Kt/V: achievement, predictors and relationship to mortality in hemodialysis patients in the Gulf Cooperation Council countries: results from DOPPS (2012-18)

Research progress on measurement methods and evaluation of the hemodialysis adequacy index Kt/V

The most common form of replacement therapy for end-stage renal disease (ESRD) is hemodialysis, and the adequacy of hemodialysis is strongly associated with the quality of life and long-term survival of patients. Kt/V is currently one of the most important indicators for evaluating the adequacy of hemodialysis. There are many methods for measuring Kt/V, such as blood collection and measurement, dialysate measurement, bioresistive resistance, WinNonlin software analysis, and artificial intelligence. There are different views on the importance of Kt/V as an indicator of the adequacy of hemodialysis. This article provides a literature review of the various methods of measuring Kt/V and on different perspectives on Kt/V as an evaluation of hemodialysis adequacy.

Care for end-stage kidney disease in China: progress, challenges, and recommendations

This review comprehensively evaluates China's progress in care of end-stage kidney disease (ESKD) by identifying achievements and gaps, reviewing ESKD-related policy initiatives, and proposing policy recommendations. In the past decade, China has made laudable progress in access to ESKD care with narrowed difference between the number of patients needing and receiving kidney replacement therapies (KRT). China has also experienced significant improvements in clinical quality and outcomes of ESKD care. These achievements stem from concerted efforts in advocating effective policies, increasing fiscal subsidies, re-designing health insurance schemes, encouraging healthcare delivery from both public and private sectors, and improving quality regulation. However, challenges remain, including inequitable access to care across regions and groups, and suboptimal quality and outcomes in some underdeveloped areas. To address these gaps, we recommend reforming the financing policy, adopting quality-based payment methods, strengthening quality monitoring system, improving chronic kidney disease prevention and management, and developing alternative KRT modalities.

Relationship between effective blood flow rate and clinical outcomes in maintenance hemodialysis patients: a single-center study

The association between blood flow rate (BFR) and clinical outcomes in patients undergoing maintenance hemodialysis (MHD) is inconclusive. This retrospective study included 175 patients undergoing MHD treatment between July 2015 and March 2022, divided into two groups based on time-averaged effective blood flow rate (eBFR) median value. We investigated arteriovenous fistula (AVF) outcomes and the association of eBFR with all-cause mortality and new major adverse cardiovascular events (MACE). Mean ± SD and median time-averaged eBFR values were 276 ± 24 and 275 mL/min, respectively. After adjusting for relevant factors including age, sex, vintage, diabetes, CVD, receiving hemodiafiltration (HDF) treatment and spKt/V, Cox models indicated a low time-averaged eBFR (≤ 275 ml/min) was associated with increased risks of all-cause mortality (hazard ratio [HR] 14.18; 95% confidence interval [CI], 3.14-64.1) and new MACE (HR 3.76; 95% CI, 1.91-7.40) in MHD patients. Continuous Cox models demonstrated each 20 ml/min increase in eBFR linked to a 63% decrease in the risk of all-cause mortality (HR: 0.37, 95% CI: 0.23-0.59) and a 38% decrease in the occurrence of new MACE (HR: 0.62, 95% CI: 0.46-0.84). There was no significant difference in AVF outcomes between the two groups. Our study noted higher eBFR (>275 mL/min) is associated with lower risks of both all-cause mortality and new MACE compared with low eBFR (≤275 mL/min). Increased eBFR is not associated with a higher risk of AVF failure.

Progress of nations in the organisation of, and structures for, kidney care delivery between 2019 and 2023: cross sectional survey in 148 countries

OBJECTIVE

To assess changes in key measures of kidney care using data reported in 2019 and 2023.

DESIGN

Cross sectional survey in 148 countries.

