Self-reported Urine Volume in Hemodialysis Patients: Predictors and Mortality Outcomes in the International Dialysis Outcomes and Practice Patterns Study (DOPPS)

Volume Assessment in Patients Undergoing Long-Term Dialysis

Accurate assessment of fluid status is a priority for patients with kidney failure undergoing long-term dialysis. There is wide variation in current volume-related practices between dialysis units and an urgent need to develop better evidence to guide practice. Clinical decisions relating to volume management are implicitly based on assessment of volume status, and there are numerous different but imperfect methods of assessment. Isotope-based dilutions are impractical for clinical use and may not be a gold standard for patients with kidney failure. Individual trends in body weight and BP have been used as a pragmatic surrogate marker for volume status. Probing the target weight based on BP is still widely practiced but may pose risks related to volume depletion and accelerated loss of residual kidney function. Clinical signs, such as elevated jugular venous pressure and leg edema, are readily accessible but have poor diagnostic accuracy and wide interobserver variability that limit their reproducibility for volume assessment in clinical trials. Lung ultrasound and bioelectrical impedance analysis have a sound scientific rationale for the assessment of extracellular volume and are appropriately associated with clinical outcomes, but neither approach has demonstrated convincingly favorable clinical outcomes in clinical trials. Other technologies for volume assessment exist but require further assessment in clinical trials. Advancements in clinical care can be made with existing technologies through comparative effectiveness trials of different fluid management strategies, routine and standardized measurement of volumetric parameters and individual patient preferences, and innovative integration of existing volume assessment methods. A systematic and globally coordinated approach to improving volume assessment and management is required to improve outcomes in patients receiving long-term dialysis.

The comprehensive incidence and risk factors of fracture in kidney transplant recipients: A meta-analysis

AIM

Kidney transplant recipients are at high risk of fracture due to many factors such as nutritional status, hyperparathyroidism, acidosis and steroid administration. The current meta-analysis aimed to comprehensively analyse the incidence and risk factors of fracture in kidney transplant recipients.

METHODS

A systematic search on Embase, Web of Science, PubMed and Cochrane Library until November 2023 was performed. RStudio software was used to analyse data.

RESULTS

Twenty-eight eligible studies containing 310 530 kidney transplant recipients were included in the analysis. The pooled incidence of fracture was 10% (95% confidence interval [CI]: 7%-13%) generally. When divided by regions, it was further observed that the pooled incidence of fracture was 13% (95% CI: 9%-17%) in Europe, 11% (95% CI: 6%-16%) in North America, 7% (95% CI: 3%-11%) in Asia. Regarding the risk factors, pooled analysis revealed that age of recipient (hazard ratio [HR] = 1.50, 95% CI: 1.17-1.91), female sex (HR = 1.45, 95% CI: 1.36-1.53), pretransplantation diabetes (HR = 1.76, 95% CI: 1.58-1.97), pretransplantation fracture history (HR = 2.28, 95% CI: 1.86-2.78), dialysis duration (HR = 1.09, 95% CI: 1.01-1.17) and deceased donor (HR = 1.21, 95% CI: 1.05-1.39) related to higher risk of fracture. The general quality of included studies was acceptable, and no publication bias existed except for the analysis between age of recipient and fracture incidence; further trim and fill method indicated age of recipient showed a correlation trend with the fracture incidence without the statistical significance.

CONCLUSION

The pooled incidence of fracture reaches 10% in kidney transplant recipients, which relates to age of recipient, female sex, pretransplantation diabetes or fracture history, dialysis duration and decease donor.

Bio-impedance spectroscopy added to a fluid management protocol does not improve preservation of residual kidney function in incident hemodialysis patients in a randomized controlled trial

