Association of body weight changes with mortality in incident hemodialysis patients

Treatment of Type 2 Diabetes Mellitus in Advanced Chronic Kidney Disease for the Primary Care Physician

Diabetes mellitus (DM) is a common cause of chronic kidney disease (CKD), leading to the need for renal replacement therapy (RRT). RRT includes hemodialysis (HD), peritoneal dialysis (PD), kidney transplantation (KT), and medical management. As CKD advances, the management of DM may change as medication clearance, effectiveness, and side effects can be altered due to decreasing renal clearance. Medications like metformin that were safe to use early in CKD may build up toxic levels of metabolites in advanced CKD. Other medications, like sodium-glucose co-transporter 2 inhibitors, which work by excreting glucose in the urine, may not be able to work effectively in advanced CKD due to fewer working nephrons. Insulin breakdown may take longer, and both formulation and dosing may need to be changed to avoid hypoglycemia. While DM control contributes to CKD progression, effective DM control continues to be important even after patients have been placed on RRT. Patients on RRT are frequently taken care of by a team of providers, including the primary care physician, both in and outside the hospital. Non-nephrologists who are involved with the care of a patient treated with RRT need to be adept at managing DM in this population. This paper aims to outline the management of type 2 DM in advanced CKD.

Prevalence of physical frailty and impact on survival in patients with chronic kidney disease: a systematic review and meta-analysis

BACKGROUND

Frailty is common in chronic kidney disease (CKD) patients and becomes more prevalent as kidney disease progresses. This study aimed to investigate the prevalence of physical frailty and quantify the relationship between frailty and mortality risk in patients with CKD.

METHODS

PubMed, Web of Science, Embase, Cochrane Central Register of Controlled Trials, Clinicaltrial.gov, and major renal academic conferences were systematically searched, and additional references to relevant articles were manually searched. The prevalence of physical frailty and the risk of mortality based on random-effects models were assessed using percentages and hazard ratio (HR) with a 95% confidence interval (CI).

RESULTS

A total of 139 articles, including 1,675,482 participants, met the eligibility criteria for the meta-analysis. The results showed that 34.5% (95% CI 31.0 to 38.1%) of CKD patients showed signs of frailty, and 39.4% (95% CI 35.4 to 43.5%) had prefrail symptoms. Compared to non-frail patients, the risk of mortality was increased by 94.1% (95% CI 1.586 to 2.375) in frail patients and 34.5% (95% CI 1.231 to 1.469) in prefrail patients.

CONCLUSION

The high prevalence of frailty and prefrail in adults with CKD and resulting in premature death emphasize the importance of measuring frailty, which provides important prognostic information and may provide opportunities for interventions to improve the prognosis of patients with CKD.

Obesity Weight Loss Phenotypes in CKD: Findings From the Chronic Renal Insufficiency Cohort Study

Introduction

Although people with chronic kidney disease (CKD) and obesity have important motivations to lose weight, weight loss is also associated with health risks. We examined whether patterns of change in systolic blood pressure (SBP), serum albumin level, and fat-free mass (FFM) can help to differentiate between healthy and high-risk weight loss in this population.

Methods

Using data from the Chronic Renal Insufficiency Cohort Study (CRIC), we estimated a joint multivariate latent class model with 6 classes to identify distinct trajectories of body mass index (BMI), albumin, and SBP among participants with obesity (BMI ≥30 kg/m2 at baseline), accounting for informative missingness from death. In a secondary analysis, we fit a 6-class model with BMI and FFM.

Results

Among 2831 participants (median baseline BMI 35.6, interquartile range [IQR] 32.4-40.0 kg/m2), median follow-up was 6.8 (IQR 4.8-12.9) years, median age was 61 (IQR 54-67) years, 53% were male, 50% were non-Hispanic Black, and 82% were trying to control or lose weight at baseline. Latent classes were associated with mortality risk (5-year cumulative incidence of mortality 6.8% and 1.5% in class 6 and 3, respectively). Class 6 had the highest mortality rate and was characterized by early, steep BMI loss, early serum albumin decline, and late SBP increase. In the secondary analysis, a class characterized by steep BMI and FFM loss was associated with the highest death risk.

Conclusions

Among adults with CKD and obesity, BMI loss with concomitant serum albumin or FFM loss was associated with a high risk of death.

