Excessive Weight Gain during the First Year of Peritoneal Dialysis Is Associated with Inflammation, Diabetes Mellitus, and a Rapid Decrease in Residual Renal Function

Influencing factors for residual kidney function in incident peritoneal dialysis patients: a systematic review and meta-analysis

BACKGROUND

Residual kidney function (RKF) impacts patients' survival rate and quality of life when undergoing peritoneal dialysis (PD). This meta-analysis was conducted to systematically identify risk and protective factors associated with RKF decline and loss.

METHODS

We searched three English and one Chinese databases from inception to January 31, 2023, for cohort and cross-sectional studies exploring factors associated with RKF decline or loss. The random effects model was employed to aggregate risk estimates and 95% confidence intervals (CIs) from multivariate analysis. Sensitivity and subgroup analyses were performed to explore the heterogeneity among the studies.

RESULTS

Twenty-seven studies comprising 13549 individuals and 14 factors were included in the meta-analysis. Based on the meta-analysis results, risk factors involving male gender (hazard ratio (HR) 1.689, 95%CI 1.385-2.061), greater body mass index (BMI) (odds ratio (OR) 1.081, 95% confidence interval (CI) 1.029-1.135), higher systolic blood pressure (SBP) (HR 1.014, 95%CI 1.005-1.024), diabetes mellitus (DM) (HRRKF loss 1.873, 95%CI 1.475-2.378), DM (ORRKF decline 1.906, 95%CI 1.262-2.879), peritonitis (relative ratio (RR) 2.291, 95%CI 1.633-3.213), proteinuria (OR 1.223, 95%CI 1.117-1.338), and elevated serum phosphorus (RR 2.655, 95%CI 1.679-4.201) significantly contributed to the risk of RKF decline and loss in PD patients. Conversely, older age (HR 0.968, 95%CI 0.956-0.981), higher serum albumin (OR 0.834, 95%CI 0.720-0.966), weekly Kt/V urea (HR 0.414, 95%CI 0.248-0.690), baseline urine volume (UV) (HR 0.791, 95%CI 0.639-0.979), baseline RKF (HR 0.795, 95%CI 0.739-0.857) exhibited protective effects. However, diuretics use, automatic peritoneal dialysis (APD) modality and baseline RKF did not significantly impact RKF decline.

CONCLUSIONS

Patients with male gender, greater BMI, higher SBP, DM, peritonitis, proteinuria, and elevated serum phosphorus might have a higher risk of RKF decline and loss. In contrast, older age, higher serum albumin, weekly Kt/V urea, baseline UV, and baseline RKF might protect against RKF deterioration.

Elevated Ferritin Levels Associated with High Body Fat Mass Affect Mortality in Peritoneal Dialysis Patients

Obesity is a common health problem in peritoneal dialysis (PD) patients and causes high serum ferritin levels. However, mixed results have been reported on whether serum ferritin levels affect the prognosis of PD patients. We investigated the effect of increased adiposity on ferritin levels and its association with mortality in 350 well-nourished PD patients. Body composition was measured using a portable whole-body bioimpedance spectroscope, and clinical determinants of high ferritin levels were evaluated. High ferritin levels (≥600 ng/mL) were observed in 63 (18.0%) patients. Patients with high ferritin levels had a significantly higher body fat percentage and a lower lean tissue index than patients with low or normal ferritin levels. During a median follow-up of 30 months, there were 65 deaths. Ferritin ≥ 600 ng/mL was associated with significantly higher all-cause mortality compared with 200-600 ng/mL of ferritin. Multivariate analysis showed that high ferritin levels were significantly associated with a higher percentage of body fat after adjustment for lean tissue index and volume status. High ferritin increased all-cause mortality in PD patients, and increased fat mass was an important determinant of the high ferritin. Our results support that adiposity may lead to an adverse clinical outcome in PD patients.

