Initial body mass indexes have contrary effects on change in body weight and mortality of patients on maintenance hemodialysis treatment

Effects of oral nutritional supplements on the nutritional status and inflammatory markers in patients on maintenance dialysis: a systematic review and meta-analysis of randomized clinical trials

Background and aims

Patients on hemodialysis (HD) or peritoneal dialysis (PD) often have insufficient energy and protein intake, resulting in poor nutritional status and adverse outcomes. Oral nutritional supplements (ONSs) are the most commonly used to increase such patients' energy and protein intakes.

Methods

In this systematic review and meta-analysis, we analyzed studies on nutritional status, inflammatory markers, and electrolyte levels in patients on dialysis receiving ONSs. We searched four electronic databases from inception until 31 December 2022, for randomized controlled trials comparing ONS treatment versus placebo or routine care.

Results

22 studies with 1185 patients on dialysis were included in our meta-analysis. Compared with the control group, the ONS group exhibited significantly increased serum albumin levels [1.26 g/l (95%CI, 0.50-2.02, P < 0.0001; I2 = 80.4%)], body mass indexes (BMIs) [0.30 kg/m2 (95%CI, 0.09-0.52, P = 0.005; I2 = 41.4%)], and handgrip strength (HGS) [0.96 kg (95%CI, 0.07-1.84, P = 0.034; I2 = 41.4%)] from baseline to the end of intervention. No significant differences were observed between the groups in lean body mass, phase angle, C-reactive protein, and serum phosphorus and potassium levels. In terms of improving albumin, the subgroup analyses show that ONS use seems to be more inclined to three variations: HD patients, short-term use, and non-intradialytic supplementation.

Conclusion

In conclusion, ONS use can improve the nutritional status of patients on dialysis in terms of their serum albumin, BMI, and HGS without significant effects on serum phosphorus, potassium, and C-reactive protein levels. However, it remains uncertain whether these results translate to improvement in clinically relevant outcomes. Large-scale high-quality studies are still required in this population.

What is the Optimal Fat Mass in Peritoneal Dialysis Patients?

The prevalence of obesity in peritoneal dialysis (PD) populations has risen dramatically since the mid-1980s. This epidemic has been driven by the increased prevalence of obesity in the general population, the increased risk of progression of chronic kidney disease to end-stage renal failure (ESRF) in obese subjects, the reduced probability of listing obese dialysis patients for renal transplantation, a paradoxical enhanced survival in at least some obese populations on dialysis as compared with non-obese ESRF patients, and a possible adipogenic effect of excessive peritoneal glucose absorption in PD. Although obesity has consistently been associated with improved outcomes in hemodialysis, conflicting results have been seen in PD. In general, an elevated body mass index (BMI) has been associated with a neutral or deleterious impact on PD outcomes, and the relationship appears to be explained predominantly by fat mass. Risk is also elevated in patients with a low BMI, such that the “optimal BMI” appears to lie between 20 kg/m2 and 25 kg/m2. The mechanisms underpinning the harmful effect of obesity appear to include increased peritonitis rate, proinflammatory effects, and a more rapid decline of residual renal function in obese patients. No proof exists that weight reduction engenders an improvement in outcome in PD patients, but the available studies suggest that cautious weight reduction is advisable. A few studies have demonstrated that clinically important and sustained weight reduction can be successfully achieved through a combination of individual meal plans, regular exercise, and substitution of icodextrin for dextrose in the once-daily long dwell.

Body Mass Index and All-cause Mortality in Chronic Kidney Disease: A Dose-response Meta-analysis of Observational Studies

This article provides a dose-response meta-analysis to evaluate the relationship between body mass index (BMI) and all-cause and disease-specific mortality in chronic kidney disease (CKD) by pooling together early stage, hemodialysis, and peritoneal dialysis patients. We evaluated eligible studies that published between 1966 and December 2014 by searching in PubMed, Object View and Interaction Design (OVID), and the Scopus databases. We used random-effects generalized least squares spline models for trend estimation to derive pooled dose-response estimates. Nonlinear associations of BMI with all-cause mortality were observed (P-nonlinearity < .0001), with an increased rate of mortality with BMIs > 30 kg/m² in all stages of CKD together. However, reanalysis of data separately by stage of CKD (hemodialysis and peritoneal dialysis) showed that the risk of all-cause mortality decreased with a steep slope in individuals with BMIs > 30 kg/m². This meta-analysis indicates that higher BMI has protective effects with respect to all-cause mortality in patients with both type of dialysis.