Chronic Kidney Disease and Obesity

There is a pandemic of obesity worldwide and in Europe up to 30% of the adult population is already obese. Obesity is strongly related to the risk of CKD, progression of CKD, and end-stage renal disease (ESRD), also after adjustment for age, sex, race, smoking status, comorbidities, and laboratory tests. In the general population, obesity increases the risk of death. In nondialysis-dependent CKD patients, the association between body mass index and weight with mortality is controversial. In ESRD patients, obesity is paradoxically associated with better survival. There are only a few studies investigating changes in weight in these patients and in most weight loss was associated with higher mortality. However, it is not clear if weight change was intentional or unintentional and this is an important limitation of these studies. Management of obesity includes life-style interventions, bariatric surgery, and pharmacotherapy. In the last 2 years, a long-acting glucagon-like peptide-1 (GLP-1) receptor agonist and GLP-1 and glucose-dependent insulinotropic polypeptide receptor agonist were shown to be effective in managing weight loss in non-CKD patients, but we are awaiting results of more definitive studies in CKD patients.

Adipose and serum zinc alpha-2-glycoprotein (ZAG) expressions predict longitudinal change of adiposity, wasting and predict survival in dialysis patients

There were limited data on adipose and serum zinc alpha-2-glycoprotein (ZAG) expression and its association with body composition in patients with advanced chronic kidney disease (CKD). This study aimed to quantify adipose and serum ZAG expression and evaluate their association with body composition and its longitudinal change, together with mortality in incident dialysis patients. We performed a single-center prospective cohort study. Patients who were planned for peritoneal dialysis were recruited. ZAG levels were measured from serum sample, subcutaneous and pre-peritoneal fat tissue obtained during peritoneal dialysis catheter insertion. Body composition and functional state were evaluated by bioimpedance spectroscopy and Clinical Frailty Scale respectively at baseline and were repeated 1 year later. Primary outcome was 2-year survival. Secondary outcomes were longitudinal changes of body composition. At baseline, the average adipose and serum ZAG expression was 13.4 ± 130.0-fold and 74.7 ± 20.9 µg/ml respectively. Both adipose and serum ZAG expressions independently predicted adipose tissue mass (ATM) (p = 0.001, p = 0.008, respectively). At 1 year, ATM increased by 3.3 ± 7.4 kg (p < 0.001) while lean tissue mass (LTM) remained similar (p = 0.5). Adipose but not serum ZAG level predicted change in ATM (p = 0.007) and LTM (p = 0.01). Serum ZAG level predicted overall survival (p = 0.005) and risk of infection-related death (p = 0.045) after adjusting for confounders. In conclusion, adipose and serum ZAG levels negatively correlated with adiposity and predicted its longitudinal change of fat and lean tissue mass, whilst serum ZAG predicted survival independent of body mass in advanced CKD patient.

Assessment of cerebral oxygenation response to hemodialysis using near-infrared spectroscopy (NIRS): Challenges and solutions

To date, the clinical use of functional near-infrared spectroscopy (NIRS) to detect cerebral ischemia has been largely limited to surgical settings, where motion artifacts are minimal. In this study, we present novel techniques to address the challenges of using NIRS to monitor ambulatory patients with kidney disease during approximately eight hours of hemodialysis (HD) treatment. People with end-stage kidney disease who require HD are at higher risk for cognitive impairment and dementia than age-matched controls. Recent studies have suggested that HD-related declines in cerebral blood flow might explain some of the adverse outcomes of HD treatment. However, there are currently no established paradigms for monitoring cerebral perfusion in real-time during HD treatment. In this study, we used NIRS to assess cerebral hemodynamic responses among 95 prevalent HD patients during two consecutive HD treatments. We observed substantial signal attenuation in our predominantly Black patient cohort that required probe modifications. We also observed consistent motion artifacts that we addressed by developing a novel NIRS methodology, called the HD cerebral oxygen demand algorithm (HD-CODA), to identify episodes when cerebral oxygen demand might be outpacing supply during HD treatment. We then examined the association between a summary measure of time spent in cerebral deoxygenation, derived using the HD-CODA, and hemodynamic and treatment-related variables. We found that this summary measure was associated with intradialytic mean arterial pressure, heart rate, and volume removal. Future studies should use the HD-CODA to implement studies of real-time NIRS monitoring for incident dialysis patients, over longer time frames, and in other dialysis modalities.