On the importance of the interplay of residual renal function with clinical outcomes in end-stage kidney disease

Chronic kidney disease (CKD) is one of the most important public health concerns of the century, and is associated with high rates of morbidity, mortality and social costs. CKD evolving towards end-stage kidney disease (ESKD) is on the rise resulting in a greater number of patients requiring peritoneal dialysis (PD) and hemodialysis (HD). The aim of this manuscript is to review the current literature on the interplay of residual renal function (RRF) with clinical outcomes in ESKD. The persistence of RRF is one of the most important predictors of decreased morbidity, mortality, and better quality of life in both PD and HD patients. RRF contributes to the well-being of ESKD patients through various mechanisms including higher clearance of solutes, maintenance of fluid balance, removal of uremic toxins and control of electrolytes. Furthermore, RRF has beneficial effects on inflammation, anemia, malnutrition, diabetes mellitus, obesity, changes in the microbiota, and cardiac diseases. Several strategies have been proposed to preserve RRF, such as blockade of the renin-angiotensin-aldosterone system, better blood pressure control, incremental PD and HD. Several clinical trials investigating the issue of preservation of RRF are ongoing. They are needed to broaden our understanding of the interplay of RRF with clinical outcomes in ESKD.

Adipose and Plasma microRNAs miR-221 and 222 Associate with Obesity, Insulin Resistance, and New Onset Diabetes after Peritoneal Dialysis

BACKGROUND

The correlation between microRNA, obesity, and glycemic intolerance in patients on peritoneal dialysis (PD) is unknown. We aimed to measure the adipose and plasma miR-221 and -222 levels, and to evaluate their association with adiposity, glucose intolerance, and new onset diabetes mellitus (NODM) after the commencement of PD.

METHODS

We prospectively recruited incident adult PD patients. miR-221 and -222 were measured from adipose tissue and plasma obtained during PD catheter insertion. These patients were followed for 24 months, and the outcomes were changes in adiposity, insulin resistance, and NODM after PD.

RESULTS

One hundred and sixty-five patients were recruited. Patients with pre-existing DM had higher adipose miR-221 (1.1 ± 1.2 vs. 0.7 ± 0.9-fold, p = 0.02) and -222 (1.9 ± 2.0 vs. 1.2 ± 1.3-fold, p = 0.01). High adipose miR-221 and -222 levels were associated with a greater increase in waist circumference (miR-221: beta 1.82, 95% CI 0.57-3.07, p = 0.005; miR-222: beta 1.35, 95% CI 0.08-2.63, p = 0.038), Homeostatic Model Assessment for Insulin Resistance (HOMA) index (miR-221: beta 8.16, 95% CI 2.80-13.53, p = 0.003; miR-222: beta 6.59, 95% CI 1.13-12.05, p = 0.018), and insulin requirements (miR-221: beta 0.05, 95% CI 0.006-0.09, p = 0.02; miR-222: beta 0.06, 95% CI 0.02-0.11, p = 0.002) after PD. The plasma miR-222 level predicted the onset of NODM (OR 8.25, 95% CI 1.35-50.5, p = 0.02).

CONCLUSION

miR-221 and -222 are associated with the progression of obesity, insulin resistance, and NODM after PD.

Obesity, Weight Gain, and Fluid Overload in Peritoneal Dialysis

Obesity is a global epidemic that has a complicated pathogenesis as well as impact on the outcome of peritoneal dialysis (PD) patients. In this review, the prevalence of obesity in incident PD patients as well as the phenomenon of new-onset glucose intolerance after PD will be reviewed. Published literature on the effect of obesity on the survival and incidence of cardiovascular disease in PD patients will be discussed. Particular emphasis would be put on literature that compared the impact of obesity on the outcome of hemodialysis and PD, and the confounding effect of dialysis adequacy. Next, the complex concept of obesity and its relevance for PD will be explored. The focus would be put on the methods of assessment and clinical relevance of central versus general obesity, as well as visceral versus subcutaneous adipose tissue. The relation between obesity and systemic inflammation, as well as the biological role of several selected adipokines will be reviewed. The confounding effects of metabolic syndrome and insulin resistance will be discussed, followed by the prevalence and prognostic impact of weight gain during the first few years of PD. The differences between weight gain due to fluid overload and accumulation of adipose tissue will be discussed, followed by the current literature on the change in body composition after patients are put on chronic PD. The methods of body composition will be reviewed, and the clinical relevance of individual body component (fluid, fat, muscle, and bone) will be discussed. The review will conclude by highlighting current gaps of knowledge and further research directions in this area.

Comparison of peritoneal dialysis and hemodialysis as first renal replacement therapy in patients with end-stage renal disease and diabetes: a systematic review

Background

Diabetes has become the most common cause of end-stage renal disease (ESRD) requiring renal replacement therapy (RRT) in most countries around the world. Peritoneal dialysis (PD) is valuable for patients newly requiring RRT because of the preservation of residual renal function (RRF), higher quality of life, and hemodynamic stability in comparison with hemodialysis (HD). A previous systematic review produced conflicting results regarding patient survival. As several advances have been made in therapy for diabetic patients receiving PD, we conducted a systematic review of studies published after 2014 to determine whether incident PD or HD is advantageous for the survival of patients with diabetes.