SETTING

Surveys from International Society of Nephrology Global Kidney Health Atlas between 2019 and 2023 that included participants from countries in Africa (n=36), Eastern and Central Europe (n=16), Latin America (n=18), the Middle East (n=11), Newly Independent States and Russia (n=10), North America and the Caribbean (n=8), North and East Asia (n=6), Oceania and South East Asia (n=15), South Asia (n=7), and Western Europe (n=21).

PARTICIPANTS

Countries that participated in both surveys (2019 and 2023).

MAIN OUTCOME MEASURES

Comparison of 2019 and 2023 data for availability of kidney replacement treatment services, access, health financing, workforce, registries, and policies for kidney care. Data for countries that participated in both surveys (2019 and 2023) were included in our analysis. Country data were aggregated by International Society of Nephrology regions and World Bank income levels. Proportionate changes in the status of these measures across both periods were reported.

RESULTS

Data for 148 countries that participated in both surveys were available for analysis. The proportions of countries that provided public funding (free at point of delivery) increased from 27% in 2019 to 28% in 2023 for haemodialysis, 23% to 28% for peritoneal dialysis, and 31% to 36% for kidney transplantation services. Centres for these treatments increased from 4.4 per million population (pmp) to 4.8 pmp (P<0.001) for haemodialysis, 1.4 pmp to 1.6 pmp for peritoneal dialysis, and 0.43 pmp to 0.46 pmp for kidney transplantation services. Overall, access to haemodialysis and peritoneal dialysis improved, however, access to kidney transplantation decreased from 30 pmp to 29 pmp. The global median prevalence of nephrologists increased from 9.5 pmp to 12.4 pmp (P<0.001). Changes in the availability of kidney registries and in national policies and strategies for kidney care were variable across regions and country income levels. The reporting of specific barriers to optimal kidney care by countries increased from 55% to 59% for geographical factors, 58% to 68% (P=0.043) for availability of nephrologists, and 46% to 52% for political factors.

CONCLUSIONS

Important changes in key areas of kidney care delivery were noted across both periods globally. These changes effected the availability of, and access to, kidney transplantation services. Countries and regions need to enact enabling strategies for preserving access to kidney care services, particularly kidney transplantation.

KRT in Brazil: A Retrospective Cohort Study Based on Analysis of the Brazilian Public Health System

Key Points

A large comprehensive analysis of patients undergoing KRT within Brazil's Public Health System from 2015 to 2023. We reported an increase in the age at which dialysis began and a decline in the adoption of peritoneal dialysis over the years. We showed better hemodialysis adequacy as measured by single-pool Kt/V.

Background

Brazil has the largest public health system providing universal coverage for chronic dialysis. The objective was to describe the number, sociodemographic, and clinical characteristics of patients undergoing KRT by dialysis within the public health system in Brazil.

Methods

We carried out a retrospective cohort study analyzing the database from the Brazilian Public Health System, focusing on procedures related to KRT. The study encompassed both prevalent and incident patients who underwent KRT in Brazil between 2015 and 2023.

Results

We observed an increase in the number and prevalence rate of dialysis patients from 2015 to 2023. We also noticed an increase in the age at dialysis initiation and in the prevalence of mixed-race patients and a reduction in the proportion of those undergoing peritoneal dialysis and with arteriovenous fistula. We identified an upward trajectory in the values of single-pool Kt/V over the years, contrasting with a decline in hemoglobin levels. The overall estimated prevalence rate of dialysis patients increased from 654 per million population (pmp) to 792 pmp over the years. The survival rates of incident patients undergoing KRT at 12 and 96 months were 81% and 60%, respectively.

Conclusions

We reported an increase in the age at which dialysis began and a decline in the adoption of peritoneal dialysis over the years. Although there have been some improvements over the years resulting in better adequacy of hemodialysis as measured by Kt/V, controlling certain parameters, such as hemoglobin levels, has remained challenging.

Effects of Kt/Vurea on outcomes according to age in patients on maintenance hemodialysis

Background

The guidelines recommended target and minimum single-pool Kt/Vurea are 1.4 and 1.2, respectively, in hemodialysis patients. However, the optimal hemodialysis dose remains controversial. We investigated the effects of Kt/Vurea on patient outcomes according to age, with a focus on older patients.