Obesity and bariatric surgery in kidney transplantation: A clinical review

Obesity is increasing worldwide, and this has major implications in the setting of kidney transplantation. Patients with obesity may have limited access to transplantation and increased posttransplant morbidity and mortality. Most transplant centers incorporate interventions aiming to target obesity in kidney transplant candidates, including dietary education and lifestyle modifications. For those failing nutritional restriction and medical therapy, the use of bariatric surgery may increase the transplant candidacy of patients with obesity and end-stage renal disease (ESRD) and may potentially improve the immediate and late outcomes. Bariatric surgery in ESRD patients is associated with weight loss ranging from 29.8% to 72.8% excess weight loss, with reported mortality and morbidity rates of 2% and 7%, respectively. The most commonly performed bariatric surgical procedures in patients with ESRD and in transplant patients are laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass. However, the correct timing of bariatric surgery and the ideal type of surgery have yet to be determined, although pretransplant LSG seems to be associated with an acceptable risk-benefit profile. We review the impact of obesity on kidney transplant candidates and recipients and in potential living kidney donors, exploring the potential impact of bariatric surgery in addressing obesity in these populations, thereby potentially improving posttransplant outcomes.

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.

Changes in metabolic syndrome status affect the incidence of end-stage renal disease in the general population: a nationwide cohort study

Few studies have investigated the impact of a change in metabolic syndrome (MetS) components on clinical renal outcomes in the general population. Using nationally representative data from the Korean National Health Insurance System, 13,310,924 subjects who underwent two health examinations over 2 years and were free from end-stage renal disease (ESRD) from 2009 to 2012 were followed to the end of 2016. The subjects were divided into four groups according to the change in MetS components between the two visits over 2 years: no MetS (–/–), post-MetS (–/+), pre-MetS (+/–), and both MetS (+/+). After a median follow up of 5.11 years, 18,582 incident ESRD cases were identified. In the multivariate adjusted model, the hazard ratio (HR) and 95% confidence interval (CI) for the development of ESRD in the both-MetS (+/+) group compared with the no-MetS (–/–) group was 5.65 (95% CI, 5.42–5.89), which was independent of age, sex, and baseline estimated glomerular filtration rate. Additionally, the HR for the pre-MetS (+/–) group versus the no-MetS (–/–) group was 2.28 (2.15–2.42). In subgroup analysis according to renal function, the impact of a change in MetS on the incidence of ESRD was more pronounced in individuals with advanced renal dysfunction. Subjects with resolved MetS components had a decreased risk of ESRD, but not as low as those that never had MetS components. This provides evidence supporting the strategy of modulating MetS in the general population to prevent the development of ESRD.

Impact of old age on the association between in-center extended-hours hemodialysis and mortality in patients on incident hemodialysis

With the global problem of aging, it has become more difficult to improve the prognosis of older dialysis patients. Extended-hours hemodialysis offers longer treatment time compared to conventional hemodialysis regimen and provides favorable metabolic status, hemodynamic stability, and increased dietary intake. Despite prior studies reporting that in-center extended-hours hemodialysis can reduce the mortality rate, the treatment impact on elderly patients remains unclear. Therefore, we examined the association between extended-hours hemodialysis compared to conventional hemodialysis and all-cause mortality. Survival analyses using Cox proportional hazard model with multivariable adjustments and propensity-score based method were performed to compare mortality risk between 198 consecutive patients who started in-center extended-hours hemodialysis (Extended-HD) and 1407 consecutive patients who initiated conventional hemodialysis. The median age was 67.1 years in the Extended-HD group and 70.7 years in the conventional hemodialysis group. Extended-HD was associated with lower all-cause mortality in overall patients and the subgroup >70 years (adjusted hazard ratios of 0.60 [95% CI, 0.39–0.91] and 0.35 [95% CI, 0.18–0.69], respectively). There was a significant interaction between age >70 years and Extended-HD. In conclusion, extended-hours hemodialysis was associated with a lower mortality rate, especially in elderly patients.

Approaches to Obesity Management in Dialysis Settings: Renal Dietitian Perspectives

OBJECTIVES

Over 40% of individuals in the United States with end-stage kidney disease have obesity. Little is known about renal dietitian perspectives on obesity management in the setting of dialysis dependence.

