Relationship between Abdominal Fat Accumulation and Insulin Resistance in Hemodialysis Patients

The Acute, Combined, and Separate Effects of Cold Hemodialysis and Intradialytic Exercise in Insulin Sensitivity and Glucose Disposal

Hemodialysis (HD) patients suffer from multiple health problems, including severe insulin resistance. Both cold dialysis and intradialytic exercise training could elicit health benefits; however, it is still unknown whether the combination of those two approaches could enhance overall health. The current study aimed to evaluate the separate and combined acute effects of a single session of cold dialysis and intradialytic exercise in parameters related to insulin sensitivity and glucose disposal. Ten HD patients (57.2 ± 14.9 years) participated in the study. Each patient participated in four different scenarios during HD: a) typical dialysis with dialysate temperature at 37°C (TD), b) cold dialysis with dialysate temperature at 35°C, c) typical HD combined with a single exercise bout, d) cold dialysis combined with a single exercise bout. Glucose disposal and insulin resistance were assessed immediately after the end of the HD session. None of the examined parameters significantly differed between the four scenarios ( p > 0.05). However, slight numerical changes and moderate to high effect size ( d : 0.50-0.85) were observed between TD versus cold dialysis and TD versus TD + exercise in glucose and insulin disposal rates. A single session of cold and TD with intradialytic exercise may provide an "acute" time-efficient stimulus for consecutively improving glucose disposal and insulin sensitivity.

Relationship between High-density Lipoprotein Cholesterol and Insulin Resistance in Non-diabetic Chronic Kidney Disease Patients

Insulin resistance is linked to cardiovascular disease (CVD), even in non-diabetic patients. Therefore, insulin resistance contributes to the development of CVDs, which are the most important cause of morbidity and mortality in chronic kidney disease (CKD) and patients receiving dialysis replacement therapy. Furthermore, CKD greatly affects the enzyme activities responsible for the metabolism of high-density lipoprotein (HDL), causing an abnormal composition and function of HDL, which results in the loss of the anti-inflammatory effect of HDL and its protective effect against CVD. The study aimed to find the relationship between HDL-C, inflammation, and insulin resistance in nondiabetic CKD patients undergoing different modalities of treatment. This prospective cross-sectional comparative study included 80 subjects divided into the control group (20 healthy participants), Group 1 (15 predialysis CKD patients on conservative treatment), Group 2 (10 peritoneal dialysis patients), and Group 3 (35 hemodialysis patients). A full history, medical examination, and a laboratory investigation were carried out on all subjects from June 2018 to June 2019. The patient groups had significantly lower HDL and higher serum insulin than the control group. HDL was negatively correlated with the Homeostatic Model Assessment of Insulin Resistance. There was a strong negative association between HDL and insulin resistance in CKD patients. Therefore, lifestyle modifications and dyslipidemia treatment in CKD might help to prevent cardiovascular events even in nondiabetic nonobese CKD patients.

Role and Treatment of Insulin Resistance in Patients with Chronic Kidney Disease: A Review

Patients with chronic kidney disease (CKD) and dialysis have higher mortality than those without, and cardiovascular disease (CVD) is the main cause of death. As CVD is caused by several mechanisms, insulin resistance plays an important role in CVD. This review summarizes the importance and mechanism of insulin resistance in CKD and discusses the current evidence regarding insulin resistance in patients with CKD and dialysis. Insulin resistance has been reported to influence endothelial dysfunction, plaque formation, hypertension, and dyslipidemia. A recent study also reported an association between insulin resistance and cognitive dysfunction, non-alcoholic fatty liver disease, polycystic ovary syndrome, and malignancy. Insulin resistance increases as renal function decrease in patients with CKD and dialysis. Several mechanisms increase insulin resistance in patients with CKD, such as chronic inflammation, oxidative stress, obesity, and mineral bone disorder. There is the possibility that insulin resistance is the potential future target of treatment in patients with CKD.