Methods

This study used the hemodialysis quality assessment program and claims datasets. Patients were divided into four subgroups according to age (<65, 65-74, 75-84, and ≥85 years). Each group was divided into three subgroups according to Kt/Vurea : reference (ref) (1.2 ≤ Kt/Vurea ≤ 1.4), low (< 1.2), and high (> 1.4).

Results

The low, ref, and high Kt/Vurea groups included 1668, 8156, and 16 546 (< 65 years); 474, 3058, and 7646 (65-74 years); 225, 1362, and 4194 (75-84 years); and 14, 126, and 455 (≥85 years) patients, respectively. The low Kt/Vurea group had higher mortality rates than the ref Kt/Vurea group irrespective of age [adjusted hazard ratio (aHR), 95% confidence interval (CI): 1.23, 1.11-1.36; 1.14, 1.00-1.30; 1.28, 1.09-1.52; and 2.10, 1.16-3.98, in patients aged <65, 65-74, 75-84, and ≥85 years, respectively]. The high Kt/Vurea group had lower mortality rates than the ref Kt/Vurea group in patients aged <65 and 65-74 years (aHR, 95% Cl: 0.87, 0.82-0.92 and 0.93, 0.87-0.99 in patients aged <65 and 65-74 years, respectively).

Conclusions

These results support the current recommendations of a minimum Kt/Vurea of 1.2 even in patients age ≥85 years. In young patients, Kt/Vurea above the recommended threshold can be beneficial for survival.

Bacteremia and Mortality among Patients with Nontunneled and Tunneled Catheters for Hemodialysis

Introduction

Central venous catheters for hemodialysis (HD) can be nontunneled catheters (NTC) or tunneled catheters (TC). Bacteremia and dysfunction are complications that can impact morbidity and mortality. We decided to compare the rates of bacteremia and dysfunction between NTC and TC and patient survival 90 days after catheter insertion.

Methods

Retrospective cohort to evaluate catheters inserted between January 2011 and December 2020 in a tertiary hospital. Catheters in patients with end-stage chronic kidney disease were included. Patients with acute kidney injury, catheters that lasted less than three HD sessions, and patients who died within one week after insertion were excluded. Bacteremia and dysfunction rates, bacteremia-free survival, and dysfunction-free survival were investigated. Multivariable analysis was performed using a Cox proportional hazards regression model for patient survival at 90 days.

Results

670 catheters were analyzed in 287 patients, 422 NTC (63%), and 248 TC (37%). The rates of confirmed bacteremia per 1,000 catheter-days were 1.19 for NTC and 0.20 for TC (p < 0.0001). The confirmed or possible bacteremia rates were 2.27 and 0.37 per 1,000 catheter-days for NTC and TC, respectively (p < 0.0001). The dysfunction rates were 3.96 and 0.86 for NTC and TC, respectively (p < 0.0001). Patient survival at 90 days was higher in the TC group than the NTC group (96.8% vs. 89.1%; p < 0.0001).

Conclusion

We found lower rates of bacteremia and dysfunction for TC and demonstrated that using NTC affects patient mortality.

The prognostic value of URR equals that of Kt/V for all-cause mortality in Taiwan after 10-year follow-up

