Does body fat mass define survival in patients starting peritoneal dialysis?

Association analysis of body composition with survival among prevalent peritoneal dialysis patients

PURPOSE

Progressive decline in lean mass and gain of fat mass are common in patients treated with peritoneal dialysis (PD). It is unclear whether body composition or its longitudinal changes contribute to increased mortality among prevalent PD patients.

METHODS

This was a retrospective cohort study. Body composition was assessed using bioelectrical impedance spectroscopy (BIS). Lean and fat tissue indices were derived from lean and fat mass indexed to height-squared, respectively. The patient's baseline BIS results were used to explore its mortality risk prediction for the entire cohort. Among patients with subsequent BIS measurements, changes of lean and fat mass over time were also examined with survival outcomes.

RESULTS

Among all participants (n = 555, PD vintage 38 months), higher baseline lean tissue index was associated with lower mortality after adjusting for fat tissue index and confounders (HR 0.90; 95% CI 0.84-0.97, p = 0.01). However, this association was no longer significance after the final adjustment with serum albumin level (p = 0.06). A total of 136 patients had repeated BIS data. After the interval of 10.1 months during two consecutive BIS measurements, there was a strong inverse correlation between the percentage changes of lean and fat tissue indices (r = - 0.73, p < 0.001). The longitudinal changes in lean mass, either high or low categories, were not significantly associated with all-cause mortality. In contrast, patients who were classified as having low values of fat tissue index (below median) from baseline to the next BIS measurements had a lower odds of death in the univariable (HR 0.32; 95% CI 0.12-0.84, p = 0.02) but not in the adjusted models.

CONCLUSION

Among prevalent PD patients, higher baseline lean mass was independently associated with better survival. However, the longitudinal changes in lean mass were not significantly associated with mortality. In contrast, the maintenance of low fat status over time appeared to be associated with a lower likelihood of death among PD population.

Prevalence and risk factors of exit-site infection in incident peritoneal dialysis patients

BACKGROUND

Exit-site infection (ESI) is a common complication in peritoneal dialysis (PD) patients. Clearly understanding the risk factors may be useful for the prevention of ESI. This study was to explore the prevalence and risk factors of ESI in incident PD patients.

METHODS

We evaluated ESI in incident PD patients who had catheter insertion in our center between 1 January 2009 and 31 December 2013, with follow-up for 1 year. We collected data on demographics, clinical features, and nursing care methods of the exit site (ES).

RESULTS

We recruited 1133 incident PD patients (687 male (60.6%); mean age 47.0 ± 15.1 years), and 245 (21.6%) had diabetes. Median follow-up was 12.0 months. One hundred and thirty-one patients had 139 episodes of ESI with a rate of 92.8 patient-months per episode (0.13 episodes per year). Coagulase-negative staphylococcus was the main pathogen, accounting for 33.8% of the ESIs. Gram-positive rods, Staphylococcus aureus, Pseudomonas, fungi, and other organisms accounted for 23.0%, 15.8%, 1.4%, 1.4%, and 2.9%, respectively. No bacterial growth was found in 15.1%. There were no differences in demographic and laboratory data (age, gender, primary kidney disease, hemoglobin, white blood cell, serum albumin, blood urea nitrogen, serum creatinine, and C-reactive protein) between the ESI and non-ESI groups. Poor competency of ES care, poor catheter immobilization, history of catheter-pulling injury, and mechanical stress on the ES were significantly associated with increased risk of ESI.

CONCLUSIONS

The prevalence of ESI was 0.13 episodes per year. Poor competency of ES care, catheter mobilization, history of catheter-pulling injury, and mechanical stress by waist belt or the protective bag of PD on ES were risk factors for ESI.

Effect of Long-term Peritoneal Dialysis on Change in Visceral Fat Area: A Single-Center Experience

INTRODUCTION

Visceral fat area (VFA) is known to increase after initiation of peritoneal dialysis (PD). However, the factors contributing to the increase in VFA in long-term PD patients have not been sufficiently elucidated. The present study investigated factors that affect VFA in patients who continue PD for ≥3 years.

METHODS

Twenty patients (63.1 ± 10.3 years, 9 men, 11 diabetic patients) between January 2008 and January 2015 were included. VFA, subcutaneous fat area (SFA) and waist circumference at initiation and follow-up were measured at the level of the umbilicus by computed tomography using an image analysis system. Change in VFA was defined as the value obtained by dividing VFA at the final follow-up by that at the initiation. The correlations between clinical parameters at initiation and changes in VFA were analyzed.