Obesity and the risk of cardiovascular and all-cause mortality in chronic kidney disease: a systematic review and meta-analysis

Background

Obesity is a risk factor for cardiovascular disease and death in people without chronic kidney disease (CKD), but the effect of obesity in people with CKD is uncertain.

Methods

Medline and Embase (from inception to January 2015) were searched for cohort studies measuring obesity by body mass index (BMI), waist:hip ratio (WHR) and/or waist circumference (WC) and all-cause and cardiovascular mortality or events in patients with any stage of CKD. Data were summarized using random effects models. Meta-regression was conducted to assess sources of heterogeneity.

Results

Of 4065 potentially eligible citations, 165 studies ( n = 1 534 845 participants) were analyzed. In studies that found a nonlinear relationship, underweight people with CKD (3-5) on hemodialysis experienced an increased risk of death compared with those with normal weight. In transplant recipients, excess risk was observed at levels of morbid obesity (>35 kg/m 2 ). Of studies that found the relationship to be linear, a 1 kg/m 2 increase in BMI was associated with a 3 and 4% reduction in all-cause and cardiovascular mortality in patients on hemodialysis, respectively {adjusted hazard ratio [HR] 0.97 [95% confidence interval (CI) 0.96-0.98] and adjusted HR 0.96 (95% CI 0.92-1.00)}. In CKD Stages 3-5, for every 1 kg/m 2 increase in BMI there was a 1% reduction in all-cause mortality [HR 0.99 (95% CI 0.0.97-1.00)]. There was no apparent association between obesity and mortality in transplanted patients or those on peritoneal dialysis. Sparse data for WHR and WC did not allow further analyses.

Conclusions

Being obese may be protective for all-cause mortality in the predialysis and hemodialysis populations, while being underweight suggests increased risk, but not in transplant recipients.

Eicosapentaenoic Acid as a Potential Therapeutic Approach to Reduce Cardiovascular Risk in Patients with End-Stage Renal Disease on Hemodialysis: A Review

Background

Patients with end-stage renal disease on hemodialysis have excess cardiovascular disease (CVD) burden with substantially increased CV event rates compared with the general population.

Summary

Traditional interventions that, according to standard clinical guidelines, reduce CV risk such as antihypertensive therapy, diet, exercise, and statins are not similarly effective in the hemodialysis population. This raises the question of whether additional risk factors, such as enhanced inflammation and oxidative stress, may drive the increased CVD burden in hemodialysis patients. Eicosapentaenoic acid (EPA), an omega-3 polyunsaturated fatty acid, is incorporated into the atherosclerotic plaque as well as membrane phospholipid bilayers and produces beneficial effects on inflammatory and oxidative mechanisms involved in atherosclerotic plaque formation and progression. EPA levels and the ratio of EPA to the omega-6 polyunsaturated fatty acid arachidonic acid (AA) are reduced in hemodialysis patients. Serum EPA levels have been inversely correlated with proinflammatory cytokines, and the EPA/AA ratio has been inversely associated with CV events in hemodialysis cohorts. Three recent studies involving over 800 hemodialysis patients and follow-up of 2-3 years suggest that EPA therapy may improve clinical outcomes in this patient population as evidenced by significant reductions in cardiovascular mortality, all-cause mortality, and/or CV events.

Key Messages

Further studies with high-purity EPA are warranted in patients on hemodialysis, especially given the fact that other interventions including antihypertensives, diet, exercise, and statins have not provided meaningful benefit.

Effect of body mass index and albumin on mortality rates for adult African-American hemodialysis patients

PURPOSE

The purpose of this retrospective descriptive study was to investigate if body mass index (BMI) and serum albumin (SA) impacted mortality rates in adult African-American patients on hemodialysis (HD).

DATA SOURCES

Records of 204 patients on HD (N = 204) from a clinic in the metropolitan Detroit area were examined for the period January 1, 2007-December 31, 2012 to determine the relationship of BMI and SA on mortality rates in this population. Logistics regression was utilized to analyze the association of several risk factors (BMI and SA) on survival (mortality rates).

