Associations of body fat and its changes over time with quality of life and prospective mortality in hemodialysis patients

Association of sarcopenic obesity predicted by anthropometric measurements and 24-y all-cause mortality in elderly men: The Kuakini Honolulu Heart Program

OBJECTIVE

The aim of this study was to investigate the association between anthropometric measurements of sarcopenic obesity and all-cause mortality.

METHODS

The study included 2309 Japanese-American men ages 71 to 93 y. Mortality data were available for up to 24 y of follow-up. Sarcopenic obesity defined by three patterns of obesity indexes (body mass index [BMI], percent body fat [%BF] and waist circumference [WC]) and skeletal muscle index estimated by anthropometric measurements.

RESULTS

Of the 2309 participants, 2210 deaths were reported during the mean follow-up period of 11.7 y. Risk for death was significantly increased with sarcopenia after adjusting for baseline age, lifestyle variables, hypertension, diabetes, and cognitive scores (hazard ratio [HR], 1.26; 95% confidence interval [CI], 1.15-1.38). Risk for death was significantly decreased with obesity using WC and %BF to define obesity, but not BMI. Risk for death also was significantly increased in the sarcopenia group compared with the optimal group, regardless of which pattern of obesity indexes (BMI, %BF, and WC) was used. Risk for death was significantly increased in sarcopenic obesity defined by WC (HR, 1.19; 95% CI, 1.02-1.38), borderline in the BMI-defined group, and not significant in the %BF-defined group.

CONCLUSION

All-cause mortality was increased in men with sarcopenic obesity defined by WC, but not BMI and %BF. Sarcopenia was a stronger predictor of all-cause mortality in this cohort >70 y of age. These results suggest that anthropometric definitions for sarcopenia and sarcopenic obesity are clinically useful as a predictor of all-cause mortality.

The Relationship Between Nephrolithiasis Risk with Body Fat Measured by Body Composition Analyzer in Obese People

BACKGROUND

Nephrolithiasis (kidney stones) continues to be a major cause of morbidity and healthcare spending that visceral and subcutaneous adipose tissue may associate with kidney stone formation. This study aimed to investigate the relationship between nephrolithiasis with visceral fat scale in obese people in Western Iran for the first time.

MATERIALS AND METHODS

In 2017, 103 participants with BMI≥30 kg/m² were selected for the present study. The participants were divided into two groups, 52 as case group (having the kidney stone) and 58 as healthy control group (no kidney stone or history of the kidney stone or any other disease). The levels of body composition were checked by body composition analyzer (BoCA x1) based on Bio Impedance mechanism.

RESULTS

Two groups were matched in terms of sex and BMI. There was a significant difference between two groups for the visceral fat to subcutaneous fat ratio (VSR) that accordingly, the mean VSR in the case group was higher than the control group. The difference for other variables between two groups was not significant.

CONCLUSIONS

The results showed that visceral and subcutaneous fat and VSR were important risk factors for kidney stone formation (nephrolithiasis). Evaluating these fats in stone formers may facilitate a tailored metabolic evaluation and treatment plan.

The relationship of serum adipokines with malnutrition inflammation score in haemodialysis

BACKGROUND

Protein-energy wasting is a prevalent disorder in haemodialysis. Zinc-α2-glycoprotein (ZAG) and adipose triglyceride lipase (ATGL) are novel adipokines with recognized lipolytic effects and proposed role in metabolic homoeostasis. This study was conducted to investigate the association of ZAG and ATGL concentrations with malnutrition-inflammation score (MIS) and metabolic profile of patients with haemodialysis.

MATERIALS AND METHODS

Eighty-eight patients under regular haemodialysis were divided based on MIS to normal to mild wasting (NMW; n = 35) or moderate wasting (MW; n = 53) group. Anthropometric measurements along with fasting serum concentrations of ZAG, ATGL, free fatty acids (FFAs), albumin, transferrin, total iron-binding capacity (TIBC), hs-CRP, lipid profile and glucose metabolism were assessed.

RESULTS

Adipose triglyceride lipase concentration was significantly higher in MW than NMW group (10·89 ± 5·7 vs. 8·02 ± 3·37 mIU/mL; P = 0·008). The ZAG and FFAs were not significantly different between two groups. ATGL was directly correlated with FFAs in all of the patients (r = 0·284, P = 0·007) and MW (r = 0·32, P = 0·021), and marginally in NMW (r = 0·31, P = 0·057) groups. ATGL and odds of having mild or moderate wasting were significantly correlated (OR = 1·21, P = 0·033). A positive association was observed between ATGL with TG (r = 0·31, P = 0·049) and also with transferrin and TIBC (r = 0·44, P = 0·001) only in MW group. An inverse relationship was observed between ATGL and HDL in all of the participants (r=-0·222, P = 0·04). No significant correlation was observed between ZAG and other parameters.

CONCLUSIONS

The serum concentrations of ATGL, but not ZAG, were significantly higher in MW compared to NMW group. Each unit increase in ATGL concentrations was correlated with 21% increase in the odds of wasting severity. ATGL might play a role in wasting pathogenesis and metabolic profile in haemodialysis.

Obesity and kidney disease: Hidden consequences of the epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease (CKD). A high body mass index is one of the strongest risk factors for new-onset CKD. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing CKD in the long-term. The incidence of obesity-related glomerulopathy has increased tenfold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle, and health policy measures that makes preventive behaviors an affordable option.

Thyroid Status and Mortality in a Prospective Hemodialysis Cohort

CONTEXT AND OBJECTIVE

Compared with the general population, hemodialysis patients have a substantially higher risk of hypothyroidism, as defined by an elevated serum thyrotropin (TSH) level, and cardiovascular mortality. Whereas an elevated TSH is associated with cardiovascular disease and death in the general population, associations among dialysis patients have been inconsistent.

