OBJECTIVE: The present systematic review and meta-analysis aims to determine the difference in the interdialytic weight gain (IDWG) between low salt intake diet and normal/high salt intake diet or between nutritional counseling aimed at reducing diet salt intake and no nutritional counseling in patients on chronic hemodialysis.
METHODS: Medline, PubMed, Web of Science, and the Cochrane Library were searched. Randomized, crossover or parallel studies and observational studies were considered for inclusion and: 1) included adult patients on chronic hemodialysis since at least 6 months; 2) compared normal salt intake diet with low salt intake diet on IDWG; 3) compared nutritional counseling aimed at reducing diet salt intake with no intervention on IDWG; 4) reported on IDWG.
RESULTS: Eight articles (783 patients) were fully assessed for eligibility and included in the investigation. Meta-analysis showed frequencies of patients that increased their weight after dialysis more than 2.5 Kg (events) over total enrolled subjects for each group (control and experimental). As no significant heterogeneity was observed (I2 = 8%; p = 0.36), the pooled analysis was performed using a fixed-effect model. Funnel plot was generated and no obvious asymmetry was observed. The Overall Odds Ratio to get an event in the experimental group, in respect to controls, is 0.57 (0.33-0.97) (p = 0.04] with single studies OR ranging between 0.11 and 1.08.
CONCLUSIONS: The present systematic review and meta-analysis suggest that the use of a low salt diet sodium or a nutritional counseling aimed at reducing diet salt intake is associated with a statistically significant reduction of the IDWG in patients on chronic hemodialysis.

OBJECTIVE: Patient activation is a concept that refers to the willingness to manage one\'s health and medical care. To assess it, a patient activation measure (PAM) has been developed and validated. Several studies report low activation in patients with chronic diseases. However, information on activation in hemodialysis patients is scarce. The aim of the present study is to describe the activation level of patients on chronic treatment in an HD unit and its relationship with disease control parameters.
METHODS: Cross-sectional observational study in patients with advanced chronic kidney disease on chronic HD treatment. Ninety-six patients were included. Activation was measured with the PAM-13 questionnaire. Its relationship with descriptive variables (age, sex, comorbidity, studies, habitat) and disease control variables (vascular access, blood flow, potassaemia, phosphataemia, interdialytic gain) was studied. For this purpose, Spearman\'s correlation test, multiple linear regression model and logistic model were used as statistical methods.
RESULTS: The mean (SD) PAM-13 score was 63.19 (15.21). Activation was significantly associated with vascular access (P = 0.003), blood flow (P = 0.024), and interdialytic gain of patients (P = 0.008).
CONCLUSIONS: Activation in patients on chronic hemodialysis treatment is low. Higher activation is related having an arteriovenous fistula, higher blood flow and lower interdialytic gain. Future studies are needed to confirm and apply our results.

BACKGROUND: Several countries are experiencing challenges in maintaining standard haemodialysis services for people with kidney failure.
OBJECTIVE: This study aimed to investigate the health profile of people receiving haemodialysis and to identify factors associated with interdialytic weight gain.
METHODS: A cross-sectional study.
METHODS: A total of 166 adults with kidney failure and receiving haemodialysis for at least 3 months were included.
METHODS: A structured chart audit form collected, demographic and haemodialysis treatment characteristics, recent biochemical and haematological results, and prescribed treatment regimens from clinical records. Data were analysed descriptively. Odds ratios (OR) were calculated to identify independent risk factors for interdialytic weight gain.
RESULTS: Mean age was 52 years (SD = 12.5), over half were male (60.2%, n = 100), and most were receiving 4 h of haemodialysis once per week (87.3%, n = 145). Approximately half (51.8%, n = 86) had an interdialytic weight gain >2%. Being female (OR = 3.39; 95% CI, 1.51-7.61), increased comorbidities (OR = 1.50; 95% CI, 1.22-1.84) and having BMI outside of the normal range (overweight/obese [OR = 8.49; 95% CI, 3.58-20.13] or underweight [OR = 4.61; 95% CI, 1.39-15.31]) were independent risk factors for increased interdialytic weight gain.
CONCLUSIONS: Most patients were receiving 4 h of haemodialysis once per week although only modest alterations in potassium, phosphate, and fluid status were observed. Understanding the patient profile and predictors of interdialytic weight gain will inform the development of self-management interventions to optimise clinician support.

