Handgrip Strength Index: A Novel Parameter Which Quantifies Clinical Weakness in People on Haemodialysis.

OBJECTIVE: The muscle strength in people on haemodialysis is associated with nutritional status, quality of life, functional independence, and survival. Handgrip Strength (HGS) is simple to measure, but clinical interpretation is limited by the lack of reference ranges for a haemodialysis population. This study aims to define a novel parameter, HGS index, which quantifies degree of clinical weakness specific to a haemodialysis population and to test if this predicts survival. METHODS: In a cross-sectional single center study HGS was measured in stable participants on haemodialysis. HGS in the well-nourished subgroup, was used to develop a predictive equation for "expected" HGS according to demographic variables. This then was compared to observed HGS resulting in HGS index (%), an individualized parameter indicating weakness due to clinical variables while accounting for demographic contributors to strength. The association between HGS index and survival was explored in all participants. RESULTS: Among 427 well-nourished individuals on haemodialysis, HGS was strongly associated with demographic variables and predicted in males by the equation: HGS (kg) = 0.38∗height (cm) - 0.31∗age (years) - 18, and in females by the equation: HGS (kg) = 0.25∗height (cm) - 0.11∗age (years) - 16. Among 547 participants (22% with protein energy wasting), lower HGS index was associated with diabetes (P = .004), lower body mass index (BMI) (P = .005), lower albumin (P = .033), and longer dialysis vintage (P = .007). Over a mean observation period of 2.8 years, quintile of HGS index was strongly associated with survival (P = .023), and in a Cox proportional hazards model, the independent predictors of mortality were age, albumin, BMI and HGS index. CONCLUSION: HGS index, defined as observed relative to expected HGS, is an individualized measure of clinical weakness. It is a novel parameter which independently predicts survival. HGS index improves the detection of clinically relevant muscle weakness in people on haemodialysis, opening up the possibility of earlier, individualized interventions, and improving outcomes in this vulnerable group.

Oral sodium bicarbonate in people on haemodialysis: a randomised controlled trial.

BACKGROUND: Adverse events and mortality tend to cluster around dialysis sessions, potentially due to the impact of the saw-toothed profile of uraemic toxins such as potassium, peaking pre-dialysis and rapidly dropping during dialysis. Acidosis could be contributing to this harm by exacerbating a rise in potassium. The objectives of this study were to investigate the effects of oral bicarbonate treatment on reducing inter-dialytic potassium gain as well as other clinical consequences of preserving muscle mass and function and reducing intradialytic arrhythmia risk in people on haemodialysis. METHODS: Open-label randomised controlled trial in a single-centre (London, UK). Forty-three clinically stable adults on haemodialysis were recruited, with a 6 month average pre-dialysis serum bicarbonate level < 22 mmol/l and potassium > 4 mmol/l. Thirty-three participants completed the study. Oral sodium bicarbonate tablets titrated up to a maximum of 3 g bd (6 g total) in intervention group for 12 weeks versus no treatment in the control group. Outcomes compared intervention versus non-intervention phases in the treated group and equivalent time points in the control group: pre- and post-dialysis serum potassium; nutritional assessments: muscle mass and handgrip strength and electrocardiograms (ECGs) pre and post dialysis. RESULTS: Participants took an average of 3.7 ± 0.5 g sodium bicarbonate a day. In the intervention group, inter-dialytic potassium gain was reduced from 1.90 ± 0.60 to 1.69 ± 0.49 mmol/l (p = 0.032) and pre-dialysis potassium was reduced from 4.96 ± 0.62 to 4.79 ± 0.49 mmol/l without dietary change. Pre-dialysis bicarbonate increased from 18.15 ± 1.35 to 20.27 ± 1.88 mmol/l, however with an increase in blood pressure. Nutritionally, lean tissue mass was reduced in the controls suggesting less catabolism in the intervention group. There was no change in ECGs. Limitations are small sample size and unblinded study design lacking a placebo, with several participants failing to achieve the target of 22 mmol/l serum bicarbonate levels due mainly to tablet burden. CONCLUSION: Oral sodium bicarbonate reduced bicarbonate loss and potassium gain in the inter-dialytic period, and may also preserve lean tissue mass. TRIAL REGISTRATION: The study was registered prospectively on 06/08/2015 with EU Clinical Trials Register EudraCT number 2015-001439-20 .

Global Prevalence of Protein-Energy Wasting in Kidney Disease: A Meta-analysis of Contemporary Observational Studies From the International Society of Renal Nutrition and Metabolism.

OBJECTIVE: To better define the prevalence of protein-energy wasting (PEW) in kidney disease is poorly defined. METHODS: We performed a meta-analysis of PEW prevalence from contemporary studies including more than 50 subjects with kidney disease, published during 2000-2014 and reporting on PEW prevalence by subjective global assessment or malnutrition-inflammation score. Data were reviewed throughout different strata: (1) acute kidney injury (AKI), (2) pediatric chronic kidney disease (CKD), (3) nondialyzed CKD 3-5, (4) maintenance dialysis, and (5) subjects undergoing kidney transplantation (Tx). Sample size, period of publication, reporting quality, methods, dialysis technique, country, geographical region, and gross national income were a priori considered factors influencing between-study variability. RESULTS: Two studies including 189 AKI patients reported a PEW prevalence of 60% and 82%. Five studies including 1776 patients with CKD stages 3-5 reported PEW prevalence ranging from 11% to 54%. Finally, 90 studies from 34 countries including 16,434 patients on maintenance dialysis were identified. The 25th-75th percentiles range in PEW prevalence among dialysis studies was 28-54%. Large variation in PEW prevalence across studies remained even when accounting for moderators. Mixed-effects meta-regression identified geographical region as the only significant moderator explaining 23% of the observed data heterogeneity. Finally, two studies including 1067 Tx patients reported a PEW prevalence of 28% and 52%, and no studies recruiting pediatric CKD patients were identified. CONCLUSION: By providing evidence-based ranges of PEW prevalence, we conclude that PEW is a common phenomenon across the spectrum of AKI and CKD. This, together with the well-documented impact of PEW on patient outcomes, justifies the need for increased medical attention.