DESIGN, SETTING, PARTICIPANTS, AND MAIN OUTCOME

We examined 541 hemodialysis patients from 17 southern California dialysis centers in the prospective Hypothyroidism, Cardiovascular Health, and Survival study who underwent protocolized measurement of repeated serum TSH levels every 6 months from 2013 to 2015. Associations between TSH tertiles (<1.28, 1.28 to <2.14, and 2.14 to 86.7 mIU/L) and mortality were estimated using time-dependent Cox models with four adjustment levels. In sensitivity analyses, we excluded patients receiving thyroid hormone supplementation.

RESULTS

Compared with the lowest TSH tertile, the highest TSH tertile was associated with a 2.2- to 2.5-fold higher mortality risk in unadjusted, case-mix, expanded case-mix+laboratory, and expanded case-mix+laboratory+medication models [hazard ratios (95% confidence interval), 2.54 (1.32 to 4.89), 2.53 (1.30 to 4.93), 2.19 (1.11 to 4.32), and 2.28 (1.45 to 3.58), respectively]. We observed a consistent trend between higher TSH tertiles and numerically higher mortality risk across all models. Similar findings were observed in analyses excluding patients receiving thyroid hormone supplementation.

CONCLUSION

In time-dependent analyses, TSH levels in the high-normal to high range were independently associated with higher death risk in hemodialysis patients. Further studies are indicated to determine whether normalization of TSH levels with thyroid hormone supplementation improves survival in this population.

Obesity and kidney disease: hidden consequences of the epidemic

Obesity has become a worldwide epidemic and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease and also for chronic kidney disease (CKD). A high body mass index is one of the strongest risk factors for new-onset CKD. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing CKD in the long-term. The incidence of obesity-related glomerulopathy has increased ten-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year, the World Kidney Day will promote education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

Body mass index is inversely associated with mortality in patients with acute kidney injury undergoing continuous renal replacement therapy

BACKGROUND

Many epidemiologic studies have reported on the controversial concept of the obesity paradox. The presence of acute kidney injury (AKI) can accelerate energy-consuming processes, particularly in patients requiring continuous renal replacement therapy (CRRT). Thus, we aimed to investigate whether obesity can provide a survival benefit in this highly catabolic condition.

METHODS

We conducted an observational study in 212 patients who had undergone CRRT owing to various causes of AKI between 2010 and 2014. The study end point was defined as death that occurred within 30 days after the initiation of CRRT.

RESULTS

Patients were categorized into three groups according to tertiles of body mass index (BMI). During ≥30 days after the initiation of CRRT, 39 patients (57.4%) in the highest tertile died, as compared with 58 patients (78.4%) in the lowest tertile (P = 0.02). In a multivariable analysis adjusted for cofounding factors, the highest tertile of BMI was significantly associated with a decreased risk of death (hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.37-0.87; P = 0.01). This significant association remained unaltered for 60-day (HR, 0.64; 95% CI, 0.43-0.94; P = 0.03) and 90-day mortality (HR, 0.66; 95% CI, 0.44-0.97; P = 0.03).

CONCLUSION

This study showed that a higher BMI confer a survival benefit over a lower BMI in AKI patients undergoing CRRT.

Increased mid-abdominal circumference is a predictor for surgical wound complications in kidney transplant recipients: A prospective cohort study

Kidney transplant recipients are at an increased risk of developing surgical site wound complications due to their immunosuppressed status. We aimed to determine whether increased mid-abdominal circumference (MAC) is predictive for wound complications in transplant recipients. A prospective study was performed on all kidney transplant recipients from October 2014 to October 2015. "Controls" consisted of kidney transplant recipients without a surgical site wound complication and "cases" consisted of recipients that developed a wound complication. In total, 144 patients underwent kidney transplantation and 107 patients met inclusion criteria. Postoperative wound complications were documented in 28 (26%) patients. Patients that developed a wound complication had a significantly greater MAC, body mass index (BMI), and body weight upon renal transplantation (P<.001, P=.011, and P=.011, respectively). On single and multiple logistic regression analyses, MAC was a significant predictor for developing a surgical wound complication (P=.02). Delayed graft function and a history of preformed anti-HLA antibodies were also predictive for surgical wound complications (P=.003 and P=.014, respectively). Increased MAC is a significant predictor for surgical wound complications in kidney transplant recipients. Integrating clinical methods for measuring visceral adiposity may be useful for stratifying kidney transplant recipients with an increased risk of a surgical wound complication.

Obesity and Kidney Disease: Hidden Consequences of the Epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease (CKD). A high body mass index is one of the strongest risk factors for new-onset CKD. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing CKD in the long term. The incidence of obesity-related glomerulopathy has increased 10-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

The Obesity Paradox in Kidney Disease: How to Reconcile it with Obesity Management

Obesity, a risk factor for de novo chronic kidney disease (CKD), confers survival advantages in advanced CKD. This so-called obesity paradox is the archetype of the reverse epidemiology of cardiovascular risks, in addition to the lipid, blood pressure, adiponectin, homocysteine, and uric acid paradoxes. These paradoxical phenomena are in sharp contradistinction to the known epidemiology of cardiovascular risks in the general population. In addition to advanced CKD, the obesity paradox has also been observed in heart failure, chronic obstructive lung disease, liver cirrhosis, and metastatic cancer, as well as in the elderly. These are populations in whom protein-energy wasting and inflammation are strong predictors of early death. Both larger muscle mass and higher body fat provide longevity in these patients, whereas thinner body habitus and weight loss are associated with higher mortality. Muscle mass appears to be superior to body fat in conferring an even greater survival. The obesity paradox may be the result of a time discrepancy between competing risk factors, i.e., overnutrition as the long-term killer versus undernutrition as the short-term killer. Hemodynamic stability of obesity, lipoprotein defense against circulating endotoxins, protective cytokine profiles, toxin sequestration of fat mass, and antioxidation of muscle may play important roles. Despite claims that obesity paradox is a statistical fallacy and a result of residual confounding, the consistency of data and other causality clues suggest a high biologic plausibility. Examining the causes and consequences of the obesity paradox may help discover important pathophysiologic mechanisms leading to improved outcomes in patients with CKD.

