in the heat. The aim of this study was to determine the effect of 14 days of bovine colostrum (Col) supplementation on intestinal cell damage (plasma intestinal fatty acid-binding protein, I-FABP) and bacterial translocation (plasma bacterial DNA) following exercise in the heat. METHODS: In a double-blind, placebo-controlled, crossover design, 12 males completed two experimental arms (14 days of 20 g/day supplementation with Col or placebo, Plac) consisting of 60 min treadmill running at 70% maximal aerobic capacity (30 °C, 60% relative humidity). Blood samples were collected pre-exercise (Pre-Ex), post-exercise (Post-Ex) and 1 h post-exercise (1 h Post-Ex) to determine plasma I-FABP concentration, and bacterial DNA (for an abundant gut species, Bacteroides). RESULTS: Two-way repeated measures ANOVA revealed an arm × time interaction for I-FABP (P = 0.005, with greater Post-Ex increase in Plac than Col, P = 0.01: Plac 407 ± 194% of Pre-Ex vs Col, 311 ± 134%) and 1 h Post-Ex (P = 0.036: Plac 265 ± 80% of Pre-Ex vs Col, 229 ± 56%). There was no interaction (P = 0.904) but there was a main effect of arm (P = 0.046) for plasma Bacteroides/total bacterial DNA, with lower overall levels evident in Col. CONCLUSION: This is the first investigation to demonstrate that Col can be effective at reducing intestinal injury following exercise in the heat, but exercise responses (temporal pattern) of bacterial DNA were not influenced by Col (although overall levels may be lower).

Effects of intradialytic cycling exercise on exercise capacity, quality of life, physical function and cardiovascular measures in adult haemodialysis patients: a systematic review and meta-analysis.

Background: Intradialytic cycling (IDC), delivered during haemodialysis (HD), has the potential to improve many health issues. This systematic review and meta-analysis examine the evidence on the effects of IDC on exercise capacity, quality of life (QoL), physical function and cardiovascular health. Methods: Twenty-four databases were searched alongside Internet and hand searching, and consultation with experts. Eligibility criteria were cluster randomized, randomized and quasi-randomized controlled trials (RCTs) of IDC versus usual care in prevalent adult HD patients. Primary outcome measures were exercise capacity (VO2 peak and field tests) and QoL. Secondary measures were cardiac and physical function. Results: Thirteen RCTs were eligible. Eight provided data for use in meta-analyses, which indicated no significant change in VO2 peak (mean difference, MD 1.19 mL/kg/min, 95% confidence interval -1.15 to 3.52, P = 0.3), physical (mean change, MC 1.97, -8.27 to 12.22, P = 0.7) or mental component (MC 3.37, -7.94 to 14.68, P = 0.6) summary scores of the Medical Outcomes Short Form 36, pulse wave velocity (MD -0.57 m/s, -1.55 to 0.41, P = 0.4), systolic (MD -2.28 mmHg, -14.46 to 9.90, P = 0.7) or diastolic blood pressure (MD 2.25 mmHg, -3.01 to 7.50, P = 0.4) following IDC. IDC, however, leads to an improvement in performance on the 6-min walk test (MD 87.84 m, 39.60-136.09, P = 0.0004). All included studies were considered to have high risk of bias. Conclusions: There is insufficient evidence demonstrating whether cycling exercise during HD improves patient outcomes. High-quality, adequately powered RCTs of IDC are required.

Native T1 mapping: inter-study, inter-observer and inter-center reproducibility in hemodialysis patients.