Avoiding excessive dialysis-associated volume depletion may help preserve residual kidney function (RKF). To establish whether knowledge of the estimated normally hydrated weight from bioimpedance measurements (BI-NHW) when setting the post-hemodialysis target weight (TW) might mitigate rate of loss of RKF, we undertook an open label, randomized controlled trial in incident patients receiving HD, with clinicians and patients blinded to bioimpedance readings in controls. A total of 439 patients with over 500 ml urine/day or residual GFR exceeding 3 ml/min/1.73m2 were recruited from 34 United Kingdom centers and randomized 1:1, stratified by center. Fluid assessments were made for up to 24 months using a standardized proforma in both groups, supplemented by availability of BI-NHW in the intervention group. Primary outcome was time to anuria, analyzed using competing-risk survival models adjusted for baseline characteristics, by intention to treat. Secondary outcomes included rate of RKF decline (mean urea and creatinine clearance), blood pressure and patient-reported outcomes. There were no group differences in cause-specific hazard rates of anuria (0.751; 95% confidence interval (0.459, 1.229)) or sub-distribution hazard rates (0.742 (0.453, 1.215)). RKF decline was markedly slower than anticipated, pooled linear rates in year 1: -0.178 (-0.196, -0.159)), year 2: -0.061 (-0.086, -0.036)) ml/min/1.73m2/month. Blood pressure and patient-reported outcomes did not differ by group. The mean difference agreement between TW and BI-NHW was similar for both groups, Bioimpedance: -0.04 kg; Control: -0.25 kg. Thus, use of a standardized clinical protocol for fluid assessment when setting TW is associated with excellent preservation of RKF. Hence, bioimpedance measurements are not necessary to achieve this.

Gut Microbiota Interventions to Retain Residual Kidney Function

Residual kidney function for patients with chronic kidney disease (CKD) is associated with better quality of life and outcome; thus, strategies should be implemented to preserve kidney function. Among the multiple causes that promote kidney damage, gut dysbiosis due to increased uremic toxin production and endotoxemia need attention. Several strategies have been proposed to modulate the gut microbiota in these patients, and diet has gained increasing attention in recent years since it is the primary driver of gut dysbiosis. In addition, medications and faecal transplantation may be valid strategies. Modifying gut microbiota composition may mitigate chronic kidney damage and preserve residual kidney function. Although various studies have shown the influential role of diet in modulating gut microbiota composition, the effects of this modulation on residual kidney function remain limited. This review discusses the role of gut microbiota metabolism on residual kidney function and vice versa and how we could preserve the residual kidney function by modulating the gut microbiota balance.

Factors Associated With Adherence to Fluid Restriction in Patients Undergoing Hemodialysis in Indonesia

BACKGROUND

The factors related to fluid intake adherence among patients undergoing hemodialysis have been explored in many studies. However, most of these were conducted in Western countries and have produced inconsistent results. A study of this issue in Indonesia, a tropical country with strong herbal medicine traditions, may show different results. In addition to demographic characteristics, self-efficacy is a standard measurement used in chronic care management activities such as hemodialysis treatment. Understanding the reasons behind patient nonadherence in Indonesia may help nurses better manage the fluid intake of patients.

PURPOSE

This study was designed to determine the factors that predict patient adherence to fluid intake restrictions.

METHODS

A cross-sectional study was conducted on 153 patients undergoing hemodialysis at two hospitals. Intradialytic weight gain over a 1-month period was recorded to assess the participants' adherence to fluid intake restrictions. Intradialytic weight gains of more than 2 kg was considered to be nonadherent. A daily urine output and level of thirst were also recorded. The participants completed an adapted self-efficacy questionnaire, Swedish Fluid Intake Appraisal Inventory, and the data were analyzed together with demographic characteristic and clinical parameters using hierarchical multiple regression.

RESULTS

The results revealed that most of the respondents did not adequately adhere to fluid intake restrictions (59.5%). Intradialytic weight gain was shown to strongly correlate with self-efficacy (p < .05, β = -.201), gender (p < .05, β = -.179), educational background (p = .05, β = .159), and urine output (p < .05, β = -.168). Demographic characteristic explained 10.6% and self-efficacy explained 3.9% of the variance in fluid adherence.

CONCLUSIONS/IMPLICATIONS FOR PRACTICE

Female participants with higher self-efficacy scores reported the lowest average level of intradialytic weight gain, indicating better adherence to fluid intake restrictions. Several demographic factors as well as self-efficacy were identified as potential predictors of fluid intake restriction adherence. Therefore, measuring self-efficacy periodically is a good initial step toward detecting those patients who are at higher risk of noncompliance with fluid intake restrictions.

Health literacy as predictors of fluid management in people receiving hemodialysis in China: A structural equation modeling analysis

OBJECTIVES

To explore the impact of health literacy (HL) on perceived benefits of fluid restriction (PBFR), self-reported fluid restriction (SRFR) and relative-interdialytic weight gain (R-IDWG) in people receiving hemodialysis (HD).