BACKGROUND: The aim of this study was to investigate changes in echocardiographic right ventricular (RV) indices in relation to the degree of fluid accumulation between hemodialysis sessions, evaluated according to the recommended threshold of interdialytic-weight-gain corrected for dry weight (IDWG%).
METHODS: A post-hoc analysis was performed using data from 41 maintenance hemodialysis patients. Patients were divided into a higher (>4.5%) and a lower (<4.5%) IDWG% group and underwent an echocardiographic assessment at the start and the end of the 3-day and the 2-day interdialytic interval.
RESULTS: RV systolic pressure (RVSP) increments were more pronounced in the higher compared to the lower IDWG% group (16.43 ± 5.37 vs. 14.11 ± 13.38 mm Hg respectively, p = 0.015) over the 3-day interval, while changes in RV filling pressures, did not differ significantly between the groups (p = 0.84).
CONCLUSIONS: During the 3-day interdialytic interval, pulmonary circulation is particularly overloaded in patients with fluid accumulation higher than the recommended thresholds, as evidenced by higher RVSP elevations.

OBJECTIVE: The present systematic review and meta-analysis aimed at evaluating the effect of low dialysate sodium concentration on interdialytic weight gain (IDWG) in chronic hemodialysis patients.
METHODS: Studies were eligible for inclusion if they were English language papers published in a peer-reviewed journal and met the following inclusion criteria: (1) studies in adult patients (over 18 years of age), (2) included patients on chronic hemodialysis since at least 6 months; (3) compared standard (138-140 mmol/l) or high (> 140 mmol/l) dialysate sodium concentration with low (< 138 mmol/l) dialysate sodium concentration; (4) Included one outcome of interest: interdialytic weight gain. Medline, PubMed, Web of Science, and the Cochrane Library were searched for the quality of reporting for each study was performed using the Quality Assessment Tool of Controlled Intervention Studies of the National Institutes of Health. The quality of reporting of each cross-over study was performed using the Revised Cochrane Risk of Bias (RoB) tool for cross-over trials as proposed by Ding et al. RESULTS: Nineteen studies (710 patients) were included in the analysis: 15 were cross-over and 4 parallel randomized controlled studies. In cross-over studies, pooled analysis revealed that dialysate sodium concentration reduced IDWG with a pooled MD of - 0.40 kg (95% CI - 0.50 to - 0.30; p < 0.001). The systematic review of four parallel, randomized, studies revealed that the use of a low dialysate sodium concentration was associated with a significant reduction of the IDWG in two studies, sustained and almost significant (p = 0.05) reduction in one study, and not significant reduction in one study.
CONCLUSIONS: Low dialysate sodium concentration reduces the IDWG in prevalent patients on chronic hemodialysis.

BACKGROUND: Some previous studies have reported an effect of increasing subjective thirst and interdialytic weight gains (IDWG), and that this may be influenced by nonadherence to dietary sodium restrictions, whereas others reported no such association. As such we wished to review the effect of self-reported thirst on IDWGs and dietary sodium intake.
METHODS: Dialysis patients were asked to complete visual analogues thirst, distress thermometer (DT) scores and complete a sodium food frequency questionnaire (SFFQ). IDWG and pre and post dialysis volumes were measured with multifrequency bioelectrical impedance.
RESULTS: One hundred and eleven patients completed the questionnaires and had bioimpedance measurements: 63% male, mean age 63.8 ± 16.1 years, 33% diabetic with a median thirst score 3 (0-5) and SFFQ 52.0 ± 18, and IDWG 2.1 ± 1.3%. Thirst was associated with DT (r = 0.28, p = 0.004) and negatively with age (r = -0.31, p < 0.001), but not SFFQ, IDWG, extracellular water, or dialysate sodium, or dialysate to plasma gradient. Patients with higher thirst scores were younger (58.0 ± 15.2 vs. 69.4 ± 15.0 years, p < 0.001) with higher DT scores (5 [2-7] vs. 2 [0-5], p < 0.001). On multivariate logistic analysis, only age was associated with self-reported thirst (odds ratio 0.95, 95% confidence limits 0.92-0.98, p < 0.001).
CONCLUSIONS: We found that subjective thirst was greater for younger patients and those who reported higher levels of distress, but no association with IDWGs, dietary sodium intake, or dialysate sodium. However, most of our patients followed the dietary advice, as evidenced by the low SFFQ scores and % IDWGs. Whether thirst increases distress or distress increases subjective thirst remains to be determined.

