Is a body mass index of 23 kg/m2 a reliable marker of protein–energy wasting in hemodialysis patients?

Estimating the association between systemic Interleukin-6 and mortality in the dialysis population. Re-analysis of the global fluid study, systematic review and meta-analysis

BACKGROUND

Systemic inflammation, measured as circulating Interleukin-6 (IL-6) levels, is associated with cardiovascular and all-cause mortality in chronic kidney disease. However, this has not been convincingly demonstrated in a systematic review or a meta-analysis in the dialysis population. We provide such evidence, including a re-analysis of the GLOBAL Fluid Study.

METHODS

Mortality in the GLOBAL fluid study was re-analysed using Cox proportional hazards regression with IL-6 levels as a covariate using a continuous non-logarithmic scale. Literature searches of the association of IL-6 levels with mortality were conducted on MEDLINE, EMBASE, PyschINFO and CENTRAL. All studies were assessed for risk of bias using the QUIPS tool. To calculate a pooled effect size, studies were grouped by use of IL-6 scale and included in the meta-analysis if IL-6 was analysed as a continuous linear covariate, either per unit or per 10 pg/ml, in both unadjusted or adjusted for other patient characteristics (e.g. age, comorbidity) models. Funnel plot was used to identify potential publication bias.

RESULTS

Of 1886 citations identified from the electronic search, 60 were included in the qualitative analyses, and 12 had sufficient information to proceed to meta-analysis after full paper screening. Random effects meta-analysis of 11 articles yielded a pooled hazard ratio (HR) per pg/ml of 1.03, (95% CI 1.01, 1.03), [Formula: see text]= 81%. When the analysis was confined to seven articles reporting a non-adjusted HR the result was similar: 1.03, per pg/ml (95% CI: 1.03, 1.06), [Formula: see text]=92%. Most of the heterogeneity could be attributed to three of the included studies. Publication bias could not be determined due to the limited number of studies.

CONCLUSION

This systematic review confirms the adverse association between systemic IL-6 levels and survival in people treated with dialysis. The heterogeneity that we observed may reflect differences in study case mix.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO - CRD42020214198.

Malnutrition score and Body Mass Index as nutritional screening tools for hemodialysis patients

BACKGROUND AND AIMS

Malnutrition is highly prevalent in the hemodialysis population. Nutritional screening is important to identify patients at risk of malnutrition. This study aimed to investigate the concurrent validity of BMI cut-offs (BMI < 23 kg/m² and BMI < 18.5 kg/m²) and DMS, as simple nutritional screening tools, compared to PG-SGA, as the reference standard, in detecting the risk of malnutrition in hemodialysis patients.

DESIGN

A Single-centered cross-sectional study design.

METHODS

A total of 98 patients on maintenance hemodialysis, who were at least 18 years old (mean age: 51.33 ± 14.12) and subjected to hemodialysis for at least 3 months, were screened. Concurrent validity was assessed using receiver operating characteristic (ROC) curve analysis as well as sensitivity, specificity, accuracy, PPV, NPV, LR⁺ and LR^-, against diagnosed malnutrition.

RESULTS

The patients considered malnourished were 71.4% (n = 70), with the majority being females (60%), and possessed a BMI distribution of 28.2 ± 6.3 kg/m². DMS (score ≥ 14) agreed with diagnosed malnutrition (κ = 0.450 (95% CI 0.26-0.64) <0.0005). Furthermore, DMS (score ≥ 14) showed a sensitivity and a specificity of 84.3% and 60.7%, respectively. However, BMI cut-offs (<23 kg/m² or < 18.5 kg/m²) did not show any agreement with diagnosed malnutrition.

CONCLUSION

DMS is a useful screening tool for detecting the risk of malnutrition in hemodialysis patients. On the contrary, BMI <23 kg/m² and BMI <18.5 kg/m² were not valid tools for identifying the risk of malnutrition in hemodialysis patients.