Methods

For this systematic review, the MEDLINE, EMBASE, and CENTRAL databases were searched to identify articles published between February 2014 and August 2017. The quality of studies was assessed using the GRADE approach. Outcomes of interest were all-cause mortality; RRF; major morbid events, including cardiovascular disease (CVD) and infectious disease; and glycemic control. This review was performed using a predefined protocol published in PROSPERO (CRD42018104258).

Results

Sixteen studies were included in this review. All were retrospective observational studies, and the risk of bias, especially failure to adequately control confounding factors, was high. Among them, 15 studies investigated all-cause mortality in diabetic patients initiating PD and HD. Differences favoring HD were observed in nine studies, whereas those favoring PD were observed in two studies. Two studies investigated effects on CVD, and both demonstrated the superiority of incident HD. No study investigated the effect of any other outcome.

Conclusions

In the present systematic review, the risk of death tended to be higher among diabetic patients with ESRD newly initiating RRT with incident PD in comparison with incident HD. However, we could not obtain definitive results reflecting the superiority of PD or HD with regard to patient outcomes because of the severe risk of bias and the heterogeneity of management strategies for diabetic patients receiving dialysis. Further studies are needed to clarify the advantages of PD and HD as RRT for diabetic patients with ESRD.

Effects of Excessive Body Fat Accumulation on Long-Term Outcomes During Peritoneal Dialysis

Background:Significant body fat accumulation is an inevitable but potentially serious problem in peritoneal dialysis (PD) patients. Whether excessive fat gain predicts long-term outcomes in these patients remains unknown.Methods:In this prospective cohort study (n = 297), the associations of excessive fat accumulation with patient survival and PD failure rate were examined. Based on dialysis duration at the time of study enrollment, patients were divided into short- (< 2 years) and long-term (> 2 years) groups. Body weight (BW) and body composition were measured twice, 12.8 ± 4.6 months apart. Excessive fat accumulation was defined as a 1-year change in the percentage of body fat (ΔPBF) over the highest quartile (5.0% for men, 5.4% for women).Results:Substantial 1-year increases in BW and PBF were observed only in the short-term group (p < 0.001 and p = 0.027, respectively); changes were insignificant in the long-term group. In the short-term group, the ΔPBF was associated closely with unfavorable baseline metabolic profiles, including old age, diabetes, obesity, elevated blood pressure, and edema. Accordingly, the mortality rate was significantly higher in patients with, than in those without, excessive fat accumulation (hazard ratio [HR] 3.26, 95% confidence interval [CI], 1.05 - 10.26). It also increased the incident risk of PD failure 2.22-fold (95% CI, 1.08 - 4.54), even after adjustment for diabetes, obesity, and fluid status. In the long-term group, fat gain had no impact on long-term prognosis.Conclusions:Excessive fat accumulation during the early period of PD was associated with baseline unhealthy metabolic profiles, a higher mortality rate, and a higher PD failure rate, independent of baseline obesity and fluid status.

A Fast Decline of Residual Renal Function in the First Year is a Predictor for Early Withdrawal from Peritoneal Dialysis in Non-Diabetic Patients

BACKGROUND/AIMS

Little is known about the relationship between residual renal function (RRF) decline in early period and survival in non-diabetic peritoneal dialysis (PD) patients.

METHODS

A total of 567 non-diabetic patients who began PD from January 1, 2005 to June 30, 2013 was investigated. The rate of RRF decline was determined by the "slope of the trend equation" of serial RRFs. A composite end-point of all-cause mortality and conversion to hemodialysis (HD) was used, survival status was censored on June 30, 2016.