Obesity and kidney disease: hidden consequences of the epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease and also for chronic kidney disease. A high BMI is one of the strongest risk factors for new-onset chronic kidney disease. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing chronic kidney disease in the long-term. The incidence of obesity-related glomerulopathy has increased tenfold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

Obesity and Kidney Disease: Hidden Consequences of the Epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease, and also for chronic kidney disease. A high body mass index is one of the strongest risk factors for new-onset chronic kidney disease. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing chronic kidney disease in the long-term. The incidence of obesity-related glomerulopathy has increased 10-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year, the World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyle and health policy measures that make preventive behaviors an affordable option.

Obesity and kidney disease: hidden consequences of the epidemic

Obesity has become a worldwide epidemic, and its prevalence has been projected to grow by 40% in the next decade. This increasing prevalence has implications for the risk of diabetes, cardiovascular disease and also for chronic kidney disease (CKD). A high body mass index is one of the strongest risk factors for new-onset CKD. In individuals affected by obesity, a compensatory hyperfiltration occurs to meet the heightened metabolic demands of the increased body weight. The increase in intraglomerular pressure can damage the kidneys and raise the risk of developing CKD in the long term. The incidence of obesity-related glomerulopathy has increased 10-fold in recent years. Obesity has also been shown to be a risk factor for nephrolithiasis, and for a number of malignancies including kidney cancer. This year World Kidney Day promotes education on the harmful consequences of obesity and its association with kidney disease, advocating healthy lifestyles and health policy measures that make preventive behaviors an affordable option.

Changes in Body Composition in the Two Years after Initiation of Haemodialysis: A Retrospective Cohort Study

Malnutrition is common in haemodialysis (HD) and is linked to poor outcomes. This study aimed to describe changes in body composition after the initiation of HD and investigate whether any routinely collected parameters were associated with these changes. The study cohort came from the HD population of a single centre between 2009 and 2014. Body composition measurements were obtained from a database of bioimpedance results using the Body Composition Monitor (BCM), while demographics and laboratory values came from the renal unit database. Primary outcomes were changes in normohydration weight, lean tissue mass and adipose tissue mass over the two years after HD initiation. A total of 299 patients were included in the primary analyses, showing an increase in adipose tissue, loss of lean tissue and no significant change in normohydration weight. None of the routinely collected parameters were associated with the lean tissue changes. Loss of lean tissue over the first year of dialysis was associated with increased mortality. The results showing loss of lean tissue that is not limited to those traditionally assumed to be at high risk supports interventions to maintain or improve lean tissue as soon as possible after the initiation of HD. It highlights the importance of monitoring nutrition and the potential for routine use of bioimpedance.

Lower thigh muscle mass is associated with all-cause and cardiovascular mortality in elderly hemodialysis patients

BACKGROUND/OBJECTIVES

Higher body mass index appears protective in hemodialysis patients, although it remains to be determined which component of muscle or fat mass is primarily associated with this survival advantage.

SUBJECTS/METHODS

Eighty-one hemodialysis patients in our institution were prospectively followed from July 2011 to August 2015. Muscle and fat mass were evaluated by measuring the cross-sectional areas of the thigh and abdomen using computed tomography. The relationship between muscle and fat mass, and all-cause and cardiovascular mortality was studied using the Kaplan-Meier analyses and multivariate Cox proportional hazard models.

RESULTS

During more than 4 years of follow-up, 26 patients (32%) died. In the Kaplan-Meier curve analyses, lower thigh muscle mass was significantly associated with all-cause and cardiovascular mortality (log-rank test, P<0.01 and P<0.001, respectively), but there was no such association with thigh fat, abdominal muscle and fat mass levels. In multivariate Cox proportional hazard models, each 0.1 cm²/kg increase in the thigh muscle area adjusted by dry weight was associated with an estimated 22% lower risk of all-cause mortality (95% confidence interval (95% CI), 0.64-0.95, P<0.05) and a 30% lower risk of cardiovascular mortality (95% CI, 0.54-0.90, P<0.01).

CONCLUSIONS

Lower thigh muscle mass is significantly associated with all-cause and cardiovascular mortality in hemodialysis patients. Our findings indicate the importance of focusing on the muscle mass of lower extremities to predict the clinical outcomes of hemodialysis patients.

Hidden Obesity in Dialysis Patients: Clinical Implications

While body-mass index (BMI) is used to diagnose obesity in the general population, its application in the end-stage renal disease (ESRD) population is fraught with difficulty. A major limitation is its inability to distinguish muscle mass from fat mass, thereby leading to misclassification of individuals with poor muscle mass but excess adipose tissue as non-obese (i.e. BMI <30 kg/m(2) ). As muscle wasting is common among ESRD patients, this is an important problem. A substantial proportion of ESRD patients have levels of BMI in the normal range, yet excess adiposity based on other measures. The importance of this "hidden" obesity remains to be determined, but it must be recognized in order for obesity interventions to be appropriately targeted and tested in the ESRD population.

Body composition in chronic kidney disease

PURPOSE OF REVIEW

To summarize the latest information on body composition among patients with chronic kidney disease and its association with outcomes.

RECENT FINDINGS

Obesity is increasing among patients with end-stage renal disease and is more prevalent when direct measures of adiposity are used rather than BMI. High BMI is not associated with better survival among patients with earlier chronic kidney disease or after kidney transplantation, suggesting that excess fat is most protective among the sickest patients. Despite the positive association between BMI and survival among patients with end-stage renal disease, visceral fat is associated with coronary artery calcification and adverse cardiovascular events. Muscle wasting is prominent among patients with chronic kidney disease, sometimes even in the setting of obesity. Obesity and muscle wasting are associated with worse physical functioning. Indicators of low muscle size and strength are associated with higher mortality. Some interventions can affect body composition, but whether they affect survival has not been determined.