The Association between Nutritional Markers and Heart Rate Variability Indices in Patients Undergoing Chronic Hemodialysis

The associations between nutritional markers and heart rate variability (HRV) are poorly addressed. This study aimed to evaluate whether malnutrition is associated with the altered autonomic nervous system (ANS) function. This cross-sectional study was conducted enrolling 175 patients (100 women, mean age 65.1 ± 12.9 years) receiving chronic hemodialysis in a teaching hospital from June to August 2010. We performed HRV measurements before and during the index hemodialysis and compared these HRV values between two groups categorized by the individual nutritional marker. By using the multivariate generalized estimating equation with adjustment, we exhibited the independent associations between HRV and poor nutritional status defined by serum albumin < 3.8 g/dL, total cholesterol < 100 mg/dL, body mass index < 23 kg/m², bodyweight loss within six months > 10%, bodyweight loss within three months > 5%, and normalized protein catabolic rate < 1.1 g/kg BW/day. The current study disclosed ANS impairment in hemodialysis patients with poor nutritional status. The impaired ANS function might be a potential mechanism linking malnutrition to subsequent adverse prognoses in hemodialysis patients. Further investigations are warranted to confirm these findings and clarify the causal association among this complex issue.

Clinical Value of Muscle Mass Assessment in Clinical Conditions Associated with Malnutrition

Malnutrition results from a reduction of food intake or an alteration of nutrient assimilation and leads to decreased lean mass. Strong evidence shows that malnutrition associated with loss of muscle mass negatively impacts clinical outcomes. The preservation or improvement of muscle mass represents a challenge. This review aims to (1) describe current methods to assess muscle mass in clinical practice, (2) describe the associations between muscle mass and clinical outcomes, and (3) describe the impact of interventions aiming at increasing muscle mass on clinical outcomes. It highlights the importance of assessing muscle mass as part of the screening and the follow-up of malnutrition in clinical practice.

Diagnostic Usefulness of the Protein Energy Wasting Score in Prevalent Hemodialysis Patients

OBJECTIVE

To study whether the score proposed by the International Society of Renal Nutrition and Metabolism to define the protein energy wasting (PEW) syndrome has diagnostic validity in patients undergoing dialysis.

DESIGN AND METHODS

Cross-sectional study including 468 prevalent hemodialysis patients from Canary Islands, Spain. Individual PEW syndrome criteria and the number of PEW syndrome categories were related to other objective markers of PEW using linear and logistic regression analyses: subjective global assessment, handgrip strength, bioimpedance-assessed body composition, and levels of high-sensitivity C-reactive protein.

RESULTS

Study participants (34% women) had a median age of 66 years, 37 months of maintenance dialysis, and 50% were diabetics. About 23% of patients had PEW (≥3 PEW categories), and 68% were at risk of PEW (1-2 PEW categories). Low prealbumin was the most frequently found derangement (52% of cases), followed by low albumin (46%), and low protein intake (35%). Across higher number of PEW syndrome categories, patients showed a longer dialysis vintage and had lower creatinine, triglycerides, and transferrin (P for trend <.001 for all). All nutritional assessments not included in the PEW definition worsened across higher number of PEW categories. In multivariable regression analyses, there was a linear inverse relationship between muscle and fat mass as well as handgrip strength with the number of PEW syndrome categories. Likewise, the proportion of subjective global assessment-defined malnutrition and serum concentration of C-reactive protein gradually increased despite adjustment for confounders (P for trend <.05 for all).

CONCLUSION

The PEW score reflects systemic inflammation, malnutrition and wasting among dialysis patients and may thus be used for diagnostic purposes.

Diagnosis and prevalence of protein-energy wasting and its association with mortality in Japanese haemodialysis patients

AIM

The International Society of Renal Nutrition and Metabolism (ISRNM) has proposed the diagnostic criteria for protein-energy wasting (PEW). We studied Japanese haemodialysis (HD) patients to verify the diagnostic method, especially with respect to the body mass index (BMI) criterion, as well as the prevalence of PEW and its association with mortality.

METHODS

Japanese patients receiving maintenance HD at three outpatient clinics in Tokyo (n = 210) were enrolled, and prospectively followed-up for 3 years. PEW was diagnosed at baseline, according to the four categories (serum chemistry, body mass, muscle mass and dietary intake) recommended by the ISRNM. For the category of body mass, we select a body mass index (BMI) and set up three thresholds, <18.5, <20.0 and <23.0 kg/m² , as the diagnostic criterion. The patients who satisfied at least three out of the four categories were diagnosed as PEW.

RESULTS

Protein-energy wasting, when the threshold of a BMI among the diagnostic criteria was defined as <18.5 kg/m² , was recognized as an independent risk factor for mortality. However, PEW was not recognized as a risk factor when the BMI diagnostic criterion was set at <20.0 or <23.0 kg/m² . Overall, 14.8% of the patients had PEW. The survival rate of PEW patients was significantly lower than that of non-PEW patients (log rank, P < 0.001).