BACKGROUND: Although hemodialysis is lifesaving in patients with kidney failure extensive interdialytic weight gain (IDWG) between dialyses worsens the prognosis. We recently showed a strong correlation between IDWG and predialytic values of cardiac markers. The aim of the present study was to evaluate if the cardiac markers N-terminal pro-B-type natriuretic peptide (proBNP) and troponin T were influenced by IDWG and speed of fluid removal (ultrafiltration-rate).
METHODS: Twenty hemodialysis patients performed in total 60 hemodialysis (three each). Predialytic values of proBNP and troponin T and changes from predialysis to 180 min hemodialysis (180-0 min) were compared with the IDWG calculated in percent of body weight. The ultrafiltration-rate was adjusted (UF-rateadj ) to IDWG: (100 × weight gain between dialysis [kg])/(estimated body dry weight [kg] × length of hemodialysis session [hours]).
RESULTS: UF-rateadj correlated (Spearman) with (1) predialytic values of IDWG (r = 0.983, p < 0.001), proBNP (r = 0.443, p < 0.001), and troponin T (r = 0.296, p = 0.025); and (2) differences in proBNP180-0min (r = 0.572, p < 0.001) and troponin T180-0min (r = 0.400, p = 0.002). UF-ratesadj above a breakpoint of 0.60 caused more release of proBNP180-0min (p = 0.027). Remaining variables in multiple regression analysis with ProBNP180-0min as dependent factor were predialytic proBNP (p < 0.001) and the ultrafiltration-rate (p < 0.001).
CONCLUSIONS: Higher UF-rateadj during dialysis was correlated to increased levels of cardiac markers. Data support a UF-rateadj lower than 0.6 to limit such increase. Further studies may confirm if limited fluid intake and a lower UF-rateadj should be recommended to prevent cardiac injury during dialysis.

Adherence to a low-sodium (Na) diet is crucial in patients under hemodialysis, as it improves cardiovascular outcomes and reduces thirst and interdialytic weight gain. Recommended salt intake is lower than 5 g/day. The new 6008 CAREsystem monitors incorporate a Na module that offers the advantage of estimating patients\' salt intake. The objective of this study was to evaluate the effect of dietary Na restriction for 1 week, monitored with the Na biosensor.
A prospective study was conducted in 48 patients who maintained their usual dialysis parameters and were dialyzed with a 6008 CAREsystem monitor with activation of the Na module. Total Na balance, pre-/post-dialysis weight, serum Na (sNa), changes in pre- to post-dialysis sNa (ΔsNa), diffusive balance, and systolic and diastolic blood pressure were compared twice, once after 1 week of patients\' usual Na diet and again after another week with more restricted Na intake.
Restricted Na intake increased the percentage of patients on a low-Na diet (<85 Na mmol/day) from 8% to 44%. Average daily Na intake decreased from 149 ± 54 to 95 ± 49 mmol, and interdialytic weight gain was reduced by 460 ± 484 g per session. More restricted Na intake also decreased pre-dialysis sNa and increased both intradialytic diffusive balance and ΔsNa. In hypertensive patients, reducing daily Na by more than 3 g Na/day lowered their systolic blood pressure.
The new Na module allowed objective monitoring of Na intake, which in turn could permit more precise personalized dietary recommendations in patients under hemodialysis.