DESIGN AND METHODS

An online 21-item survey was distributed to 118 renal dietitians via individual outreach and a professional organization e-mail listserv. Four themes were explored: the burden of obesity among dialysis patients, concepts of healthy weight loss, weight loss approaches, and challenges of obesity management in dialysis settings. Respondents were asked to rank approaches and biomarkers for obesity management from 0 (least important or not used) to 100 (most important). Free text fields were provided in each category for additional comments.

RESULTS

Thirty-one renal dietitians responded to the survey (26% response rate). The majority of respondents (90%) indicated that access to kidney transplantation was the main reason that dialysis patients with obesity desired weight loss. Calorie restriction was rated as the most common weight loss approach, and dry weight as the most important weight loss biomarker. Nearly 40% of respondents do not alter their nutritional approach when dialysis patients with obesity are losing weight, and 42% of respondents do not monitor changes in waist circumference. Exercise, diet counseling, and stress management were variably prioritized as weight loss management strategies. Barriers to obesity management in dialysis settings included lack of time, lack of training in weight loss counseling, and gaps in current renal nutritional guidelines.

CONCLUSION

Despite the high prevalence of obesity among individuals with end-stage kidney disease, the results of this survey suggest that current approaches to obesity management in dialysis settings are highly variable. Many renal dietitians lack time to counsel patients on healthy weight loss strategies. Nutritional guidelines are also needed to support people with dialysis dependence and obesity who desire or require weight loss.

Cardiac MRI measurements of pericardial adipose tissue volumes in patients on in-centre nocturnal hemodialysis

BACKGROUND

Conversion from conventional hemodialysis (CHD) to in-centre nocturnal hemodialysis (INHD) is associated with left ventricular (LV) mass regression, but the underlying mechanisms are not fully understood. Using cardiac MRI (CMR), we examined the effects of INHD on epicardial adipose tissue (EAT) and paracardial adipose tissue (PAT), and the relationships between EAT, PAT and LV remodeling, biomarkers of nutrition, myocardial injury, fibrosis and volume.

METHODS

We conducted a prospective multicenter cohort study of 37 patients transitioned from CHD to INHD and 30 patients on CHD (control). Biochemical markers and CMR were performed at baseline and 52 weeks. CMR images were analyzed by independent readers, blinded to order and treatment group.

RESULTS

Among 64 participants with complete CMR studies at baseline (mean age 54; 43% women), there were no significant differences in EAT index (60.6 ± 4.3 mL/m² vs 64.2 ± 5.1 mL/m², p = 0.99) or PAT index (60.0 ± 5.4 mL/m² vs 53.2 ± 5.9 mL/m², p = 0.42) between INHD and CHD groups. Over 52 weeks, EAT index and PAT index did not change significantly in INHD and CHD groups (p = 0.21 and 0.14, respectively), and the changes in EAT index and PAT index did not differ significantly between INHD and CHD groups (p = 0.30 and 0.16, respectively). Overall, changes in EAT index inversely correlated with changes in LV end-systolic volume index (LVESVI) but not LV end-diastolic volume index (LVEDVI), LV mass index (LVMI), and LV ejection fraction (LVEF). Changes in PAT index inversely correlated with changes in LVESVI, LVMI and positively correlated with changes in LVEF. There were no correlations between changes in EAT index or PAT index with changes in albumin, LDL, triglycerides, troponin-I, FGF-23, or NT-proBNP levels over 52 weeks (all p > 0.30).

CONCLUSIONS

INHD was not associated with any changes in EAT index and PAT index over 12 months. Changes in EAT index were not significantly associated with changes in markers of LV remodeling, nutrition, myocardial injury, fibrosis, volume status. In contrast, changes in PAT index, which paradoxically is expected to exert less paracrine effect on the myocardium, were correlated with changes in LVESVI, LVMI and LVEF. Larger and longer-term studies may clarify the role of PAT in cardiac remodeling with intensified hemodialysis. CLINICALTRIALS.

GOV IDENTIFIER

NCT00718848.

Association Between Weight Loss Before Deceased Donor Kidney Transplantation and Posttransplantation Outcomes

RATIONALE & OBJECTIVE

There is debate on whether weight loss, a hallmark of frailty, signals higher risk for adverse outcomes among recipients of deceased donor kidney transplantation (DDKT).

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Using national Organ Procurement and Transplantation Network data, we included all DDKT recipients in the United States between December 4, 2004, and December 3, 2014, who were adults (aged ≥ 18 years) when listed for DDKT.