Significance of Adipose Tissue Maintenance in Patients Undergoing Hemodialysis

In the general population, obesity is known to be associated with adverse outcomes, including mortality. In contrast, high body mass index (BMI) may provide a survival advantage for hemodialysis patients, which is known as the obesity paradox. Although BMI is the most commonly used measure for the assessment of obesity, it does not distinguish between fat and lean mass. Fat mass is considered to serve as an energy reserve against a catabolic condition, while the capacity to survive starvation is also thought to be dependent on its amount. Thus, fat mass is used as a nutritional marker. For example, improvement of nutritional status by nutritional intervention or initiation of hemodialysis is associated with an increase in fat mass. Several studies have shown that higher levels of fat mass were associated with better survival in hemodialysis patients. Based on body distribution, fat mass is classified into subcutaneous and visceral fat. Visceral fat is metabolically more active and associated with metabolic abnormalities and inflammation, and it is thus considered to be a risk factor for cardiovascular disease and mortality. On the other hand, subcutaneous fat has not been consistently linked to adverse phenomena and may reflect nutritional status as a type of energy storage. Visceral and subcutaneous adipose tissues have different metabolic and inflammatory characteristics and may have opposing influences on various outcomes, including mortality. Results showing an association between increased subcutaneous fat and better survival, along with other conditions, such as cancer or cirrhosis, in hemodialysis patients have been reported. This evidence suggests that fat mass distribution (i.e., visceral fat and subcutaneous fat) plays a more important role for these beneficial effects in hemodialysis patients.

Mid-arm circumference, body fat, nutritional and inflammatory biomarkers, blood glucose, dialysis adequacy influence all-cause mortality in hemodialysis patients: A prospective cohort study

Hemodialysis patients are at the high risk for morbidity and mortality. Evaluation and management of body composition and biochemical values are important to improve dialysis outcomes. We aimed to examine the effects of the mid-arm circumference, body fat, nutritional and inflammatory biomarkers, blood glucose, and dialysis adequacy on the mortality.A prospective cohort study was conducted on 375 patients from 7 hospital-based dialysis centers. At baseline between September 2013 and April 2017, we assessed patients' characteristics using chart review, body composition using the bioelectrical impedance analysis, and biochemical parameters using available laboratory tests. Patients were followed-up for all-cause mortality until April 2018. Kaplan-Meier Curves with Log-rank test, and Cox proportional hazards models were used to analyze the effects of assessed factors on the mortality.During the median of follow-up time of 1.4 (1.0-3.2) years, 47 (12.5%) patients died. In the multivariate analysis, mid-arm circumference (hazard ratio, HR, 0.90; 95% confidence interval, 95%CI, 0.82-0.99; P = .036), body fat mass (HR, 0.95; 95%CI, 0.91-1.00; P = .031), percent body fat (HR, 0.96; 95%CI, 0.92-0.99; P = .024), serum creatinine (HR, 0.81; 95%CI, 0.68-0.96; P = .015), and eKt/V (HR, 0.07; 95%CI, 0.01-0.33; P = .001) reduced the mortality risk. Inflammation (HR, 2.90; 95%CI, 1.59-5.27; P < .001), hyperglycemia (HR, 2.16; 95%CI, 1.06-4.40; P = .033), and low serum uric acid (HR, 2.22; 95%CI, 1.15-4.31; P = .018) increased the death risk.In hemodialysis patients, the higher values of the mid-arm circumference, body fat, serum creatinine, uric acid, and dialysis adequacy were associated with lower mortality, whereas, inflammation and hyperglycemia associated with higher mortality.

Abdominal obesity in normal weight versus overweight and obese hemodialysis patients: Associations with nutrition, inflammation, muscle strength, and quality of life

OBJECTIVE

The biological basis of abdominal obesity leading to more severe outcomes in patients with normal body mass index (BMI) on maintenance hemodialysis (MHD) is unclear. The aim of this study was to compare the properties of abdominal obesity in different BMI categories of patients on MHD.