CONCLUSIONS

The diagnosis algorithm of PEW proposed by an expert panel of the ISRNM strongly associates with mortality. However, given differences in body size in Japan, we suggest to revise the BMI criterion from <23.0 kg/m² to <18.5 kg/m² .

Bioimpedance Spectroscopy as a Practical Tool for the Early Detection and Prevention of Protein-Energy Wasting in Hemodialysis Patients

OBJECTIVES

To evaluate whether body composition monitor (BCM) could be a practical instrument for nephrologists to assess nutritional status in patients on hemodialysis (HD) and whether it is more effective in identifying patients at highest risk of developing protein-energy wasting (PEW) alone or in combination with other tools currently used for that purpose.

DESIGN

Observational cross-sectional study in 91 HD patients (60 ± 14 years, 70.3% male, 24 ± 4.1 kg/m² body mass index) from 2 different locations.

METHODS

Nutritional status was evaluated by anthropometric methods (biceps and triceps skinfold thickness, waist circumference, and arm muscular circumference), biochemical nutritional markers, malnutrition-inflammation score (MIS), and BCM. The patients were grouped into those with and without PEW by using classical criteria and then classified as being adequately or inadequately nourished according to a BCM flow chart to detect those requiring preferential nutritional intervention. A multivariate approach was used to calculate the risk of developing PEW.

RESULTS

Anthropometric measurements revealed significantly lower body mass index (<23 kg/m²; odds ratios [OR] = 13.3 and P = 0.001) and arm muscular circumference < p10 (OR = 34, P < 0.001) in the PEW group. MIS was above 5 in all the patients classified as having PEW. BCM showed that fat tissue index < p10 was significantly lower in this group (OR = 1.52), and a decision tree using the lean tissue index < p10, fat tissue index < p10, and extracellular water > 15% revealed that 42.9% of the patients would need nutritional monitoring. On multivariate analysis, insufficient nutritional status detected by BCM decision tree was an independent prognostic factor for developing PEW. About 9.89% of the patients were classified as PEW, with MIS > 5, and insufficient nutritional status detected by BCM required preferential nutritional intervention.

CONCLUSION

BCM is a practical instrument for nephrologists to assess nutritional status in patients on HD and is useful for the early prevention and detection of PEW, as is able to identify differences in body composition, predict clinically important outcomes, and classify patients requiring preferential nutritional intervention.

Effect of Personalized Nutritional Counseling on the Nutritional Status of Hemodialysis Patients

This study set out to evaluate the impact of personalized nutritional counseling (PNC) on the nutritional status of hemodialysis (HD) patients. This was an intervention study for 10 months at 2 hospitals. Anthropometric, biochemical, dietary, and body composition parameters were measured at baseline and after 3 and 6 months of PNC. A total of 42 patients (23 men and 19 women) were included. Intake of dietary protein, serum albumin, and cholesterol levels had increased significantly from baseline to month 6 (p < 0.05). Among the bioelectrical impedance analysis (BIA) parameters, both the body cell mass (BCM) and the fat free mass (FFM) had significantly reduced at month 3 compared to baseline (p < 0.05). However, there was no difference between baseline and month 6. We assessed the nutritional status of the subjects using the malnutrition inflammation score (MIS), and divided them into an adequately nourished (AN) and a malnourished (MN) group at baseline. In the subgroup analysis, serum levels of albumin and cholesterol had increased significantly, particularly from baseline to month 6 in the MN group (p < 0.05). This study suggests that consecutive PNC contributed to the improvement of the protein intake, serum levels of albumin, cholesterol and to the delay of muscle wasting, which could also have a positive impact on the nutritional status, particularly in malnourished patients receiving HD treatment.

Retarding Chronic Kidney Disease (CKD) Progression: A Practical Nutritional Approach for Non-Dialysis CKD

This is a case report on a patient with non-dialysis chronic kidney disease (CKD) in whom several nutritional issues are briefly discussed from a practical point of view. The article is accompanied by an editorial published in this Journal in relation to the 2nd International Conference of the European Renal Nutrition working group at ERA-EDTA—“Retarding CKD progression: readily available through comprehensive nutritional management?”— and focuses on several practical topics associated with the nutritional approach for the conservative treatment of non-dialysis CKD. The article is divided into 3 sections—basic nutritional assessment, nutritional targets, and nutritional follow-up in non-dialysis CKD—linked to 3 consecutive steps of the clinical follow-up of the patient and the related nutritional concerns and intervention.