BACKGROUND: Native T1 mapping is a cardiovascular magnetic resonance (CMR) technique that associates with markers of fibrosis and strain in hemodialysis patients. The reproducibility of T1 mapping in hemodialysis patients, prone to changes in fluid status, is unknown. Accurate quantification of myocardial fibrosis in this population has prognostic potential. METHODS: Using 3 Tesla CMR, we report the results of 1) the inter-study, inter-observer and intra-observer reproducibility of native T1 mapping in 10 hemodialysis patients; 2) inter-study reproducibility of left ventricular (LV) structure and function in 10 hemodialysis patients; 3) the agreement of native T1 map and native T1 phantom analyses between two centres in 20 hemodialysis patients; 4) the effect of changes in markers of fluid status on native T1 values in 10 hemodialysis patients. RESULTS: Inter-study, inter-observer and intra-observer variability of native T1 mapping were excellent with co-efficients of variation (CoV) of 0.7, 0.3 and 0.4% respectively. Inter-study CoV for LV structure and function were: LV mass = 1%; ejection fraction = 1.1%; LV end-diastolic volume = 5.2%; LV end-systolic volume = 5.6%. Inter-centre variability of analysis techniques were excellent with CoV for basal and mid-native T1 slices between 0.8-1.2%. Phantom analyses showed comparable native T1 times between centres, despite different scanners and acquisition sequences (centre 1: 1192.7 ± 7.5 ms, centre 2: 1205.5 ± 5 ms). For the 10 patients who underwent inter-study testing, change in body weight (Δweight) between scans correlated with change in LV end-diastolic volume (ΔLVEDV) (r = 0.682;P = 0.03) representing altered fluid status between scans. There were no correlations between change in native T1 between scans (ΔT1) and ΔLVEDV or Δweight (P > 0.6). Linear regression confirmed ΔT1 was unaffected by ΔLVEDV or Δweight (P > 0.59). CONCLUSIONS: Myocardial native T1 is reproducible in HD patients and unaffected by changes in fluid status at the levels we observed. Native T1 mapping is a potential imaging biomarker for myocardial fibrosis in patients with end-stage renal disease.

Intestinal fatty acid-binding protein and gut permeability responses to exercise.

PURPOSE: Intestinal cell damage due to physiological stressors (e.g. heat, oxidative, hypoperfusion/ischaemic) may contribute to increased intestinal permeability. The aim of this study was to assess changes in plasma intestinal fatty acid-binding protein (I-FABP) in response to exercise (with bovine colostrum supplementation, Col, positive control) and compare this to intestinal barrier integrity/permeability (5 h urinary lactulose/rhamnose ratio, L/R). METHODS: In a double-blind, placebo-controlled, crossover design, 18 males completed two experimental arms (14 days of 20 g/day supplementation with Col or placebo, Plac). For each arm participants performed two baseline (resting) intestinal permeability assessments (L/R) pre-supplementation and one post-exercise following supplementation. Blood samples were collected pre- and post-exercise to determine I-FABP concentration. RESULTS: Two-way repeated measures ANOVA revealed an arm × time interaction for L/R and I-FABP (P < 0.001). Post hoc analyses showed urinary L/R increased post-exercise in Plac (273% of pre, P < 0.001) and Col (148% of pre, P < 0.001) with post-exercise values significantly lower with Col (P < 0.001). Plasma I-FABP increased post-exercise in Plac (191% of pre-exercise, P = 0.002) but not in the Col arm (107%, P = 0.862) with post-exercise values significantly lower with Col (P = 0.013). Correlations between the increase in I-FABP and L/R were evident for visit one (P = 0.044) but not visit two (P = 0.200) although overall plots/patterns do appear similar for each. CONCLUSION: These findings suggest that exercise-induced intestinal cellular damage/injury is partly implicated in changes in permeability but other factors must also contribute.

Novel cardiac nuclear magnetic resonance method for noninvasive assessment of myocardial fibrosis in hemodialysis patients.

Left ventricular hypertrophy and myocardial fibrosis frequently occur in patients with end-stage renal disease receiving hemodialysis therapy and are associated with poor prognosis. Native T1 mapping is a novel cardiac magnetic resonance imaging technique that measures native myocardial T1 relaxation, a surrogate of myocardial fibrosis. Here we compared global and segmental native myocardial T1 time and global longitudinal, circumferential and segmental strain, and cardiac function of 35 hemodialysis patients and 22 control individuals. The median native global T1 time was significantly higher in the hemodialysis than the control group (1270 vs. 1085 ms), with the septal regions of hemodialysis patients having significantly higher median T1 times than nonseptal regions (1293 vs. 1252 ms). The mean peak global circumferential strain and global longitudinal strain were both significantly reduced in hemodialysis patients compared with controls (-18.3 vs. -21.7 and -16.1 vs. -20.4, respectively). Systolic strain was also significantly reduced in the septum compared with the nonseptal myocardium in hemodialysis patients (-16.2 vs. -21.9) but not in control subjects. Global circumferential strain and longitudinal strain significantly correlated with global native T1 values (r = 0.41 and 0.55, respectively), and the septal native T1 significantly correlated with the septal systolic strain (r = 0.46). Thus, myocardial fibrosis may be assessed noninvasively with native T1 mapping; the interventricular septum appears to be particularly prone to the development of fibrosis in hemodialysis patients.