METHODS

We performed a cross-sectional study of 188 MHD patients (52.7% women; mean age, 69.4 ± 11.5 y) with abdominal obesity in different BMI groups using criteria from the World Health Organization. Appetite and dietary intake, body composition, handgrip strength, malnutrition inflammation score (MIS), inflammatory biomarkers, adipokines, and health-related quality-of-life (QoL) questionnaires were studied.

RESULTS

According to multivariable analyses, abdominally obese patients with normal BMIs consumed less protein per day (P = 0.04); had lower measurements of surrogates of lean (P < 0.001) and fat mass (P < 0.001); and had higher total cholesterol, tumor necrosis factor-α (P < 0.05), and ratios of adiponectin to leptin (P = 0.003) than overweight and obese patients with abdominal obesity. Multivariable analyses showed no differences in handgrip strength among the study groups.The abdominally obese study participants with normal weight had significantly lower scores in role physical (P = 0.003) and pain (P = 0.04) scales after multivariable adjustments.

CONCLUSIONS

Normal-weight MHD patients with abdominal obesity exhibited a more proatherogenic profile in terms of inflammatory markers and adipokine expression, lower body composition reserves, and lower physical ability than patients with abdominal obesity with overweight and obesity. This at least partially explains the abdominal obesity paradox in the MHD population in which worse clinical outcomes are seen in abdominally obese patients with normal BMIs, as opposed to overweight and obese patients who are also abdominally obese.

Waist circumference as a predictor of mortality in peritoneal dialysis patients: a follow-up study of 48 months

Body-fat gain is a common finding among peritoneal dialysis (PD) patients, and the accumulation of adipose tissue occurs predominantly in the abdominal area. Waist circumference (WC) is a reliable marker of abdominal obesity and its association with worse outcomes has been demonstrated in non-dialysis and haemodialysis patients. We aimed at investigating whether WC measurements as well as the changes over time in WC were able to predict mortality in PD patients. This prospective study included 109 patients undergoing PD (57 % male, age 52 (sd 16) years, 32 % diabetics, 48 % BMI≥25 kg/m2). WC was measured at the umbilicus level (empty abdominal cavity), and values >88 cm for women and >102 cm for men were considered high. Nutritional status and laboratory parameters were also evaluated. WC was measured at baseline and after 6 months, and mortality was registered during a period of 48 months. High WC was observed in 55 % of women and in 23 % of men at baseline. After 6 months, 61 % of the patients showed an increased WC. At the end of the study, twenty-seven deaths were registered. A significant increase in WC was observed only in the non-survivor group. In the Cox regression analysis adjusting for sex, age, duration on dialysis, diabetes, BMI, serum albumin and C-reactive protein, high WC at baseline as well as the 6-month increase in WC were independently associated with mortality. This study demonstrated that a high WC and the increase over time in WC were both predictors of mortality in PD patients.

Central obesity and risks of cardiovascular events and mortality in prevalent hemodialysis patients

BACKGROUND

To date, no attempt has been made to assess the best anthropometric method for defining abdominal adiposity in hemodialysis (HD) patients or to determine whether the quantity of intra-abdominal fat relates to morbidity and mortality in that population. We aimed to describe the prevalence of central obesity in HD patients and to investigate the relationship between central obesity assessed by anthropometric variables, and composite outcomes, cardiovascular morbidity and mortality among HD patients and whether this parameter correlates with intra-abdominal fat assessed by computed tomography scan (CT scan).

METHODS

The procedures followed were in accord with the ethical standards of the committee on human experimentation of our institution. Informed oral consent was obtained from all patients. This was a cross-sectional study of 120 prevalent HD patients. Anthropometric measurements including body mass index, conicity index (Ci), waist-hip ratio (WHR), waist circumference (WC), waist-to-height ratio (WHtR), and visceral adiposity index (VAI) were recorded. Visceral and subcutaneous abdominal fat were assessed by CT scan. Comorbidity was scored for both the Charlson comorbidity index (CCI) and Davies comorbidity index.