RESULTS

There was no significant change in body weight (57.6 ± 10.4 vs 58.3 ± 7.8 kg, P = 0.296) during the mean final follow-up period of 55 ± 13 months, although VFA increased significantly (103.6 ± 39.2 vs 122.6 ± 38.3 cm2, P = 0.030). Although subcutaneous fat area (SFA) did not change (124.7 ± 52.3 vs 124.5 ± 49.2 cm2, P = 0.989), waist circumference increased significantly (79.4 ± 8.4 vs 83.7 ± 6.9 cm, P = 0.010). SFA (r = -0.735, P < 0.001), waist circumference (r = - 0.644, P = 0.002), high-density lipoprotein cholesterol (HDL-C) (r = 0.487, P = 0.029), and age (r = 0.507, P = 0.023) correlated significantly with changes in VFA.

CONCLUSIONS

VFA might increase with long-term PD in patients with end-stage kidney disease who have high HDL-C, small SFA, and small waist circumference at initiation.

Clinical value of body composition monitor to evaluate lean and fat tissue mass in peritoneal dialysis

BACKGROUND/OBJECTIVES

Bioimpedance analysis is often routinely performed in any dialysis unit to guide fluid management but can provide a reproduceable assessment of fat and muscle mass. We wished to determine the clinical significance of low muscle or high fat mass and the determinants that influence their change.

SUBJECTS/METHODS

We performed retrospective analysis of 824 patients on peritoneal dialysis who underwent routine repeated bioimpedance analysis measurements using the body composition monitor (BCM).

RESULTS

Lean tissue index (LTI) was an independent predictor of mortality when sex, age, PD vintage and diabetes status were included in the models (HR 0.93; 95% CI 0.86-1.00, p < 0.05) and when baseline serum albumin was included in a separate model (HR 0.86; 95% CI: 0.79-0.93, p < 0.001). High fat tissue index (FTI) was an independent predictor of mortality when demographic factors were included (HR 0.87; 95% CI: 0.78-0.97, p < 0.02), but not with the addition biochemical parameters. Changes in body composition of 206 patients over a 2-year follow-up period could not be predicted by baseline demographics, functional or biochemical assessments. However, there was a strong inverse relationship between changes in LTI and FTI. There were no associations between changes in body composition with prescribed dialysate glucose.

CONCLUSIONS

We showed body composition changes are common and complex. LTI was an independent predictor of survival. Changes in LTI and FTI could not be predicted by baseline parameters. BCM may be a sensitive and accurate tool to monitor changes in body composition during dialysis treatment.

Hydration and nutritional status in patients on home-dialysis-A single centre study

BACKGROUND

Over-hydration (OH) and malnutrition are prevalent among patients on dialysis therapy. The prevalence of OH and malnutrition as well as the risk factors associated with OH and malnutrition in our patients on home peritoneal dialysis (PD) and home haemodialysis (HD) are examined.

DESIGN AND METHODS

This was a cross-sectional study. The hydration and nutritional status of the study groups were assessed by a Body Composition Monitor. Patients who were stable on home dialysis therapy for over one year were invited to participate. Univariate and multivariate analyses were performed to identify associated factors and determine the predictors of OH and malnutrition, respectively.

RESULTS

Eighty-eight patients (41 PD and 47 home HD) were recruited. A 32.95% of our patients on home dialysis therapy were in OH status. There was a significance difference in the prevalence of hydration status between patients on PD and home HD (p = 0.014), as overhydration was more common in patients on PD than home HD (46.34 vs. 21.28%). Dehydration was more common in patients on home HD than PD (29.79 vs. 9.76%). Male gender, decreasing haemoglobin level and presence of diabetes mellitus (DM) were risk factors of OH on multivariable analysis. There was no significance difference in the prevalence of malnutrition between patients on PD and home HD (p = 0.27). Increasing Fat Tissue Index (FTI), height and patients on PD therapy were at higher risk of malnutrition.

CONCLUSION

OH and malnutrition were prevalent patients on home dialysis therapy.

Clinical features of patients treated by peritoneal dialysis for over a decade

BACKGROUND

Peritoneal dialysis (PD) is well-established as renal replacement therapy in end stage renal disease and has survival rates similar or better than hemodialysis (HD) for the initial years on dialysis therapy. However retention rate is lower due to higher technique failure rates than in HD and few patients stay on PD for more than 10 years (PD_{>10 yrs}). Here we investigated clinical features characterizing PD_{>10 yrs} patients.