CONCLUSION

Research findings from this study demonstrated that both undernourishment (being underweight; BMI < 23 kg/m(2) ) and hypoalbuminemia (<3.2g/dL) were strong predictors of death in patients on HD. However, obesity provided a survival advantage for adult African-American patients on HD (p = .030). Patients with higher SA levels also survived longer (p < .001).

IMPLICATIONS FOR PRACTICE

Advanced practice nurses (APNs) working with adult African-American patients on HD could work on developing targeted nutritional interventions to maintain higher SAs and BMIs while awaiting the results of further research in this area.

Body mass index and mortality in patients on maintenance hemodialysis: a meta-analysis

PURPOSE

In patients undergoing maintenance hemodialysis (MHD), increasing numbers of studies have reported a reduced mortality in patients with an increased body mass index (BMI). This article provides a meta-analysis on the assessment of the relationship between BMI and mortality in MHD patients.

METHODS

A systemic literature review was conducted to identify studies that examined all-cause mortality, with or without cardiovascular events, on the basis of bodyweight or obesity measures in MHD population published before October 2012.

RESULTS

Eight observational studies with a total of 190,163 patients were included. Compared to the individuals with a normal BMI, overweight patients and obese patients were associated with lower all-cause mortality [relative risk (RR) 0.86, 95% confidence interval (CI) 0.84-0.88; RR 0.77, 95% CI 0.75-0.78, respectively] and cardiovascular mortality (RR 0.86; 95% CI 0.81-0.91; RR 0.78, 95% CI 0.73-0.83, respectively). Underweight patients had relatively higher all-cause and cardiovascular mortality (RR 1.22, 95% CI 1.20-1.25; RR 1.19, 95% CI 1.11-1.28, respectively). In an obesity-stratified analysis, the patients with moderate or severe obesity presented a strongly decreased all-cause mortality risk (RR 0.64, 95% CI 0.61-0.68) and cardiovascular mortality risk (RR 0.63, 95% CI 0.53-0.75) compared to patients with mild obesity (RR 0.74, 95% CI 0.71-0.77; RR 0.81, 95% CI 0.75-0.87, respectively).

CONCLUSIONS

These findings show that overweight and obese patients have lower all-cause and cardiovascular mortality rates in patients undergoing MHD. Body weight management and optimized nutritional and metabolic support should help to reduce the high mortality rates that are prevalent in the hemodialysis population.

The impact of wait list body mass index changes on the outcome after liver transplantation

Obesity is associated with poor health outcomes in the general population, but the evidence surrounding the effect of body mass index (BMI) on postliver transplantation survival is contradictory. The aim of this study was to assess the impact of wait list BMI and BMI changes on the outcomes after liver transplantation. Using the Scientific Registry of Transplant Recipients, we compared survival among different BMI categories and examined the impact of wait list BMI changes on post-transplantation mortality for patients undergoing liver transplantation. Cox proportional hazards multivariate regression was carried out to adjust for confounding factors. Among 38 194 recipients, underweight patients had a poorer survival compared with normal weight (HR = 1.3, 95% CI: 1.13-1.49). Conversely, overweight and mildly obese men experienced better survival rates compared with their lean counterparts (HR = 0.9, 95% CI: 0.84-0.96, and HR = 0.86, 95% CI: 0.79-0.93 respectively). Female patients gaining weight over 18.5 kg/m(2) while on the wait list showed improving outcomes (HR = 0.46, (95% CI: 0.28-0.76)) compared with those remaining underweight. This study supports the harmful impact of underweight on postliver transplant survival, and highlights the need for a specific monitoring and management of candidates with BMIs close to 18.5 kg/m(2) . Obesity does not constitute an absolute contraindication to liver transplantation.

Comparison of azithromycin and clarithromycin triple therapy regimens for helicobacter pylori eradication in hemodialysis patients

Background

Helicobacter pylori eradication with clarithromycin is more expensive than with azithromycin.

Objectives

This study aimed to compare the effectiveness of these two antibiotics in eradicating H. pylori in hemodialysis (HD) patients.