SUMMARY

Recent studies show that a high BMI is not protective for all patients with chronic kidney disease and is associated with poor physical functioning and frailty. Visceral adiposity is associated with adverse cardiovascular outcomes. Sarcopenia is common among patients with end-stage renal disease and is associated with worse physical performance and higher mortality.

Body Composition and Mortality Predictors in Hemodialysis Patients

OBJECTIVE

To evaluate how different compartments of body composition can affect survival in hemodialysis (HD) patients.

DESIGN

Multicenter longitudinal observational study of a cohort of patients in HD with 12 months of follow-up.

SETTING

Patients from 34 Nephrocare dialysis units in Portugal were included.

SUBJECTS

A total of 697 patients on maintenance HD during 4 hours 3 days per week were enrolled.

INTERVENTION

Dry weight, presence of diabetes, body mass index (BMI), lean tissue index (LTI), fat tissue index (FTI), body cell mass index (BCMI), albumin and hydration status were recorded at baseline. In all patients, the assessment of body composition was carried out using the Body Composition Monitor (BCM; Fresenius Medical Care a Deutschland GmbH, Germany).

MAIN OUTCOME MEASURE

Survival during a 12-month period of follow-up.

RESULTS

Patient's mean (±standard deviation) age was 65.4 ± 14.3 years, and median (interquartile range) HD vintage was 41 (19-81) months. Patients who died during the study period, had higher age (P < .001), lower dry weight (P = .001), BMI (P < .001), albumin (P < .001), LTI (P = .015), and also lower BCMI (P = .046). Patients with diabetes (P = .045), BMI < 18.5 kg/m(2) (P < .001), albumin < 4.0 g/dL (P < .001), relative overhydration ≥ 15% (P = .001), low FTI (P = .019), and also those in the lowest tertile of BCMI (P = .022) displayed a significantly worse survival. In the Cox regression analysis, the overall mortality of patient was related to low FTI, relative overhydration, BMI < 18.5 kg/m(2), BCMI ≤ 5.2 kg/m(2), and albumin < 4.0 g/dL.

CONCLUSIONS

Several body composition parameters demonstrated to have an important role in predicting 1-year mortality in HD patients. Albumin, FTI, and BMI were useful predictors of mortality in these patients.

Lean Body Mass and Survival in Hemodialysis Patients and the Roles of Race and Ethnicity

BACKGROUND

Lean body mass (LBM) represents the "fat-free" muscle mass in hemodialysis (HD) patients and is an important nutritional measure. Previous studies have found that both higher LBM and body mass index (BMI) were related to greater survival in HD patients. Additional studies have shown differences in survival across racial-ethnic groups of HD patients. However, the association of LBM and mortality across racial-ethnic subgroups has not been examined.

OBJECTIVE

We hypothesize that racial differences in LBM affect the mortality in HD patients.

SETTING AND SUBJECTS

Chronic HD patients from a large dialysis organization in the United States.

PREDICTORS

Estimated LBM (eLBM), self-identified racial subgroups.

MAIN OUTCOME MEASURE

5-year survival.

STUDY DESIGN

We examined the association between baseline eLBM and survival using Cox proportional hazard models adjusted for demographics, comorbidities, and laboratory measures. Associations were examined across subgroups of race-ethnicity (non-Hispanic white, African American, and Hispanic) and BMI.

RESULTS

The final cohort included 117,683 HD patients, who were 62 ± 15 (mean ± standard deviation) years old, 43% women and 59% with diabetes mellitus. Higher eLBM was linearly associated with lower mortality. Compared with the reference group (48.4-<50.5 kg), patients with the lowest eLBM (<41.3 kg) had a 1.4-fold higher risk of mortality (hazard ratio: 1.37; 95% confidence interval: 1.30-1.44) in the fully adjusted model. A similar linear association was seen among patients with BMI < 35 kg/m(2) and in non-Hispanic whites and African American subgroups. However, higher eLBM was not associated with improved survival in Hispanic patients or patients with BMI ≥ 35 kg/m(2).

LIMITATION

Potential residual confounding.

CONCLUSIONS

Higher eLBM is associated with a lower mortality risk in HD patients, especially among non-Hispanic white and African American groups. Hispanic patients do not demonstrate a similar inverse relationship. The association between LBM and mortality among different racial groups of HD patients deserves additional study.

The associations of "fatness," "fitness," and physical activity with all-cause mortality in older adults: A systematic review

OBJECTIVE

This review explored whether cardiorespiratory fitness or physical activity act as either confounders or effect modifiers of the relationship between adiposity markers and all-cause mortality in older adults.

METHODS

Systematic searches were carried out to identify observational studies that examined the association of adiposity markers (BMI, waist circumference, and waist-hip ratio) with all-cause mortality in adults aged ≥ 60 which took into account cardiorespiratory fitness or physical activity. Data from each included study was analyzed to produce a graphical representation of this relationship.

RESULTS

Fourteen of the fifteen identified studies found that increasing BMI had a non-positive association with all-cause mortality, with persistence of the obesity paradox despite adjustment for physical activity or cardiorespiratory fitness. Physical activity measurement methods were all subjective and often unvalidated. The two studies stratifying for cardiorespiratory fitness did not find that fitness had a significant impact on the relationship between excess adiposity and mortality but found that overweight and fit people had better survival than normal-weight unfit people,

CONCLUSIONS

The predominant use of poor physical activity measurement suggests that studies are currently not adequately accounting for possible physical activity confounding. More studies are needed for addressing the modification of the relationship between adiposity markers and mortality by cardiorespiratory fitness.

Association of age and BMI with kidney function and mortality: a cohort study

BACKGROUND

Compared with normal weight, obesity might be associated with worse clinical outcomes, including chronic kidney disease. Whether this association is modified by age is not known. We investigated the association of BMI with progressive loss of kidney function and all-cause mortality in US veterans.