EXPOSURES

Relative pre-DDKT weight change as a continuous predictor and categorized as <5% weight change from listing to DDKT, ≥5% to <10% weight loss, ≥10% weight loss, ≥5% to <10% weight gain, and ≥10% weight gain.

OUTCOMES

We examined 3 post-DDKT outcomes: (1) transplant hospitalization length of stay (LOS) in days, (2) all-cause graft failure, and (3) mortality.

ANALYTIC APPROACH

Unadjusted fractional polynomial methods, multivariable log-gamma models, and multivariable Cox proportional hazards models.

RESULTS

Among 94,465 recipients of DDKT, median pre-DDKT weight change was 0 (interquartile range, -3.5 to +3.9) kg. There were nonlinear unadjusted associations between relative pre-DDKT weight loss and longer transplant hospitalization LOS, higher all-cause graft loss, and higher mortality. Compared with recipients with <5% pre-DDKT weight change (n = 49,366; 52%), recipients who lost ≥10% of their listing weight (n = 10,614; 11%) had 0.66 (95% CI, 0.23-1.09) days longer average transplant hospitalization LOS (P = 0.003), 1.11-fold higher graft loss (adjusted HR [aHR], 1.11; 95% CI, 1.06-1.17; P < 0.001), and 1.18-fold higher mortality (aHR, 1.18; 95% CI, 1.11-1.25; P < 0.001) independent of recipient, donor, and transplant factors. Pre-DDKT dialysis exposure, listing body mass index category, and waiting time modified the association of pre-DDKT weight change with hospital LOS (interaction P < 0.10), but not with all-cause graft loss and mortality.

LIMITATIONS

Unmeasured confounders and inability to identify volitional weight change. Also, the higher significance level set to increase the power of detecting interactions with the fixed sample size may have resulted in increased risk for type 1 error.

CONCLUSIONS

DDKT recipients with ≥10% pre-DDKT weight loss are at increased risk for adverse outcomes and may benefit from augmented support post-DDKT.

Association between BMI changes and mortality risk in children with end-stage renal disease

BACKGROUND

Few studies have examined how changes in BMI [body mass index] over time associate with risk of adverse outcomes in children receiving renal replacement therapy [RRT]. The objective of this study was to examine the association between annualized changes in BMI and the risk of death in children treated with RRT.

METHODS

We performed a retrospective cohort study of 1182 pediatric dialysis and transplant patients in the Pediatric Growth and Development Special Study of the United States Renal Data System. Quintiles of annualized change in BMI z-score (with cutoffs of - 0.50, - 0.13, 0.09, 0.57) were used as the primary predictor, with the middle quintile (- 0.13 to 0.09) serving as the reference category. Cox models were used to examine the association between exposure and death, with time of analysis starting from the second BMI measurement.

RESULTS

Median follow-up time to death or censoring was 6 years. Median age was 14.6 years, and 61% of children had a functional graft at cohort entry. There was a U-shaped association between BMI change and mortality risk: a large decline in annualized BMI z-score change (> - 0.50) was associated with an increased risk of death (adjusted hazard ratio [aHR] 1.54 (95% CI 1.17-2.03), p = 0.002). A large increase in annualized BMI z-score change (> 0.57) was also associated with an increased risk of death (aHR 1.44 (95% CI 1.07-1.92), p = 0.02). No interaction was noted between annualized BMI change and initial treatment modality (dialysis or transplant, p = 0.15).

CONCLUSIONS

Maintenance of a stable BMI in pediatric patients receiving RRT may be associated with improved survival.

The obesity paradox: A further consideration in dialysis patients

Several epidemiological cohorts have demonstrated that higher body mass index (BMI) is associated with lower mortality risk among patients receiving hemodialysis. However, BMI may be an inaccurate indicator of nutritional status among dialysis patients because it does not differentiate between muscle and fat mass or provide information about body fat distribution. More sophisticated methods of body composition analysis are therefore required to address the question of which component is associated with greater survival. Recent evidence has also shown that changes in body weight and body composition are more strongly associated with mortality in dialysis patients than measurement of BMI at a single time point. Given that obesity is common among the dialysis population, weight loss interventions are encouraged for obese dialysis patients who are on a transplant waiting list in order to increase the access for transplantation.