First visit: Baseline nutritional assessment and basic nutritional considerations in non-dialysis chronic kidney disease (CKD) • What nutritional assessment/monitoring for protein-energy wasting (PEW) should be employed? • Is a body mass index (BMI) of 21 kg/m2 adequate? • What phosphate target should be pursued? • What are the nutritional habits in patients with incident CKD? • What protein needs and amount of dietary protein should be pursued? • Does the quality of protein matter? • What amount of dietary salt should be employed? How should this be obtained? • How should normal serum phosphate be achieved? • What diet should be recommended? Is a vegetarian diet an option?

Second visit: Major nutritional targets in non-dialysis CKD • Consequences of unintentional weight loss • What is the role of the renal dietitian in helping the patient adhere to a renal diet?

Intermediate visits: Nutritional follow-up in non-dialysis CKD • What treatment for calcium/parathyroid hormone (PTH) will affect CKD progression? Final visits: • Would a dietary recall/intensive dietary education improve adherence with the diet? • Would a very-low-protein diet (VLPD)/ketodiet be indicated for this patient?

Impact of BMI Variations on Survival in Elderly Hemodialysis Patients

OBJECTIVES

In elderly hemodialysis patients, protein-energy wasting is associated with poor outcome; however, the association between body mass index (BMI) changes over time, and survival has been seldom studied in this particularly frail population.

DESIGN AND METHODS

This prospective study recruited 502 hemodialysis patients aged ≥75 years from the French cohort ARNOS and followed them from 2005 to 2009. BMI changes over time were modeled by individual linear regression models. Survival analyses used frailty Cox models.

RESULTS

The population average age was 80.9 years. Forty-one percent of the patients died during follow-up. A 1 kg/m(2) lower baseline BMI was associated with a 4% increase in the risk of death over the study period (hazard ratio [HR] 1.04, 95% confidence interval [1.01-1.08], P = .02). A 5% BMI loss per year was associated with a 52% increase in the risk of death (HR 1.52, 95% confidence interval [1.32-1.75], P < .001). In patients who lost weight (>5% BMI loss per year), the lower was the baseline BMI, the higher was the HR for death. There was a similar trend in the patients with stable weight (5% BMI loss-5% BMI gain per year). In patients who gained weight, the HR was unexpectedly higher than in those with stable weight.

CONCLUSIONS

In elderly hemodialysis patients, the impact of the BMI percent change on survival was stronger than that of the baseline BMI. Patients with stable weight had longer survivals than patients who lost or gained weight. Thus, in this population, BMI changes should be regularly assessed. Further studies should assess the safety of weight gain strategies.

Body composition and all-cause mortality in subjects older than 65 y

BACKGROUND

A low or high body mass index (BMI) has been associated with increased mortality risk in older subjects without taking fat mass index (FMI) and fat-free mass index (FFMI) into account. This information is essential because FMI is modulated through different healthcare strategies than is FFMI.

OBJECTIVE

We aimed to determine the relation between body composition and mortality in older subjects.

DESIGN

We included all adults ≥65 y old who were living in Switzerland and had a body-composition measurement by bioelectrical impedance analysis at the Geneva University Hospitals between 1990 and 2011. FMI and FFMI were divided into sex-specific quartiles. Quartile 1 (i.e., the reference category) corresponded to the lowest FMI or FFMI quartile. Mortality data were retrieved from the hospital database, the Geneva death register, and the Swiss National Cohort until December 2012. Comorbidities were assessed by using the Cumulative Illness Rating Scale.

RESULTS

Of 3181 subjects included, 766 women and 1007 men died at a mean age of 82.8 and 78.5 y, respectively. Sex-specific Cox regression models, which were used to adjust for age, BMI, smoking, ambulatory or hospitalized state, and calendar time, showed that body composition did not predict mortality in women irrespective of whether comorbidities were taken into account. In men, risk of mortality was lower with FFMI in quartiles 3 and 4 [HR: 0.78 (95% CI: 0.62, 0.98) and 0.64 (95% CI: 0.49, 0.85), respectively] but was not affected by FMI. When comorbidities were adjusted for, FFMI in quartile 4 (>19.5 kg/m(2)) still predicted a lower risk of mortality (HR: 0.72; 95% CI: 0.54, 0.96).