Interdialytic weight gain (IDWG) is crucial in the association between long interdialytic intervals and mortality in hemodialysis patients. The impact of IDWG on changes in residual kidney function (RKF) has not been evaluated thoroughly. This study examined the associations of IDWG in the long intervals (IDWGL) with mortality and rapid RKF decline.
This retrospective cohort study included patients who initiated hemodialysis in the United States dialysis centers from 2007 to 2011. IDWGL was defined as IDWG in the two-day break between dialysis sessions. This study examined the associations of seven categories of IDWGL (0% to <1%, 1% to <2%, 2% to <3% [reference], 3% to <4%, 4% to <5%, 5% to <6%, and ≥6%) with mortality using Cox regression models and rapid decline of renal urea clearance (KRU) using logistic regression models. The continuous relationships between IDWGL and study outcomes were investigated using restricted cubic spline analyses.
Mortality and rapid RKF decline were assessed in 35,225 and 6425 patients, respectively. Higher IDWGL categories were linked to increased risk of adverse outcomes. The multivariate adjusted hazard ratios (95% confidence intervals) of all-cause mortality for 3% to <4%, 4% to <5%, 5% to <6%, and ≥6% IDWGL were 1.09 (1.02-1.16), 1.14 (1.06-1.22), 1.16 (1.06-1.28), and 1.25 (1.13-1.37), respectively. The multivariate adjusted odds ratios (95% confidence intervals) of rapid decline of KRU for 3% to <4%, 4% to <5%, 5% to <6%, and ≥6% IDWGL were 1.03 (0.90-1.19), 1.29 (1.08-1.55), 1.17 (0.92-1.49), and 1.48 (1.13-1.95), respectively. When IDWGL exceeded 2%, the hazard ratios of mortality and the odds ratios of rapid KRU decline continuously increased.
Higher IDWGL was incrementally associated with higher mortality risk and rapid KRU decline. IDWGL level over 2% was linked to higher risk of adverse outcomes. Therefore, IDWGL may be utilized as a risk parameter for mortality and RKF decline.

Sodium (Na) balance is unexplored in dialyzed children. We assessed a simplified sodium balance (sNaB) and its correlates in pediatric patients receiving maintenance dialysis.
Patients < 18 years old on hemodialysis (HD) or peritoneal dialysis (PD) in six European Pediatric Dialysis Working Group centers were recruited. sNaB was calculated from enteral Na, obtained by a 3-day diet diary, Na intake from medications, and 24-h urinary Na (uNa). Primary outcomes were systolic blood pressure and diastolic blood pressure standard deviation scores (SBP and DBP SDS), obtained by 24-h ambulatory blood pressure monitoring or office BP according to age, and interdialytic weight gain (IDWG).
Forty-one patients (31 HD), with a median age of 13.3 (IQR 5.2) years, were enrolled. Twelve patients (29.3%) received Na-containing drugs, accounting for 0.6 (0.7) mEq/kg/day. Median total Na intake was 1.5 (1.1) mEq/kg/day, corresponding to 60.6% of the maximum recommended daily intake for healthy children. Median uNa and sNaB were 0.6 (1.8) mEq/kg/day and 0.9 (1.7) mEq/kg/day, respectively. The strongest independent predictor of sNaB in the cohort was urine output. In patients receiving HD, sNaB correlated with IDWG, pre-HD DBP, and first-hour refill index, a volume index based on blood volume monitoring. sNaB was the strongest predictor of IDWG in multiple regression analysis (β = 0.63; p = 0.005). Neither SBP SDS nor DBP SDS correlated with sNaB.
Na intake is higher than uNa in children on dialysis, and medications may be an important source of Na. sNaB is best predicted by urine output in the population, and it is a significant independent predictor of IDWG in children on HD. A higher resolution version of the Graphical abstract is available as Supplementary information.