PATIENTS AND METHODS

In a single center study of 450 prevalent PD patients, 35 PD_{>10 yrs} patients (n=35) were compared with patients (n=415) who had been on PD for shorter periods of time in terms of clinical characteristics. Peritoneal transport, blood pressure, solute clearance, nutrition status, and blood calcium, phosphate and parathyroid hormone levels were measured dialysis start and, in PD_{>10 yrs} patients, also after 5 and 10 years of PD.

RESULTS

The PD_{>10 yrs} patients differed from the other PD patients in that (1) the proportion of women was higher; (2) body mass index (BMI) was lower; (3) there was no patient with diabetic nephropathy as primary diagnosis; (4) the incidence of peritonitis was lower; (5) glomerular filtration rate was higher; and (6) parathyroid hormone (PTH) levels were lower in those with decade-long PD treatment. In PD_{>10 yrs} patients, serum albumin was maintained at a high level throughout the 10 year follow up; hemoglobin levels after 5 and 10 years of PD were higher than at the beginning of the treatment; blood calcium and phosphate concentrations were maintained at acceptable levels; while the dialysate/plasma ratio of creatinine, D/P-value, increased during the decade-long PD treatment.

CONCLUSIONS

Patients receiving PD_{>10 years} had lower incidence of peritonitis, lower BMI, adequate control of blood calcium and phosphate levels and solute clearance, and were more often women than PD patients treated for shorter periods of time.

The Relationship Between Body Composition and Bone Quality Measured with HR-pQCT in Peritoneal Dialysis Patients

BACKGROUND

Bone is known to be impaired in chronic kidney disease and dialysis patients. Recent studies have shown that body composition (fat mass and lean mass) may impact bone health. Some of these effects may be related to mediators that are secreted by adipose tissue.

METHODS

The aim of this study was to evaluate the association between body composition (dual x-ray absorptiometry [DEXA]) and adipokines (leptin, adiponectin), with bone density and microarchitecture assessed with high-resolution peripheral quantitative computed tomography (HR-pQCT) in chronic peritoneal dialysis (PD) patients in a single-center prospective study.

RESULTS

Twenty-three patients with a median age of 61 years and body mass index (BMI) of 27 kg/m² were recruited. On univariate analysis, age was negatively associated with total volumetric bone mineral density (vBMD) (r = -0.75, p < 0.01), cortical vBMD (r = -0.85, p < 0.01), and cortical thickness (r = -0.71, p < 0.01). There was a negative association between leptin and cortical thickness (r = -0.48, p = 0.021). Fat mass (FM) was negatively correlated with cortical thickness (r = -0.52, p = 0.012). No association was found between bone parameters and dialysis duration, serum insulin, intact parathyroid hormone, osteocalcin, and adiponectin. The short dialysis vintage could in part explain the lack of correlation with bone parameters. In multivariate analysis, FM was significantly and negatively correlated with total vBMD, cortical and trabecular thickness.

CONCLUSIONS

These data suggest that FM is negatively associated with bone quality in PD patients, supporting a relation between body composition and bone that is independent from other dialysis-associated complications. The relative contribution of the different fat deposits (visceral versus subcutaneous) needs to be assessed in future studies.

The 24-Month Changes in Body Fat Mass and Adipokines in Patients Starting Peritoneal Dialysis

♦ BACKGROUND: Peritoneal dialysis (PD) is characterized by a gain in fat mass. The fat tissue is a complex endocrine organ that releases various adipokines. In this study, we prospectively examined serial changes of fat composition and adipokines in patients undergoing PD. ♦ METHODS: Body composition was assessed by computed tomography (CT). Nutrition status and adipokines (leptin, adiponectin, interleukin [IL]-6, and tumor necrosis factor [TNF]-α) were assessed on the 7th day and 6 months, 12 months, and 24 months after the start of PD. ♦ RESULTS: Fifty-four patients (28 men), with a mean age of 53.2 ± 13.2 years, were enrolled. Baseline fat mass, especially subcutaneous fat mass, was correlated with baseline leptin (ρ = 0.612), adiponetin (ρ = -0.477), and interleukin-6 (IL-6) (ρ = 0.391). Visceral fat mass was correlated with leptin (ρ = 0.545) and adiponectin (ρ = -0.514). Baseline adiponectin was negatively correlated with baseline leptin (ρ = -0.363). While body weight and leptin increased during the 24 months, serum adiponectin decreased in that period. The changes in visceral and subcutaneous fat mass were greater in the first 12 months and 6 months, respectively. There was no difference in IL-6 and TNF-α. Eight patients died during the follow-up period (mean 47.4 months). Twenty-seven patients continued PD. Increased baseline and serial change of IL-6 level were risk factors for mortality. After adjusting for age, sex, diabetes mellitus (DM), and coronary vascular disease (CVD), the significance of the IL-6 level disappeared. ♦ CONCLUSIONS: Baseline subcutaneous fat in patients starting PD is correlated with baseline adipokine levels rather than visceral fat. The increase in subcutaneous fat was greatest in the first 6 months. While leptin and adiponectin increased and decreased respectively, IL-6 did not change in the first 24 months.