RESULTS

Twenty-eight patients (23.3%) were centrally obese based on anthropometry. By linear regression analysis, Ci, WHR, and VAI were predictors of CT assessed central obesity; p 0.042, 0.001, and 0.010, respectively. On assessment of the relationship between the abdominal obesity and the comorbidity indices, there was a positive significant correlation between Ci and CCI (p 0.025) and Davies score (p 0.002) which are predictors of mortality. During the mean follow-up period (3.2 years), 56 patients reached the composite outcome; eight patients died and 48 experienced CV events. Central obesity measured by anthropometry was a predictor of composite outcomes, cardiovascular morbidity, and mortality in HD patients by regression analysis and cox regression model. Only WC and WHtR did not predict mortality.

CONCLUSION

Ci, WHR, and VAI are cheap alternatives for accurate assessment of morbidity and mortality risk in centrally obese prevalent HD patients.

Protein Nutrition and Malnutrition in CKD and ESRD

Elevated protein catabolism and protein malnutrition are common in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). The underlying etiology includes, but is not limited to, metabolic acidosis intestinal dysbiosis; systemic inflammation with activation of complements, endothelin-1 and renin-angiotensin-aldosterone (RAAS) axis; anabolic hormone resistance; energy expenditure elevation; and uremic toxin accumulation. All of these derangements can further worsen kidney function, leading to poor patient outcomes. Many of these CKD-related derangements can be prevented and substantially reversed, representing an area of great potential to improve CKD and ESRD care. This review integrates known information and recent advances in the area of protein nutrition and malnutrition in CKD and ESRD. Management recommendations are summarized. Thorough understanding the pathogenesis and etiology of protein malnutrition in CKD and ESRD patients will undoubtedly facilitate the design and development of more effective strategies to optimize protein nutrition and improve outcomes.

Liver fat contents, abdominal adiposity and insulin resistance in non-diabetic prevalent hemodialysis patients

BACKGROUND

The liver fat contents and abdominal adiposity correlate well with insulin resistance (IR) in the general population. However, the relationship between liver fat content, abdominal adiposity and IR in non-diabetic hemodialysis (HD) patients remains unclear. This study aimed to clarify the associations among these factors.

METHODS

This is a cross-sectional, observational study. All patients received abdominal ultrasound for liver fat content. Abdominal adiposity was quantified with the conicity index (Ci) and waist circumference (WC). We checked the homeostasis model assessment for insulin resistance index (HOMA-IR) for IR.

RESULTS

A total of 112 patients (60 women) were analyzed. Subjects with higher liver fat contents and WC had higher IR indices. But Ci did not correlate with IR indices. In both the multi-variable linear regression model and the logistic regression model, only higher liver fat content predicted a severe IR status.

CONCLUSIONS

Liver fat contents have a remarkable correlation with IR; however, abdominal adiposity, measured either by Ci or WC, dose not independently correlate with IR in non-diabetic prevalent HD patients.

Cats differ from other species in their cytokine and antioxidant enzyme response when developing obesity

OBJECTIVES

Obese cats show many similarities to obese people, including insulin resistance and an increased diabetes risk. However, atherosclerosis and cardiovascular disease are not seen in cats. In people, they are associated with the development of an inflammatory response, which, we hypothesized, does not occur in cats.

DESIGN AND METHODS

Twenty neutered cats of equal gender distribution were allowed to gain weight by offering food ad libitum and were examined before and at 10, 30, 60, and 100% weight gain. All cats reached 60% of weight gain, 12 cats gained 100% in 12 months.

RESULTS

Fat was equally distributed between subcutaneous and visceral depots. Insulin-independent glucose uptake increased and insulin sensitivity decreased with increasing adiposity. However, baseline glucose concentrations were unchanged suggesting a decrease in EGP. Inflammatory cytokines (Il-1, IL-6, TNFa) and catalase, superoxide dismutase, glutathione peroxidase did not change. Insulin, proinsulin, and leptin were positively and adiponectin negatively correlated with adiposity. Heat production increased with obesity, but became less when body weight gain was > 60%.

CONCLUSIONS

This indicates that metabolism adapts more appropriately to the higher intake of calories in the initial phase of obesity but slows at higher body fat content. This likely contributes to the difficulty to lose weight.