Patients and Methods

This is a prospective, randomized, double-blinded clinical trial analysis of HD patients. Patients who had dyspepsia and showed positive results for two of three tests, anti-H. pylori serology, H. pylori stool antigen (HpSAg), or Urease Breath Test (UBT), were included in the study. The subjects consisted of 39 dialysis patients who were randomly divided into two groups that received medication twice daily. Group OAC received 20 mg omeprazol, 500 mg amoxycilin, and 250 mg clarithromycin, and Group OAAz received 20 mg omeprazol, 500 mg amoxicillin, and 250 mg azithromycin. Both regimens were administered for 14 days. Eradication was investigated by performing the UBT and the HpSAg test eight weeks later.

Results

This study began with 39 patients, 37 of which completed the treatment schedule (20 males and 17 females, mean age 59 years). Two patients died due to MI before beginning treatment. In the OAC group, negative results on the UBT and HpSAg tests were found in 82.4% and 88.2% of the participants, respectively. In the OAAz group, these values were 80% and 85%, respectively. The data showed that the difference between the two regimens was not significant (P = 1.0).

Conclusions

According to the data, no differences in eradication rates were apparent between the azitromycin and the claritromycin regimens. However, lower cost and fewer complaints could be considered as an advantage of the triple therapy with azithromycin.

Correlation of Dietary Intakes and Biochemical Determinates of Nutrition in Hemodialysis Patients

OBJECTIVE

The purpose of this study was to determine the effect of dietary intakes on nutritional indicators of patients on hemodialysis.

METHOD

This study was carried out at the hemodialysis unit at the Ministry of Health, Ankara Hospital, from 2003-2004. Sixty-seven patients on regular hemodialysis were enrolled in the study. Nutritional status was assessed by biochemical parameters (urea, uric acid, creatinine, Na, K, Cl, Ca, P, alkaline phosphatase, SGOT, SGPT, cholesterol, total protein, albumin, hemoglobin, hematocrit) and anthropometric measurements (height, dry weight, body mass index), and dietary intakes were calculated.

RESULTS

In this study, the mean age of the patients was 45.3 +/- 13.49, and the duration of hemodialysis was 4.9 +/- 3.64 year. Dialysis time was 12.4 +/- 2.7 h/week. The ratio of individuals with BMI of 20 kg/m2 or below this value was 19.4%. Blood hemoglobin and hematocrit levels were below than the recommended level. Mean serum urea (148.0 +/- 27.76 mg/dL) and creatinine (8.8 +/- 2.13 mg/dL) were found to be high, while a significant negative correlation was found between blood urea level and dietary fat (p < 0.01, r = -0.31). A significant positive correlation was found between vitamin B1, vitamin B6, folate, potassium, iron, and magnesium; between uric acid and vitamin D; between blood creatinine level and dietary vitamin B1, vitamin B6, folate, vitamin C, potassium, iron, magnesium; between blood potassium level and dietary vitamin C only; and between blood cholesterol level and dietary vitamin D only (p < 0.01).

A "weight-listing" paradox for candidates of renal transplantation?

Research suggests that end-stage renal disease patients with elevated body mass index (BMI) have superior outcomes on dialysis. In contrast, low and high BMI patients represent the highest risk cohorts for kidney transplant recipients. The important question remains concerning how to manage transplant candidates given the potentially incommensurate impact of BMI by treatment modality. We conducted a retrospective analysis of waitlisted and transplanted patients in the United States from 1990 to 2003. We constructed Cox models to evaluate the effect of BMI on mortality of waitlisted candidates and identified risk factors for rapid weight change. We then assessed the impact of weight change during waitlisting on transplant outcomes. Decline in BMI on the waiting list was not protective for posttransplant mortality or graft loss across BMI strata. Substantial weight loss pretransplantation was associated with rapid gain posttransplantation. The highest risk for death was among listed patients with low BMI (13-20 kg/m(2), adjusted hazard ratio = 1.47, p < 0.01). Approximately one-third of candidates had a change in BMI category prior to transplantation. While observed declines in BMI may be volitional or markers of disease processes, there is no evidence that candidates have improved transplant outcomes attributable to weight loss. Prospective trials are needed to evaluate the efficacy of weight loss protocols for candidates of kidney transplantation.