RESULTS

The median of "the slope of RRF decline equation" was 0.308 (0.001-2.111) ml/min/1.73 m2/ month. In the median follow-up period of 43 months (range 12 to 120 months), 65 (11.5%) patients died, 90 (15.9%) patients converted to HD and 171 (30.2%) patients received kidney transplantation. Multivariate linear regression showed male, high baseline RRF, high baseline peritoneal Kt/V urea, low serum albumin and low uric acid were independently associated with the rate of RRF decline in the first year of PD. Multivariate Cox models revealed that RRF decline in the first year remained a predictor for composite end-point (HR, 2.74, 95% CI, 1.53 to 4.90, P=0.001). The patients were divided into high RRF decline group (> 0.308ml/ min/1.73m2/month) and low RRF decline group (≤0.308 ml/min/1.73m2/month). In the first three years of PD, the rate of end-point events was higher in high RRF decline group (23.2%) than that in low RRF decline group (11.0%) (P< 0.001). There were 189 patients in low RRF decline group and 171 patients in high RRF decline group maintaining PD for more than 3 years, in a median follow-up of 54 months (range 37 to 120 months), the survival rate was 30.9% in high RRF decline group and 46.4% in low RRF decline group (P=0.883). In high RRF decline group, there were 92 patients reaching composited end-point and 112 patients maintaining PD; multivariate Cox model showed high peritoneal Kt/V urea after 1 year of PD and high albumin level were protective factors (HR, 0.29, 95% CI, 0.13 to 0.61, P= 0.001; HR, 0.94, 95% CI, 0.90-0.99, P=0.022, respectively), while fast RRF decline remained risk factor for composite end-point (HR, 3.28, 95% CI,1.48-7.31, P=0.004).

CONCLUSION

A faster RRF decline in the first year was a predictor for all-cause mortality and conversion to HD in non-diabetic PD patients, mainly in the first three year. For patients with faster RRF decline, increasing PD dose was effective to improve survival.

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.

Impact of Diabetes on Extracellular Volume Status in Patients Initiating Peritoneal Dialysis

BACKGROUND

Recent reports have highlighted that diabetic patients with kidney failure are at increased risk of technique failure and transfer to haemodialysis within 90 days of initiating peritoneal dialysis (PD). We wished to determine whether there were differences between diabetic and non-diabetic patients within the first 3 months of starting PD.

METHODS

We reviewed results of corresponding bioimpedance and the 1st test of peritoneal membrane function (PET) in consecutive patients, 6-10 weeks after initiating PD electively.

RESULTS

Adult patients numbering 386 - 230 males (59.6%), 152 (39.4%) diabetic, 188 (48.7%) white, mean age 57.3 ±16.9 years - were studied. Although weight, residual renal function and peritoneal clearances were not different, diabetic patients had greater extracellular water to total body water (ECW/TBW; 40.4 ± 1.1 vs. 39.2 ± 1.4) and % ECW excess (9.6 [6.3-12.3] vs. 4.9 [0.7-8.9]), lower serum albumin (35.2 ± 4.7 vs. 37.8 ± 4.9 g/L), greater fat mass index (9.5 ± 4.2 vs. 7.7 ± 4.2), and although mean arterial blood pressure was similar, arterial pulse pressure was greater (66.9 ± 10.8 vs. 54.3 ± 17.3 mm Hg, all p < 0.001). On multivariate analysis, glycated haemoglobin was associated with pulse pressure (standardised β 0.24, p < 0.001), N terminal brain natriuretic peptide (β 0.24, p < 0.001), ECW/TBW (β 0.19, p = 0.012) and negatively with serum albumin (β -0.14, p = 0.033) and creatinine (β -0.18, p = 0.02).

CONCLUSION

Diabetic patients electively starting PD were found to have greater ECW/TBW ratios and ECW excess 6-10 weeks after starting PD compared to non-diabetics, despite similar PET. Increased ECW could predispose diabetic patients to be at greater risk of volume overload.

Advances in Understanding and Management of Residual Renal Function in Patients with Chronic Kidney Disease

BACKGROUND

Residual renal function (RRF), defined as the ability of native kidneys to eliminate water and uremic toxins, is closely correlated with mortality and morbidity rates among patients receiving either peritoneal dialysis (PD) or hemodialysis (HD) via continuous clearance of middle-sized molecules and protein-bound solutes. Therefore, preserving RRF is considered to be one of the primary goals in managing patients with end-stage renal disease (ESRD).

SUMMARY AND KEY MESSAGES

In this article, we provide a review on the understanding and management of RRF in patients on dialysis. RRF may be estimated and measured by calculating the mean 24-hour urine creatinine level and urea clearance. Currently, several middle-sized molecules are reported but rarely used in practice. Many risk factors such as original renal diseases, dietary intake, and nephrotoxic agents impair RRF. Targeting such factors may halt the decline in RRF and offer better outcomes for patients on PD or HD. Except for in PD patients, RRF is a powerful predictor of survival in HD patients. RRF requires more clinical and research attention in the care of patients with ESRD on dialysis.