Visceral obesity assessed by computed tomography predicts cardiovascular events in chronic kidney disease patients

BACKGROUND AND AIM

Cardiovascular disease is the leading cause of death among patients with chronic kidney disease (CKD). Although there is emerging evidence that excess visceral fat is associated with a cluster of cardiometabolic abnormalities in these patients, the impact of visceral obesity evaluated by a gold-standard method on future outcomes has not been studied. We aimed to investigate whether visceral obesity assessed by computed tomography was able to predict cardiovascular events in CKD patients.

METHODS AND RESULTS

We studied 113 nondialyzed CKD patients [60% men; 31% diabetics; age 55.3 ± 11.3 years; body mass index (BMI) 27.2 ± 5.3 kg/m(2); estimated glomerular filtration rate (GFR) 33.7 ± 13.6 ml/min/1.73 m(2)]. Visceral and subcutaneous abdominal fat were assessed by computed tomography at L4-L5. Visceral to subcutaneous fat ratio >0.55 (highest tertile cut-off) was defined as visceral obesity. Cardiovascular events including acute myocardial infarction, angina, arrhythmia, uncontrolled blood pressure, stroke and cardiac failure were recorded during 24 months. Cardiovascular events were 3-fold higher in patients with visceral obesity than in those without visceral obesity. The Kaplan-Meier analysis indicated that patients with visceral obesity had shorter cardiovascular event-free time than those without visceral obesity (P = 0.021). In the univariate Cox analysis, visceral obesity was associated with higher risk of cardiovascular events (hazard ratio = 3.4; 95% confidence interval = 1.1-10.5; P = 0.03). The prognostic power of visceral obesity for cardiovascular events remained significant after adjustments for sex, age, diabetes, previous cardiovascular disease, smoking, sedentary lifestyle, BMI, GFR, hypertension, dyslipidemia and inflammation.

CONCLUSION

Visceral obesity assessed by computed tomography was a predictor of cardiovascular events in CKD patients.

Visceral fat and coronary artery calcification in patients with chronic kidney disease

BACKGROUND

Abdominal fat is a metabolically active tissue which has been associated with cardiovascular events and death in chronic kidney disease (CKD) patients. We explore here the association between surrogates of abdominal fat and coronary artery calcium score (CACs).

METHODS

Cross-sectional analysis of 232 non-dialysis-dependent CKD patients Stages 3-5 (median age 60 [25th-75th percentile 52-67] years; 60% men). Visceral adipose tissue (VAT) and CACs were assessed by computed tomography. Surrogates of abdominal fat included VAT and waist circumference (WC).

RESULTS

VAT was positively associated with CACs in univariate analysis (ρ = 0.23). Across increasing VAT quartiles, patients were older, more often men and smokers. Although increasing VAT quartiles associated with higher glomerular filtration rate and leptin, better nutritional status (subjective global assessment) as well as larger muscle stores and strength, they were also more insulin resistant (HOMA-IR), dyslipidemic and inflamed (C-reactive protein and white blood cells). In addition, CACs were incrementally higher. Clinically evident coronary artery calcification (CACs ≥ 10 Agatston) was present in 63% of the patients. Both increased visceral fat (odd ratio 1.60 [95% CI 1.23-2.09] per standard deviation increase) and increased WC (1.05 [1.01-1.12] per cm increase), augmented the odds to present calcification. Such associations remained statistically significant after extensive multivariate adjustment for confounders.

CONCLUSIONS

Abdominal fat is associated with coronary artery calcification in non-dialysis dependent CKD patients, supporting its potential role as a cardiovascular risk factor in uremia.

Zinc-α2-glycoprotein: is there association between this new adipokine and body composition in hemodialysis patients?