METHODS

In a national cohort of 3,376,187 US veterans with an estimated glomerular filtration rate (eGFR) of more than 60 mL/min per 1·73 m(2), we assessed the association of BMI in patients of different ages (<40 years, 40 years to <50 years, 50 years to <60 years, 60 years to <70 years, 70 years to <80 years, and ≥80 years) with loss of kidney function and with all-cause mortality in logistic regression models and Cox proportional hazards models adjusted for ethnic origin, sex, comorbidities, medications, and baseline eGFR.

FINDINGS

274,764 (8·1%) of 3,376,187 veterans had a rapid decline in kidney function (decrease in slope of >5 mL/min per 1·73 m(2)). The lowest risk for loss of kidney function was noted in patients with BMI of at least 25 kg/m(2) but less than 30 kg/m(2). A generally consistent U-shaped association was noted between BMI and rapid loss of kidney function that was more prominent with increasing age, except in the patients younger than 40 years, in whom BMI did not seem to be predictive of renal function impairment. 672,341 veterans died (28·7 per 1000 patient-years, 95% CI 28·6-28·7) over a median follow-up of 6·8 years (IQR 6·5-7·7). BMI also showed a U-shaped association with mortality, which was similar in all age groups.

INTERPRETATION

A BMI of 30 kg/m(2) or more is associated with rapid loss of kidney function in patients with eGFR of at least 60 mL/min per 1·73 m(2), and this association is accentuated in older patients. A BMI of 35 kg/m(2) or more is also associated with high mortality. A BMI of at least 25 kg/m(2) but less than 30 kg/m(2) is associated with the best clinical outcomes.

FUNDING

National Institute of Health, Memphis VA Medical Center, Long Beach VA Healthcare System, Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development, Health Services Research and Development, and VA Information Resource Center.

Malnutrition in Dialysis Patients--The Need for Intervention Despite Uncertain Benefits

We are in the midst of an epidemic of overnutrition which has resulted in a widespread increase in obesity rates in modern societies. Yet for patients suffering from serious chronic illnesses such as end stage renal disease (ESRD), malnutrition (encompassing both inadequate quantity and quality of nutrient intake) represents a far more significant danger. Protein-energy wasting has been identified as one of the strongest risk factor for adverse outcomes in ESRD patients, and modeling studies have suggested that improving nutrition could result in substantial lowering of mortality rates and other benefits. To date there is ample evidence that various interventions can have a positive impact on the nutritional status of ESRD patients, yet we still lack randomized controlled clinical trials showing that the same interventions could indeed lead to better survival or other clinical benefits. This knowledge gap, which is all too common for clinical problems encountered in nephrology, should not act as a deterrent, but it should rather incentivize us to continue exploring novel interventions aimed at improving malnutrition in ESRD.

Body mass index, mortality, and gender difference in advanced chronic kidney disease

BACKGROUND AND AIM

A higher body mass index (BMI) appears to be reversely associated with mortality in dialysis patients. Moreover, although women have better survival in chronic kidney disease (CKD), this survival advantage is cancelled in dialysis. The association between BMI and mortality and the gender difference remain controversial in advanced CKD.

METHODS

This study enrolled 3,320 patients (1,938 men and 1,382 women) from southern Taiwan who had CKD stages 3-5 with a BMI of 15.0-35.0 kg/m2.

RESULTS

During a median 2.9-year follow-up, there were 328 (16.9%) all-cause mortality and 319 (16.5%) cardiovascular (CV) events and death in male patients, 213 (15.4%) all-cause mortality and 224 (16.2%) CV events and death in female patients. Compared with the reference BMI of 27.6-30.0 kg/m2 in an adjusted Cox model, lower-BMI groups in men, BMI 15.0-20.0 kg/m2 and 20.1-22.5 kg/m2, were associated with higher risks of all-cause mortality: hazard ratios (HRs) 3.19 (95% confidence interval [CI], 1.97-5.18) and 2.01 (95% CI, 1.29-3.14), respectively. Higher-BMI group in men, BMI 30.1-35.0 kg/m2, was associated with a higher risk of all-cause mortality: HR 1.72 (95% CI, 1.02-2.96). Likewise, lower- and higher-BMI groups in men were associated with a higher risk of CV events and death. In women, these associations between BMI and poor outcomes were not observed.

CONCLUSIONS

In advanced CKD, there was a reverse J-shaped association between BMI and all-cause mortality, and a U-shaped association between BMI and CV outcomes in men. Neutral associations between BMI and poor outcomes were detected in women. Gender could modify the effect of BMI on mortality in patients with CKD.

Association of Adiponectin With Body Composition and Mortality in Hemodialysis Patients

BACKGROUND

In the general population, circulating adiponectin is associated with a favorable cardiovascular risk profile (eg, lower triglycerides and body fat) and decreased mortality. Hemodialysis (HD) patients have comparatively higher adiponectin concentrations, but prior studies examining the adiponectin-mortality association in this population have not accounted for body composition or shown a consistent relationship.

STUDY DESIGN

Prospective cohort study.

SETTINGS & PARTICIPANTS

We examined baseline serum adiponectin concentrations in 501 HD patients across 13 dialysis centers from the prospective MADRAD (Malnutrition, Diet, and Racial Disparities in Chronic Kidney Disease) cohort (entry period, October 2011 to February 2013; follow-up through August 2013).

PREDICTOR

Serum adiponectin concentration in tertiles (tertiles 1, 2, and 3 defined as ≤16.1, >16.1-<30.1, and ≥30.1-100.0 μg/mL, respectively). Adjustment variables included case-mix and laboratory test results (age, sex, race, ethnicity, vintage, diabetes, serum albumin, total iron-binding capacity, serum creatinine, white blood cell count, phosphate, hemoglobin, and normalized protein catabolic rate), body composition surrogates (subcutaneous, visceral, and total-body fat and lean body mass), and serum lipid levels (cholesterol, high-density lipoprotein cholesterol, and triglycerides).