METHODS

We conducted a cross-sectional study in two nephrology departments from two hospitals in Guangzhou, China (n = 226). The HL questionnaire, PBFR Subscale of Health Belief Model Constructs and Fluid Adherence Subscale of the HD Patients Therapy Adherence Scale were used. R-IDWG was calculated by the mean IDWG (from 3 consecutive HD), divided by the dry weight.

RESULTS

In structural equation modeling, three domains of the HL questionnaire, namely Actively Managing My Health, Social Support and Actively Engaging with Healthcare Providers (HCPs), were directly and positively associated with PBFR. Higher Actively Managing My Health predicted higher SRFR both directly and indirectly. Sufficient Social Support and adequate Actively Engaging with HCPs predicted higher SRFR indirectly. All three HL domains predicted R-IDWG indirectly.

CONCLUSION

Improving patients' HL could increase their understanding of PBFR and be more apt to follow fluid restrictions and reduce R-IDWG.

PRACTICE IMPLICATIONS

A better understanding of the relationships among HL, PBFR, SRFR and R-IDWG will allow for tailored interventions to decrease R-IDWG in people receiving HD.

Parathyroid Hormone Concentrations in Maintenance Hemodialysis: Longitudinal Evaluation of Intact and Biointact Assays

RATIONALE & OBJECTIVE

Management of chronic kidney disease mineral and bone disorder requires parathyroid hormone (PTH) concentrations. "Biointact" PTH immunoassays detect "whole" PTH (wPTH), whereas "intact" immunoassays measure PTH plus PTH fragments (iPTH). We aimed to determine whether longitudinal changes in PTH concentrations can be evaluated using biointact and intact immunoassays alike.

STUDY DESIGN

Open noninterventional longitudinal cohort study.

SETTING & PARTICIPANTS

PTH concentrations were measured quarterly up to 5 times in 102 hemodialysis patients.

PREDICTORS & TESTS COMPARED

Age, sex, phosphate levels, and others as clinical predictors for PTH trend. Tests compared were iPTH immunoassays from Siemens and Roche and wPTH immunoassays from Roche and DiaSorin.

OUTCOMES

PTH concentration trend; regression equations; test bias.

ANALYTICAL APPROACH

Predictive regression-to-the-mean model for PTH slope; Bland-Altman plots, Passing-Bablok regression, and reference change values for test comparisons.

RESULTS

wPTH concentrations were similar with both immunoassays (wPTH-Roche = 11.7 + 0.97 × wPTH-DiaSorin, r = 0.99; mean ± 1.96 SD bias, 8.2 ± 43.3 pg/mL [17.5% ± 40.9%], by Bland-Altman plots). iPTH-Siemens concentrations were higher than iPTH-Roche concentrations (iPTH-Siemens = -5.4 + 1.33 × iPTH-Roche, r = 0.99; mean ± 1.96 SD bias, 84.0 ± 180.2 pg/mL [21.1% ± 29.8%], by Bland-Altman plots). iPTH-Roche and iPTH-Siemens concentrations were 2- and 2.5-fold higher than wPTH concentrations, respectively. Full agreement among all 4 immunoassays in detecting both significant and insignificant changes in PTH concentrations, upward or downward from one quarter to the next, was reached in 87% of consecutive measurements. In a predictive model, baseline PTH concentrations > 199 pg/mL (wPTH-Roche), 204 pg/mL (wPTH-DiaSorin), 386 pg/mL (iPTH-Roche), and 417 pg/mL (iPTH-Siemens) correctly predicted declining PTH concentration trend in 62% to 68% of patients, but age, sex, hemodialysis vintage, and calcium and phosphate levels were no significant predictors.

LIMITATIONS

Limited number of immunoassays, only 59 patients attended all quarterly samplings.

CONCLUSIONS

wPTH-Roche and wPTH-DiaSorin concentrations were similar, while iPTH was higher than wPTH concentrations. The iPTH-Siemens immunoassay is either higher calibrated or detects more fragments than iPTH-Roche. However, longitudinal PTH concentration changes largely coincided with all tested immunoassays.