Peptides involved in the regulation of body composition are of interest in hemodialysis (HD) patients because protein wasting associated with high fat mass (FM) is present in these patients. Zinc-α2-glycoprotein (ZAG), a new adipokine, is involved in the regulation of lipid metabolism, adiposity, and energy balance. The purpose of this study was to evaluate ZAG levels and its relationship with body composition and dietary intake in HD patients. Forty-nine HD patients (28 men, 53.1 ± 12.5 years, and BMI 24.0 ± 4.3 kg/m2) were studied and compared with 20 healthy subjects (9 men, 49.5 ± 15.2 years, and BMI 25.6 ± 4.1 kg/m(2)). Plasma ZAG levels were measured using the ELISA methods and body composition was evaluated through anthropometric data. Dietary intake was assessed 3 days by 24-hour food recall. Although most of the HD patients (59.2%) were eutrophic according to BMI, 92.3% presented high percentage of body fat (BF), and 43.5%, reduced fat-free mass according to midarm muscle circumference values. ZAG levels were ∼2.5-fold higher in HD patients (135.9 ± 40.9 mg/L) compared with healthy individuals (54.6 ± 23.0 mg/L) (p < 0.0001). Circulating ZAG was not associated with dietary intake; however, this peptide was negatively correlated with %BF and, for each 1% reduction in BF, ZAG levels increased by 2.4 mg/L (p = 0.02). In summary, circulating ZAG is increased and inversely correlated with adiposity in HD patients; however, in spite of its higher plasma levels, the majority of HD patients did not show low BF.

Relationship between fat mass and serum high-sensitivity C-reactive protein levels in prevalent hemodialysis patients

BACKGROUND/AIMS

Little is known about the relationship between fat mass distribution and chronic inflammation in dialysis patients, in whom chronic inflammation is related to morbidity and mortality.

METHODS

The fat and lean masses (truncal and nontruncal) of 452 hemodialysis patients (age: 64 ± 11 years; hemodialysis duration: 89 ± 77 months; 37% diabetics) were measured by dual X-ray absorptiometry and their association with high-sensitivity C-reactive protein (hsCRP) was examined.

RESULTS

The fat mass of the high hsCRP group (n = 106) was significantly higher than that of the normal hsCRP group (n = 346; p < 0.05); there were no significant differences in lean mass between the two groups. Truncal fat mass of the former group was significantly greater than that of the latter (p < 0.05), but there was no significant difference in nontruncal fat mass between the two groups. In multiple regression analysis, truncal fat mass (β = 0.227, p < 0.01) was significantly and independently associated with serum hsCRP levels after adjustment for age, gender and serum albumin (R(2) = 0.137, p < 0.01), whereas nontruncal fat mass was not.

CONCLUSION

Fat mass, particularly truncal fat mass, but not lean body mass, was significantly associated with serum hsCRP levels. The results suggest that truncal fat mass exhibits a distinct effect on chronic inflammation in hemodialysis patients.

Association of conicity index and renal progression in pre-dialysis chronic kidney disease

BACKGROUND/OBJECTIVES

Abdominal fat deposition is represented by means of the conicity index (CI), an anthropometric estimate that models the relative accumulation of abdominal fat. We examined the influence of markers of cardiovascular disease in terms of inflammation and lipid profile and body fat distribution on the progression of renal disease in patients with stable chronic kidney disease (CKD) stages 3-5.

MATERIAL AND METHODS

We studied 104 pre-dialysis CKD patients (64 males, 62%; age 64.6 ± 14.7 years). Glomerular filtration rate (GFR) was estimated (44.62 ± 14.38 mL/min/1.73 m2) by modification of diet in renal disease formula. GFR values were estimated at baseline and at the end of the 12-month follow-up. Patients were stratified into three groups: group 1 had a loss of GFR ≥20%; group 2 had a loss of GFR 10-20%; and group 3 patients had stable renal functions or GFR change <10% at the end of 12 months. Body mass index (BMI), waist/hip ratio (WHR), and CI were subsequently computed. Renal resistive index (RRI) was measured using Doppler ultrasonography.