OUTCOMES

All-cause mortality using survival (Cox) models incrementally adjusted for case-mix and laboratory test results.

RESULTS

Among 501 HD patients, 50 deaths were observed during 631.1 person-years of follow-up. In case-mix- and laboratory-adjusted Cox analyses, the highest adiponectin tertile was associated with increased mortality versus the lowest tertile (HR, 3.35; 95% CI, 1.50-7.47). These associations were robust in analyses that additionally accounted for body composition (HR, 3.18; 95% CI, 1.61-8.24) and lipid levels (HR, 3.64; 95% CI, 1.34-7.58).

LIMITATIONS

Residual confounding cannot be excluded.

CONCLUSIONS

Higher adiponectin level is associated with a 3-fold higher death risk in HD patients independent of body composition and lipid levels. Future studies are needed to elucidate underlying mechanisms and determine therapeutic targets associated with improved outcomes in HD patients.

Effect of personalized nutritional counseling in maintenance hemodialysis patients

Monitoring nutritional parameters is an integral part of hemodialysis (HD) patient treatment program. The purpose of this study was to evaluate the impact of the personalized nutritional counseling (PNC) on calcium-phosphorus metabolism, potassium, albumin, protein intake, interdialytic weight gain (IDWG), body composition parameters and fluid overload in HD patients. This was a multicenter longitudinal intervention study with 6 months of follow-up and 731 patients on maintenance HD from 34 dialysis units in Portugal were enrolled. Biochemical and body composition parameters were measured at baseline, 1, 3 and 6 months after the PNC. Patient's mean age was 64.9 (95% confidence interval [CI]: 63.8-66.0) years and mean HD time was 59.8 (95% CI: 55.3-64.3) months. Regarding data comparison collected before PNC vs. 6 months after, we obtained, respectively, the following results: patients with normalized protein catabolic rate (nPCR) ≥ 1 g/kg/day = 66.5% vs. 73.5% (P = 0.002); potassium > 5.5 mEq/L = 52% vs. 35.8% (P < 0.001); phosphorus between 3.5 and 5.5 mg/dL = 43.2% vs. 52.5% (P < 0.001); calcium/phosphorus (Ca/P) ratio ≤ 50 mg/dL = 73.2 % vs. 81.4% (P < 0.001); albumin ≥ 4.0 g/dL = 54.8% vs. 55% (P = 0.808); presence of relative overhydration = 22.4% vs. 25% (P = 0.283); IDWG > 4.5% = 22.3% vs. 18.2% (P = 0.068). PNC resulted in a significant decrease in the prevalence of hyperkalemia, hypophosphatemia and also showed amelioration in Ca/P ratio, nPCR and an increase in P of hyphosphatemic patients. Our study suggests that dietetic intervention contributes to the improvement of important nutritional parameters in patients receiving hemodialysis treatment.

The predictive value of composite methods of nutritional assessment on mortality among haemodialysis patients

BACKGROUND & AIMS

Several parameters might indicate protein-energy wasting in patients undergoing haemodialysis (HD), and such depletion has been associated with the survival of these patients. Our aim was to identify the parameters that are associated with an increased risk of death among HD patients.

METHODS

This was a prospective study with at least 13 months follow-up three times per week of 138 HD patients; 61.6% of the patients were men, 28.9% had diabetes mellitus, and 81.9% had hypertension. The associations of the survival rates based on by Kaplan-Meier analysis with the following nutritional parameters were verified: albumin, lymphocytes, % fat mass (% FM), mid-arm muscle circumference (MAMC), subjective global assessment (SGA), malnutrition-inflammation score (MIS), and nutritional risk screening 2002 (NRS 2002). Cox proportional hazard analysis was used to identify the patients' risk of death (hazard proportional ratio - HR).

RESULTS

The nutritional parameters of lymphocytes and % FM were not associated with the risk of patient death. The patients who were classified as malnourished based on MAMC had a greater risk of death than did those considered nourished, but this difference was not statistically significant. The parameters of serum albumin, SGA, MIS, and NRS 2002 were associated with the risk of patient death (HR = 2.77 P = 0.042, HR = 1.88 P = 0.202, HR = 4.47 P = 0.011, HR = 3.13 P = 0.022, respectively), and the latter two parameters were significantly associated with a high risk among malnourished.

CONCLUSIONS

The scores for the MIS and NRS 2002 composite methods of nutritional assessment were associated with the highest mortality risk values; thus, in conditions similar to those of our study, we suggest that the use of these parameters should be preferred.

Relationship between mortality and BMI after fracture: a population-based study of men and women aged ≥40 years

Fractures in obese older individuals contribute significantly to the overall burden on primary health care, but data on their impact on mortality are lacking. We studied the association between obesity and mortality following hip and nonhip clinical fractures in a retrospective, population-based cohort study. The Sistema d'Informació pel Desenvolupament de la Investigació en Atenció Primària (SIDIAP(Q) ) database contains primary care computerized medical records of a representative sample of >2.1 million people (35% of the population) in Catalonia (Spain), linked to hospital admissions data. We included in this analysis anyone aged 40 years and older suffering a hip or nonhip clinical fracture in 2007 to 2009 in the SIDIAP(Q) database. The main exposure was the most recent body mass index (BMI) measured before fracture, categorized as underweight (<18.5 kg/m2), normal (18.5 to <25 kg/m2 ), overweight (25 to <30 kg/m2), and obese (≥30 kg/m2). Furthermore, the study outcome was all-cause mortality in 2007 to 2009 as provided to SIDIAP(Q) by the National Office of Statistics. Time to death after fracture was modeled using Cox regression. Multivariate models were adjusted for age, gender, smoking, alcohol intake, oral glucocorticoid use, and Charlson comorbidity index. Within the study period, 6988 and 29,372 subjects with a hip or nonhip clinical fracture were identified and followed for a median (interquartile range) of 1.17 (0.53-2.02) and 1.36 (0.65-2.15) years, respectively. Compared to subjects of normal weight, adjusted hazard ratios (HRs) for mortality in overweight and obese subjects were 0.74 (95% CI, 0.62-0.88; p = 0.001) and 0.74 (95% CI, 0.60-0.91; p = 0.004) after hip and 0.50 (95% CI, 0.32-0.77; p = 0.002), 0.56 (95% CI, 0.36-0.87; p = 0.010) after nonhip fracture. In conclusion, the highest mortality was observed in individuals with low BMI, but compared to subjects of normal weight, obese and overweight individuals survived longer following fracture. The latter observation is consistent with data reported in other chronic conditions, but the reasons for reduced mortality in obese and overweight subjects when compared to those of normal weight require further research.