Sodium, volume and pressure control in haemodialysis patients for improved cardiovascular outcomes

Chronic volume overload is pervasive in patients on chronic haemodialysis and substantially increases the risk of cardiovascular death. The rediscovery of the three-compartment model in sodium metabolism revolutionizes our understanding of sodium (patho-)physiology and is an effect modifier that still needs to be understood in the context of hypertension and end-stage kidney disease. Assessment of fluid overload in haemodialysis patients is central yet difficult to achieve, because traditional clinical signs of volume overload lack sensitivity and specificity. The highest all-cause mortality risk may be found in haemodialysis patients presenting with high fluid overload but low blood pressure before haemodialysis treatment. The second highest risk may be found in patients with both high blood pressure and fluid overload, while high blood pressure but normal fluid overload may only relate to moderate risk. Optimization of fluid overload in haemodialysis patients should be guided by combining the traditional clinical evaluation with objective measurements such as bioimpedance spectroscopy in assessing the risk of fluid overload. To overcome the tide of extracellular fluid, the concept of time-averaged fluid overload during the interdialytic period has been established and requires possible readjustment of a negative target post-dialysis weight. ²³Na-magnetic resonance imaging studies will help to quantitate sodium accumulation and keep prescribed haemodialytic sodium mass balance on the radar. Cluster-randomization trials (e.g. on sodium removal) are underway to improve our therapeutic approach to cardioprotective haemodialysis management.

Residual Urine Output and Mortality in a Prospective Hemodialysis Cohort

Introduction

Although residual urine output (UOP) is associated with better survival and quality of life in dialysis patients, frequent measurement by 24-hour urine collection is burdensome. We thus sought to examine the association of patients’ self-reported residual UOP, as an alternative proxy of measured residual UOP, with mortality risk in a prospective hemodialysis cohort study.

Methods

Among 670 hemodialysis patients from the prospective multicenter Malnutrition, Diet, and Racial Disparities in Kidney Disease study, we examined associations of residual UOP, ascertained by patient self-report, with all-cause mortality. Patients underwent protocolized surveys assessing presence and frequency of UOP (absent, every 1–3 days, >1 time per day) every 6 months from 2011 to 2015. We examined associations of baseline and time-varying UOP with mortality using Cox regression.

Results

In analyses of baseline UOP, absence of UOP was associated with higher mortality in expanded case-mix adjusted Cox models (ref: presence of UOP): hazard ratio (HR), 1.78 (95% confidence interval [CI], 1.16–2.72). In analyses examining baseline frequency of UOP, point estimates suggested a graded association between lower frequency of UOP and higher mortality, although estimates for UOP every 1 to 3 days did not reach statistical significance (reference: UOP >1 time per day): HR, 1.29 (95% CI, 0.82–2.05) and HR, 1.97 (95% CI, 1.24–3.12) for UOP every 1 to 3 days and absence of UOP, respectively. Similar findings were observed in analyses of time-varying UOP.

Conclusion

In hemodialysis patients, there is a graded association between lower frequency of self-reported UOP and higher mortality. Further studies are needed to determine the clinical impact of more frequent assessment of residual UOP using self-reported methods.

Blood pressure and volume management in dialysis: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Blood pressure (BP) and volume control are critical components of dialysis care and have substantial impacts on patient symptoms, quality of life, and cardiovascular complications. Yet, developing consensus best practices for BP and volume control have been challenging, given the absence of objective measures of extracellular volume status and the lack of high-quality evidence for many therapeutic interventions. In February of 2019, Kidney Disease: Improving Global Outcomes (KDIGO) held a Controversies Conference titled Blood Pressure and Volume Management in Dialysis to assess the current state of knowledge related to BP and volume management and identify opportunities to improve clinical and patient-reported outcomes among individuals receiving maintenance dialysis. Four major topics were addressed: BP measurement, BP targets, and pharmacologic management of suboptimal BP; dialysis prescriptions as they relate to BP and volume; extracellular volume assessment and management with a focus on technology-based solutions; and volume-related patient symptoms and experiences. The overarching theme resulting from presentations and discussions was that managing BP and volume in dialysis involves weighing multiple clinical factors and risk considerations as well as patient lifestyle and preferences, all within a narrow therapeutic window for avoiding acute or chronic volume-related complications. Striking this challenging balance requires individualizing the dialysis prescription by incorporating comorbid health conditions, treatment hemodynamic patterns, clinical judgment, and patient preferences into decision-making, all within local resource constraints.