RESULTS

CI was strongly correlated with total cholesterol (r = 0.37, p < 0.01), low-density lipoprotein (LDL) (r = 0.53, p < 0.01), C-reactive protein (r = 0.21, p < 0.05), and serum potassium (r = 0.216, p < 0.02), whereas BMI and WHR were not associated with these parameters. The values of CI, serum cholesterol, LDL, alkaline phosphatase, alanine aminotransferase, lactate dehydrogenase activity, the degree of proteinuria and microalbuminuria, and RRI were significantly lower in group 3. In linear regression model, LDL (r2 = 0.17, p = 0.02), uric acid (r2 = 0.19, p < 0.01), and RRI (r2 = 0.64, p < 0.01) were independently associated with CI for all groups.

CONCLUSION

CI is an independent predictor of systemic inflammation, cardiovascular risk, and GFR in patients during the pre-dialysis period.

Decreased high-density lipoprotein cholesterol is associated with inflammation and insulin resistance in non-diabetic haemodialysis patients

AIM

Lower serum high-density lipoprotein cholesterol (HDL-C) is associated with inflammation, insulin resistance and poor cardiovascular outcomes in the general population. However, in a large-scale study, the association between HDL and survival in haemodialysis patients was not present. The exact cause of lack of HDL-C protection in the dialysis population is still obscure.

METHODS

A total of 89 stable non-diabetic haemodialysis patients were recruited. Fasting serum biochemical parameters, complete blood counts and inflammatory markers were obtained before the mid-week dialysis. Insulin resistance was assessed by the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR).

RESULTS

The mean age was 58.2±13.1 years, 37 (41.6%) patients were male. The mean HDL-C level was 56.3±17.1 mg/dL. By bivariate correlation analysis, a lower serum HDL-C level was related to higher body mass index (r=-0.425; P<0.001), higher triglyceride (r=-0.479; P<0.001) and higher HOMA-IR (r=-0.211; P<0.05) levels. The serum HDL-C level was also inversely related to high-sensitivity C-reactive protein (hsCRP) (r=-0.297; P=0.005) and tumour necrosis factor-α (TNF-α) (r=-0.295; P=0.005) and directly correlated with adiponectin (r=0.560; P<0.001). In multivariate linear regression analysis, HDL-C was found to be directly correlated with adiponectin (β-coefficient=0.569; P<0.001) and inversely correlated with TNF-α (β-coefficient=-0.292; P=0.001).

CONCLUSION

A strong association between HDL-C, inflammatory surrogates, and insulin resistance in this non-diabetic, non-obese haemodialysis patient group is demonstrated. The HDL-C level is still a good parameter to screen high-risk patients.

Adiposity and insulin resistance in nondiabetic hemodialysis patients: effects of high energy supplementation

BACKGROUND

In contrast to the general population, a higher body mass index is associated with better survival among hemodialysis patients. Theoretically, high energy supplementation in these patients ought to lead to weight gain over time, but the benefits of this strategy are unclear.

OBJECTIVE

The objective was to assess whether high energy supplementation in nondiabetic hemodialysis patients might adversely affect insulin resistance -- a known risk factor for cardiovascular disease.

DESIGN

We first investigated the association between body fat mass and insulin resistance (homeostasis model assessment of insulin resistance; HOMA-IR) in nondiabetic hemodialysis patients in a cross-sectional analysis (study 1). Of the 106 individuals studied, 55 were randomly assigned to either high energy supplementation (an extra 475 kcal/d; n = 28) or not (n = 27) for 12 wk to assess prospective changes in body fat mass and insulin resistance (study 2).

RESULTS

In study 1, body fat mass (P < 0.05) and C-reactive protein (CRP) (P < 0.05) each contributed independently to HOMA-IR. In study 2, 41 patients completed the study. The 20 patients who received high energy supplementation had a significantly greater increase in body fat mass (P < 0.05), CRP (P < 0.05), and HOMA-IR (P < 0.001) than did the 21 controls.

CONCLUSIONS

Body fat mass and CRP are primary determinants of insulin resistance in nondiabetic hemodialysis patients. High energy supplementation, because it increases adiposity and inflammation, exacerbates insulin resistance. A long-term study is needed to clarify the metabolic effects of high energy supplementation on cardiovascular disease outcomes in hemodialysis patients.