Association of body mass index with outcomes in patients with CKD

Obesity is associated with higher mortality in the general population, but this association is reversed in patients on dialysis. The nature of the relationship of obesity with adverse clinical outcomes in nondialysis-dependent CKD and the putative interaction of the severity of disease with this association are unclear. We analyzed data from a nationally representative cohort of 453,946 United States veterans with eGFR<60 ml/min per 1.73 m(2). The associations of body mass index categories (<20, 20 to <25, 25 to <30, 30 to <35, 35 to <40, 40 to <45, 45 to <50, and ≥50 kg/m(2)) with all-cause mortality and disease progression (using multiple definitions, including incidence of ESRD, doubling of serum creatinine, and the slopes of eGFR) were examined in Cox proportional hazards models and logistic regression models. Multivariable adjustments were made for age, race, comorbidities and medications, and baseline eGFR. Body mass index showed a relatively consistent U-shaped association with clinical outcomes, with the best outcomes observed in overweight and mildly obese patients. Body mass index levels <25 kg/m(2) were associated with worse outcomes in all patients, independent of severity of CKD. Body mass index levels ≥35 kg/m(2) were associated with worse outcomes in patients with earlier stages of CKD, but this association was attenuated in those patients with eGFR<30 ml/min per 1.73 m(2). Thus, until clinical trials establish the ideal body mass index, a cautious approach to weight management is warranted in this patient population.

Anthropometrics Identify Wasting in Patients Undergoing Surgery for Encapsulating Peritoneal Sclerosis

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INTRODUCTION

Encapsulating peritoneal sclerosis (EPS) is a serious complication of peritoneal dialysis in which gastrointestinal (GI) symptoms reduce appetite and dietary intake. Adequate nutrition is important, especially if surgery is required. Although the incidence of EPS is low, the present report is able to detail preoperative nutrition status and treatment in a large cohort of patients from a national EPS referral center. ♦

METHODS

Of 51 patients admitted to this EPS specialist center hospital for their first peritonectomy in the study period, 50 had a preoperative dietetic assessment, and 49 underwent upper-arm anthropometry. ♦

RESULTS

Mean body mass index (BMI) was 20.6 kg/m(2). Mean weight loss was 14% of body weight in the preceding 6 months, with 35 of 50 patients losing more than 10%. On anthropometry, 25 of 49 patients were below the 5th percentile for mid-arm circumference (MAC), 17 of 49 were below for triceps skinfold thickness (TSF), and 21 of 49 were below for mid-arm muscle circumference (MAMC). Mean handgrip strength (HGS) was 60% of normal, with 43 of 49 patients being below 85% of normal. Appetite was poor in 21 of 50 patients, and 37 of 50 had upper and 40 of 50 had lower GI symptoms. By subjective global assessment, 27 of 51 patients were graded as severely malnourished, and 5 of 51, as well-nourished. Mean serum albumin was 28 g/L and did not correlate with BMI, MAC, TSF, MAMC, or HGS. In most patients, C-reactive protein was elevated (mean: 111 mg/L). Preoperative parenteral nutrition was given to 46 of 51 patients for a mean of 21 days. ♦

DISCUSSION

Our findings demonstrate the poor nutrition status of patients admitted for EPS surgical intervention. Anthropometrics reveal depleted fat and lean body mass in EPS patients, which might be a result of anorexia and inflammation, and the reason that albumin was not an accurate marker of nutrition. Poor nutrition status is likely to negatively affect outcome in this patient group. ♦

CONCLUSIONS

Early recognition of GI symptoms may herald a diagnosis of EPS. Optimization of preoperative nutrition status with intensive nutrition support is needed.

The effect of inhibition of endoplasmic reticulum stress on lipolysis in white adipose tissue in a rat model of chronic kidney disease

AIM

Lipolysis in fat tissue plays an important role in the development of metabolic disturbances, a characteristic feature of chronic kidney disease (CKD). In the present study, we tested the hypothesis that the inhibition of endoplasmic reticulum (ER) stress could alleviate lipolysis in white adipose tissue in a rat model of CKD.

METHODS

A rat model of CKD was established by a method of reduced renal mass (RRM). Lipolysis was measured as the release of glycerol in ex vivo fat pads and cultured primary adipocytes. The activity of lipases and markers of ER stress were measured by Western blotting and immunoprecipitation.

RESULTS

Our data showed that lipolysis in visceral white adipose tissue was increased in RRM rats compared with control rats. In addition, increased phosphorylation of hormone-sensitive lipase (HSL) and binding of adipose triglyceride lipase (ATGL) to comparative gene identification-58 (CGI-58) protein were observed in the RRM rats. The phosphorylation of ER stress markers, including IRE1α, PERK, and eukaryotic initiation factor (eIF) 2α, and the expression of ER stress marker 78 kDa glucose-regulated protein (GRP78) were significantly increased in RRM rats. Treatment with an inhibitor of ER stress partially but significantly alleviated lipolysis, and this alleviation was accompanied by reduced binding of ATGL to CGI-58.