Metabolic syndrome and obesity in peritoneal dialysis

Metabolic syndrome (MS) refers to clustering of features related to increased risk of cardiovascular disease, which include obesity or central obesity, dyslipidemia, diabetes mellitus or insulin resistance, together with hypertension. The prevalence of MS in end-stage renal failure patients on peritoneal dialysis is quite common, ranging from 40% to 60%, depending on the population studied and the definition used. However, there are controversies about the clinical outcome of patients with MS, particularly in the area of obesity. Whether peritoneal dialysis predisposes patients to MS is another unsolved issue. Despite these controversies, preventing patients from developing MS is important, at least from a theoretical point of view.

Abdominal Obesity and Mortality in Continuous Ambulatory Peritoneal Dialysis Patients

Background

The relationship between abdominal obesity (AO) and mortality in peritoneal dialysis (PD) patients is controversial.

Methods

The prevalence of AO in 84 PD patients was assessed in a cross-section manner and followed up for 9 years at a single center. AO was defined as a waist circumference (WC) of more than 90 cm in males or more than 80 cm in females. The patients were classified as either with AO(AO group) or without AO(nAO group).

Results

The AO group was older, contained more diabetics, more females, and had higher Charlson comorbidity index (aCCI) scores, BMI, and triglyceride and lower serum creatinine than the non-AO subjects. The follow-up duration was 53.2±34.4 months. At the end of the follow-up, eighteen patients (21.4%) were dead; 9 died of cardiovascular causes. The five year survival rate was 40.8%. Kaplan-Meier analysis revealed that both all-cause and cardiovascular-cause mortalities were similar in the AO and nAO groups. Multivariate analysis revealed the presence of AO not to be an independent risk factor of all-cause and cardiovascular-cause mortality.

Conclusion

AO itself might not be a risk factor for mortality in PD patients. Nevertheless, further prospective studies with a large number of patients will be needed to prove this.

Left ventricular diastolic dysfunction in peritoneal dialysis: a forgotten risk factor

Left ventricular diastolic dysfunction (LVDD) is common among patients undergoing peritoneal dialysis (PD). We examined the relationship between LVDD, major adverse cardiovascular events (MACE), and mortality in PD patients. A total of 149 patients undergoing PD with preserved left ventricular systolic function were included and followed for 3.5 years. LVDD was diagnosed (according to the European Society of Cardiology guidelines) by conventional and tissue Doppler echocardiography. Serum high-sensitivity C-reactive protein (hsCRP) was measured. The location and volume of adipose tissue were assessed by computed tomography (CT) at the level of the fourth lumbar vertebra. Subjects with LVDD had higher levels of hsCRP, and more visceral and peritoneal fat than controls. The relationship between adjusted visceral adipose tissue and LVDD became nonsignificant when hsCRP and baseline demographic data were introduced into the logistic regression model (odds ratio = 1.52, P = 0.07). Subsequent hierarchical multivariate Cox regression analysis showed that LVDD was one of the most powerful determinants of MACE and mortality after adjusting for all confounding factors (hazard ratio [HR]: 1.71, 95% confidence interval [CI]: 1.43-3.51, P = 0.02 and HR: 2.25, 95% CI: 1.45-2.91, P = 0.04, respectively). Systemic inflammation (hsCRP) was also significantly associated with MACE and mortality (HR: 2.03, P = 0.03 and HR: 2.16, P = 0.04, respectively). LVDD is associated with systemic inflammation and increased visceral fat in patients undergoing PD. LVDD is also a sensitive, independent indicator of future MACE and mortality in PD patients.