Nondiabetic consequences of obesity on kidney

There has been a major increase in obesity among children over the past twenty years. Obesity is associated with glomerular hyperperfusion and hyperfiltration from physiological (mal)adaptation resulting from afferent arteriolar vasodilatation. The renal injury from hyperfiltration in obesity is further exacerbated by concomitant presence of dyslipidemia, hyperglycemia and/or insulin resistance, inflammation and hypertension. The renal injury clinically manifests as microalbuminuria, proteinuria and/or poor renal function, and is histologically characterized by glomerulomegaly, mesangial expansion and/or sclerosis, which has been termed "obesity related glomerulopathy". Obesity portends a poor prognosis in subjects with chronic kidney diseases, IgA nephropathy and nephrectomy. Obese individuals on dialysis and renal transplant have mixed outcomes. The purpose of this review is to highlight the nondiabetic consequences of obesity on kidney for the pediatric nephrology community as we begin to address the obesity epidemic in children.

Interdialytic weight gain as a marker of blood pressure, nutrition, and survival in hemodialysis patients

BACKGROUND

Excessive interdialytic weight gain (IDWG) is usually related to an overload of sodium and water, and is the most important factor for arterial hypertension in dialysis. On the other hand, food intake also contributes to IDWG, and is the basic factor for nutrition. The objective of this study is to assess the long-term prognostic effect of IDWG and its relationship with the nutritional status and blood pressure in patients in hemodialysis (HD).

METHODS

We describe the results of a 5-year prospective observation study in which 134 HD patients were included (70 males and 64 females), with ages between 18 and 81. Initially, the average data were collected during 4 weeks, including total IDWG and percentages according to dry weight (IDWG%), nutritional parameters, and blood pressure. Patients were divided into 3 cohorts according to IDWG% (<2.9, 2.9-3.9, and >3.9%, respectively). Student t test, ANOVA, linear regression analysis, and Kaplan-Meier survival curves compared with log-rank test were used as statistical tools.

RESULTS

The mean IDWG% for the whole studied population was 3.5 +/- 1.1% (1.5-8.0%). It was not related to gender, but had an inverse correlation with age (P < 0.000) and serum bicarbonate level (P= 0.009). It was directly correlated with predialysis systolic and diastolic blood pressure, nPCR, urea and creatinine levels (P < 0.01 for all of them), and the body mass index (P < 0.000). Serum levels of albumin (44.7 +/- 4.0 g/dL) and prealbumin (31.9 +/- 7.4 mg/dL) had a direct correlation with total IDWG (P < 0.01). We found no significant relationship between or IDWG% and ferritin and transferrin levels. Five-year actuarial survival was 0.38, 0.52, and 0.63, respectively, in the 3 cohorts for IDWG% (P < 0.01).

CONCLUSION

Our results show that a greater IDWG is directly associated with a better nutritional status, although it is also associated with higher predialysis blood pressure. The greater the IDWG%, the better the long-term prognosis of the patients. The beneficial effects of IDWG on the nutritional status and prognosis are greater than the negative aspects that depend on its effects on blood pressure. One must distinguish clearly between some isolated instances of not complying with a diet from those situations where a higher IDWG is merely a reflection of a good nutritional status, and one must be careful so that dietary recommendations will not have a negative influence on nutritional aspects. One must watch and correct the trend towards higher acidosis in patients with a greater IDWG.

The influence of obesity on the development and survival outcomes of chronic kidney disease

The prevalence of obesity, defined as a body mass index (BMI) greater than 30 kg/m2 , has more than doubled in many Western countries over the past 2 decades and has become a major public health challenge. This epidemic of obesity in developed countries has been matched closely by alarming increases in the incidence of diabetes mellitus, hypertension, chronic kidney disease (CKD), and cardiovascular disease. However, the exact role that increased body size plays in the development of nephropathy and its subsequent contribution to cardiovascular morbidity and mortality remain unclear. For example, whether obesity per se is a risk factor for CKD independent of diabetes mellitus and hypertension is uncertain. Moreover, in patients with end-stage kidney disease, strong evidence suggests that obesity may paradoxically enhance patient survival. This review will focus on the evidence for obesity as an independent risk factor for the development and progression of CKD and as a paradoxical survival factor in patients with end-stage kidney failure. Possible mechanisms underlying these observed associations will be discussed.