CONCLUSIONS

Low FFMI is a stronger predictor of mortality than is BMI in older men but not older women. FMI had no impact on mortality. These results suggest potential benefits of preventive interventions with the aim of maintaining muscle mass in older men. This trial was registered at clinicaltrials.gov as NCT01472679.

NOURISH, Nutritional OUtcomes from a Randomised Investigation of Intradialytic oral nutritional Supplements in patients receiving Haemodialysis: a pilot randomised controlled trial

Background

The study was done to assess the feasibility of conducting a trial evaluating the use of an intradialytic oral nutritional supplement (ONS) on nutritional status.

Methods

The study design is a single centre, parallel group, external pilot randomised controlled trial (RCT). The setting was at a haemodialysis unit in Sheffield, UK. The aim was to recruit 30 trial participants to allow at least 12 evaluable patients per arm, but the actual study sample consisted of 10 adults with a body mass index (BMI) ≤22 kg/m², receiving thrice weekly haemodialysis. All participants received nutritional advice from a renal dietitian as per usual practice. The intervention included the provision of an intradialytic ONS. Feasibility outcomes included recruitment to time and retention of participants along with palatability of ONS. Secondary outcomes were clinical parameters to obtain variance and estimates of effect size to inform the sample size calculation for a definitive trial.

Results

Recruitment was undertaken for a fixed period of 6 weeks. Rates were lower than expected mainly due to ineligibility with only 7% of screened patients (19/265) being eligible and 4% (10/265) of these being recruited. Due to the small proportion of patients eligible for the trial, all haemodialysis patients at the specified unit were assessed for eligibility. Data completion rates were low for session questionnaires (23%). Sample sizes derived from variance in secondary outcome measure of handgrip strength and adjusted for a dropout rate of 20% indicate that 189 patients would be required for a definitive RCT, requiring 19 UK haemodialysis units to participate.

Conclusions

A definitive RCT is feasible with some adaptation to exclusion criteria and methodology. The exclusion criteria could be adapted to include an increase in upper limit for BMI. The use of questionnaires at each dialysis session may not be feasible but the inclusion of appetite and supplement consumption data collection at the main assessments would provide similar outcome data. Quality of life assessment using SF-12 would be acceptable.

Trial registration

ISRCTN37431579.

Intensive weight loss combining flexible dialysis with a personalized, ad libitum, coach-assisted diet program. A "pilot" case series

Obesity is a growing problem on dialysis. The best approach to weight loss has not been established. The risks of malnutrition may offset the advantages of weight loss. Personalized hemodialysis schedules, with an incremental approach, are gaining interest; to date, no studies have explored its potential in allowing weight loss. This case series reports on combining flexible, incremental hemodialysis, and intensive weight loss.

SETTING

a small Dialysis Unit, following incremental personalized schedules (2-6 sessions/week, depending on residual function), tailored to an equivalent renal clearance >12 mL/min. Four obese and two overweigh patients (5 male, 1 female; age: 40-63 years; body mass index [BMI] 31.1 kg/m(2)) were enrolled in a coach-assisted weight loss program, with an "ad libitum" approach (3-6 foods/day chosen on the basis of their glycemic index and glycemic load). The diet consists of 8 weeks of rapid weight loss followed by 8-12 weeks of maintenance; both phases can be repeated. This study measures weight loss, side effects, and patients' opinions. Over 12-30 months, all patients lost weight (median -10.3 kg [5.7-20], median ΔBMI-3.2). Serum albumin (pre-diet 3.78; post-diet 3.83 g/dL), hemoglobin (pre-diet 11; post-diet 11.2 g/dL), and acid-base balance (HCO(3) pre-diet: 23.3; post-diet: 23.4 mmol/L) remained stable, with decreasing needs for erythropoietin and citrate or bicarbonate supplements. Calcium-phosphate-parathyroid hormone (PTH) balance improved (PTH-pre 576; post 286 pg/mL). Three out of 4 hypertensive patients discontinued, 1 decreased antihypertensives. None experienced severe side effects. Patient satisfaction was high (9 on a 0-10 analog scale). Personalized, incremental hemodialysis schedules allow patient enrollment in intensive personalized weight loss programs, with promising results.