Lower body mass index and mortality in older adults starting dialysis

Lower body mass index (BMI) has consistently been associated with mortality in elderly in the general and chronic disease populations. Remarkably, in older incident dialysis patients no association of BMI with mortality was found. We performed an in-depth analysis and explored possible time-stratified effects of BMI. 908 incident dialysis patients aged ≥65 years of the NECOSAD study were included, and divided into tertiles by baseline BMI (<23.1 (lower), 23.1–26.0 (reference), ≥26.0 (higher) kg/m²). Because the hazards changed significantly during follow-up, the effect of BMI was modeled for the short-term (<1 year) and longer-term (≥1 year after dialysis initiation). During follow-up (median 3.8 years) 567 deaths occurred. Lower BMI was associated with higher short-term mortality risk (adjusted-HR 1.63 [1.14–2.32] P = 0.007), and lower longer-term mortality risk (adjusted-HR 0.81 [0.63–1.04] P = 0.1). Patients with lower BMI who died during the first year had significantly more comorbidity, and worse self-reported physical functioning compared with those who survived the first year. Thus, lower BMI is associated with increased 1-year mortality, but conditional on surviving the first year, lower BMI yielded a similar or lower mortality risk compared with the reference. Those patients with lower BMI, who had limited comorbidity and better physical functioning, had better survival.

Modeling longitudinal data and its impact on survival in observational nephrology studies: tools and considerations

Nephrologists and kidney disease researchers are often interested in monitoring how patients' clinical and laboratory measures change over time, what factors may impact these changes, and how these changes may lead to differences in morbidity, mortality, and other outcomes. When longitudinal data with repeated measures over time in the same patients are available, there are a number of analytical approaches that could be employed to describe the trends and changes in these measures, and to explore the associations of these changes with outcomes. Researchers may choose a streamlined and simplified analytic approach to examine trajectories with subsequent outcomes such as estimating deltas (subtraction of the last observation from the first observation) or estimating per patient slopes with linear regression. Conversely, they could more fully address the data complexity by using a longitudinal mixed model to estimate change as a predictor or employ a joint model, which can simultaneously model the longitudinal effect and its impact on an outcome such as survival. In this review, we aim to assist nephrologists and clinical researchers by reviewing these approaches in modeling the association of longitudinal change in a marker with outcomes, while appropriately considering the data complexity. Namely, we will discuss the use of simplified approaches for creating predictor variables representing change in measurements including deltas and patient slopes, as well more sophisticated longitudinal models including joint models, which can be used in addition to simplified models based on the indications and objectives of the study as warranted.

Nutritional status after conversion from conventional to in-centre nocturnal hemodialysis

INTRODUCTION

Recipients of conventional hemodialysis (CHD; 3-4 h/session, 3 times/week) experience volume expansion and nutritional impairment which may contribute to high mortality. Prolongation of sessions with in-centre nocturnal hemodialysis (INHD; 7-8 h/session, 3 times/week) may improve clinical outcomes by enhancement of ultrafiltration and uremic toxin removal.

MATERIALS AND METHODS

In this prospective cohort study, 56 adult patients who were receiving maintenance CHD for at least 90 days were assigned to CHD (patients who remained in CHD) and INHD (patients who switched to INHD) groups. Both groups were followed for 1 year divided into four 13-week quarters; post-dialysis weight and interdialytic weight gain (IDWG) were captured in each quarter. Repeated measures analysis of variance was used to calculate group main effect, time main effect or time-group interaction effect.

RESULTS

Conversion to INHD was associated with a mean (95% confidence interval) change in IDWG of 0.5 (0.08, 1.2) kg as compared to -0.3 (-0.9, 0.1) kg in the CHD group (p < 0.01). In the INHD group, post-dialysis weight (% of baseline pre-dialysis weight) decreased after conversion, reaching a nadir during the first 3 months (0.7%) and subsequently it gradually increased and returned to its baseline at the end of follow-up. A similar temporal trend was seen for serum creatinine but not serum N-terminal pro-brain natriuretic peptide (NT-proBNP) which is a marker of extracellular volume. The changes in serum albumin, prealbumin and hs-CRP were not different between the two groups.

CONCLUSIONS

Conversion to INHD was associated with greater IDWG and relatively stable body mass. We speculate that this gain in weight reflects an increase in lean body mass following the change in dialysis modality, which can be concluded from the parallel increase in serum creatinine and the lack of increase in NT-proBNP.

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.