Lifestyle interventions delivered by eHealth in chronic kidney disease: A scoping review.

A method of overcoming barriers associated with implementing lifestyle interventions in CKD may be through the use of eHealth technologies. The aim of this review was to provide an up-to-date overview of the literature on this topic. Four bibliographical databases, two trial registers, and one database for conference proceedings were searched from inception to August 2023. Studies were eligible if they reported a lifestyle intervention using eHealth technologies. A narrative synthesis of the findings from the included studies structured around the type of eHealth intervention was presented. Where a sufficient number of studies overlapped in terms of the type of intervention and outcome measure these were brought together in a direction of effect plot. There were 54 included articles, of which 23 were randomised controlled trials (RCTs). The main component of the intervention for the included studies was mobile applications (n = 23), with the majority being in the dialysis population (n = 22). The majority of eHealth interventions were reported to be feasible and acceptable to participants. However, there was limited evidence that they were efficacious in improving clinical outcomes with the exception of blood pressure, intradialytic weight gain, potassium, and sodium. Although eHealth interventions appear acceptable and feasible to participants, there is insufficient evidence to make recommendations for specific interventions to be implemented into clinical care. Properly powered RCTs which not only demonstrate efficacy, but also address barriers to implementation are needed to enhance widespread adoption.

Associations of health literacy with self-management behaviours and health outcomes in chronic kidney disease: a systematic review.

INTRODUCTION: Low health literacy is widely reported in people with chronic kidney disease (CKD) and has been associated with reduced disease self-management, poor health outcomes, increased mortality and poorer quality of life. However, these associations are still not well understood. METHODS: Electronic-based systematic searches were performed to identify studies examining associations between health literacy and self-management behaviours and/or health outcomes in patients with CKD. A tabular and narrative synthesis of the data was performed. Meta-analysis was not appropriate due to the heterogeneity of study designs and methods. RESULTS: Searches identified 48 studies that met the inclusion criteria. A total of 41 published articles, six conference abstracts, and one thesis were included. Of the 48 studies, 11 were cohort and 37 were cross-sectional. In total there were 25,671 patients; 16,952 from cohort studies. Median study sample size was 159 (IQR 92-275). Study quality was high (5), moderate (24) and poor (19). Thirteen measures of health literacy were used. Despite the limitations of the available evidence, there appear to be consistent relationships between higher health literacy and favourable self-management behaviours for patients with CKD. Definitive relationships between health literacy and patient outcomes are far less clear and remain incompletely understood. DISCUSSION: Conclusive evidence describing a causal link between health literacy and patient outcomes remains limited, but for many outcomes, a consistent association is described. In addition to associations with mortality, hospitalisation and clinical events, there were consistent associations between health literacy and favourable self-management behaviours which could support the development of patient education aimed at improving health literacy.

The effect of extended hemodialysis on nutritional parameters: a systematic review.

OBJECTIVE: This systematic review provides an up-to-date synthesis on the effects of extended hemodialysis on nutritional outcomes. DESIGN AND METHODS: Ten databases were searched. Inclusion criteria were: randomised and non-randomised studies of extended hemodialysis (defined by > 15 h/week) with a comparator group which received conventional in-centre hemodialysis (usually ≤ 12 h per week). Outcomes of interest included lean body mass, protein and carbohydrate intake, body mass index, dry lean mass, water-soluble vitamin levels, serum levels of appetite hormones, and nutritional status as assessed by the PEW and SGA scoring tools. RESULTS: Five studies were eligible. All investigated extended nocturnal hemodialysis (one with the addition of short daily), three were in-centre and two were at home. Range of duration for the included studies was 2-18 months. These studies reported data on lean body mass, protein and carbohydrate intake, body mass index, dry lean mass and water-soluble vitamin levels. There was insufficient homogeneity between the studies to meta-analyse the data. Extended hemodialysis had no significant effects on any of the reported outcomes except for lean body mass, where a significant increase was found, and water-soluble vitamin levels, where deficiency was identified in one of the included studies. CONCLUSION: There is currently no evidence to suggest that extended hemodialysis modalities impact nutritional parameters, although the quality of the available evidence is low.