CONCLUSION

Our results showed that enhanced lipolysis and ER stress occurred in visceral white adipose tissue in a rat model of CKD. Moreover, inhibition of ER stress significantly alleviated lipolysis. These findings suggest that ER stress is a potential therapeutic target for the metabolic disturbances associated with CKD.

Effects of uremic toxin p-cresol on proliferation, apoptosis, differentiation, and glucose uptake in 3T3-L1 cells

Malnutrition is a common feature seen in chronic dialysis patients, and the survival rate of obese patients receiving such treatment is higher than that of lean patients. Irrespective of obesity or diabetes, dialysis patients commonly have insulin resistance, and the leading cause of death is cardiovascular (CV) disease. It has been reported that the concentration of p-cresol, a uremic toxin, is highly associated with CV events. As uremic toxin levels are high in dialysis patients, they may be involved in the pathogenesis of insulin resistance and CV disease in this population. However, little is known so far. Thus, we focused on this uremic toxin to examine its effects on adipocytes and their precursors. 3T3-L1 cells, a mouse preadipocyte cell line, were cultured until 90% confluency. The cells were then differentiated with 500 μM 3-isobutyl-methylxanthine, 250 nM dexamethasone, and 10 μg/mL insulin. Cell proliferation was evaluated by cell counting and bromodeoxyuridine (Brd-U) incorporation assay. Glucose uptake was estimated using radiolabeled 2-deoxyglucose. The range of concentrations of p-cresol used in the experiments was from 2 to 200 μM. The investigation of cell proliferation by cell counting revealed that, compared with control, 3T3-L1 cells treated with 100 and 200 μM p-cresol were significantly decreased in number at day 3 and day 7 of culture. The Brd-U incorporation assay also demonstrated similar inhibitory effects on cell proliferation, suggesting that p-cresol affected the normal cell cycle. Oil Red O staining at day 7 showed that the number of mature adipocytes was decreased by treatment with 200 μM p-cresol. Consistent with that finding, the number of apoptotic cells at day 7 was increased by treatment with 100 and 200 μM p-cresol. Peroxisome proliferator-activated receptor γ (PPARγ) mRNA expression increased time-dependently during the differentiation process of 3T3-L1 cells. p-Cresol dose-dependently decreased differentiation-induced mRNA expression of PPARγ. Uptake of 3H-labeled 2-deoxyglucose was markedly decreased by 200 μM p-cresol in the presence or in the absence of insulin, mainly because of the decreased number of mature adipocytes. High concentrations of p-cresol disturbed the cell cycle, induced apoptosis, inhibited the differentiation of preadipocytes into mature adipocytes, and decreased glucose uptake at baseline and after insulin stimulation. These findings indicate that accumulated p-cresol may induce reduction in adipose tissue, insulin resistance, and malnutrition, eventually leading to poor outcomes in chronic dialysis patients.

Renal transplantation: better fat than thin

BACKGROUND

Obesity has been a relative contraindication for renal transplantation. This study evaluates the impact of pretransplant body mass index (BMI) on renal transplant outcomes in a single institution in the era of modern immunosuppression.

MATERIALS AND METHODS

A 10-y retrospective analysis was undertaken of 454 consecutive patients who received a renal transplant at Westmead Hospital from January 1, 2001 to December 31, 2010. The role of pretransplant BMI on patient survival, graft survival, surgical complications, and postoperative complications was studied.

RESULTS

The mean age of transplant of this study population was 45.4 ± 13.0 y. Live donation rate was 53.5%, and 60.6% were male. The median preoperative BMI was 25.6 (range, 14.3-51.4). One-year and 5-y patient survival were 97.4% and 86.6%, respectively, whereas 1-y and 5-y death-censored graft survival were 97.1% and 91.9%, respectively. Patients with BMI >30 did not exhibit any significant difference in survival or graft failure but had higher surgical wound infection rates (hazard ratio 3.95, P < 0.01). Patients with preoperative BMI <18.5 were associated with a six-fold increase in both death and death-censored graft failure (P < 0.01).

CONCLUSIONS

Pretransplant obesity increases wound infection but is not a contraindication to renal transplantation. Future prospective studies are required to further define the impact of low preoperative BMI <18.5.

Factors associated with quality of life among hemodialysis patients in Malaysia

Although hemodialysis treatment has greatly increased the life expectancy of end stage renal disease patients, low quality of life among hemodialysis patients is frequently reported. This cross-sectional study aimed to determine the relationship between medical history, hemodialysis treatment and nutritional status with the mental and physical components of quality of life in hemodialysis patients. Respondents (n=90) were recruited from Hospital Kuala Lumpur and dialysis centres of the National Kidney Foundation of Malaysia. Data obtained included socio-demography, medical history, hemodialysis treatment and nutritional status. Mental and physical quality of life were measured using the Mental Composite Summary (MCS) and Physical Composite Summary (PCS) of the Short-Form Health Survey 36-items, a generic core of the Kidney Disease Quality of Life Short Form. Two summary measures and total SF-36 was scored as 0–100, with a higher score indicating better quality of life. Approximately 26 (30%) of respondents achieved the body mass index (24 kg/m²) and more than 80% (n=77) achieved serum albumin level (>35.0 mg/dL) recommended for hemodialysis patients. The majority of respondents did not meet the energy (n=72, 80%) and protein (n=68,75%) recommendations. The total score of SF-36 was 54.1±19.2, while the score for the mental and physical components were 45.0±8.6 and 39.6±8.6, respectively. Factors associated with a higher MCS score were absence of diabetes mellitus (p=0.000) and lower serum calcium (p=0.004), while higher blood flow (p=0.000), higher serum creatinine (p=0.000) and lower protein intake (p=0.006) were associated with a higher PCS score. To improve the overall quality of life of hemodialysis patients, a multidisciplinary intervention that includes medical, dietetic and psychosocial strategies that address factors associated with mental and physical quality of life are warranted to reduce further health complications and to improve quality of life.