Kt/V and URR (urea reduction ratio) measurements represent dialysis adequacy. Single-pool Kt/V is theoretically a superior method and is recommended by the Kidney Disease Outcomes Quality Initiative guidelines. However, the prognostic value of URR compared with Kt/V for all-cause mortality is unknown. The effect modifiers and cut-off values of the two parameters have not been compared. We investigated 2615 incident hemodialysis patients with URR of 72% and Kt/V (Daugirdas) of 1.6. The average patient age was 59 years, 50.7% were female, and 1113 (40.2%) died within 10 years. URR and Kt/V were both positively associated with nutrition factors and female sex and negatively associated with body weight and heart failure. In Cox regression mod-els for all-cause mortality, the hazard ratios (HRs) of high URR groups (65-70%, 70-75%, and > 75%) and the URR < 65% group were 0.748 (0.623-0.898), 0.693 (0.578-0.829), and 0.640 (0.519-0.788), respectively. The HRs of high Kt/V groups (Kt/V 1.2-1.4, 1.4-1.7, and > 1.7) and the Kt/V < 1.2 group were 0.711 (0.580-0.873), 0.656 (0.540-0.799), and 0.623 (0.498-0.779), respec-tively. In subgroup analysis, Kt/V was not associated with all-cause mortality in women. The prognostic value of URR for all-cause mortality is as great as that of Kt/V. URR > 70% and Kt/V > 1.4 were associated with a higher survival rate. Kt/V may have weaker prognostic value for women.

Pruritus in Chronic Kidney Disease: An Update

Chronic kidney disease-associated pruritus (CKDaP) is an often under-diagnosed and under-recognized condition, despite its considerable prevalence within the chronic kidney disease (CKD) population. Universally accepted guidelines are also lacking. The true prevalence of CKDaP worldwide therefore remains unknown, although its negative impact on mortality and health-related quality of life outcomes is very clear. The pathophysiological mechanisms leading to the onset of CKDaP are only partly understood. CKDaP is currently believed to be caused by a multifactorial process, from local skin changes, metabolic alterations, the development of neuropathy and dysregulation of opioid pathways, and psychological factors. Much work has been carried out towards a more systematic and structured approach to clinical diagnosis. Various tools are now available to assess the severity of CKDaP. Many of these tools require greater validation before they can be incorporated into the guidelines and into routine clinical practice. Further efforts are also needed in order to increase the awareness of clinicians and patients so that they can identify the CKDaP signs and symptoms in a timely manner. Currently established treatment options for CKDaP focus on the prevention of xerosis via topical emollients, the optimization of dialysis management, early referral to kidney transplantation if appropriate, oral antihistamine, and a variety of neuropathic agents. Other novel treatment options include the following: topical analgesics, topical tacrolimus, cannabinoid-containing compounds, antidepressants, oral leukotrienes, opioids, and non-pharmacological alternative therapies (i.e., phototherapy, dietary supplements, acupuncture/acupressure). We provide an updated review on the evidence relating to the epidemiology, the pathophysiology, the clinical assessment and diagnosis, and the management of CKDaP.

The association between dose of hemodialysis and patients mortality in a prospective cohort study

Dialysis adequacy is a known risk factor for mortality in maintenance hemodialysis (MHD) patients. However, the optimal dialysis dose remains controversial. Therefore, we aimed to explore the relationship between dialysis dose and all-cause and cardiovascular disease (CVD) mortality among MHD. We examined the associations of dialysis dose with mortality in a cohort (n = 558) of MHD patients from 31 December 2015 to 31 December 2020. Dialysis adequacy was assessed using baseline Single-pool Kt/Vurea (spKt/V), which was categorized into three groups, and the lowest dose group was used as the reference category. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazards regression models. A total of 214 patients died (64.5% for CVD). Compared with the low-dose group, high-dose group could reduce the risk of all-cause mortality by 33% (HR = 0.67, 95% CI: 0.47-0.98). Of note, when stratification by age, high-dose group was associated with both lower all-cause (HR = 0.46, 95% CI: 0.26-0.81) and CVD mortality (HR = 0.42, 95% CI: 0.20-0.88) among patients with age below 65 years. When stratification by dialysis age, high-dose group was associated with decreased risk of CVD mortality (HR = 0.43, 95% CI: 0.20-0.91) among patients with dialysis age over 60 months. spKt/V is a simple index of hemodialysis dose used in clinical practice and a useful modifiable factor in predicting the risk of death, especially in MHD patients under 65 years old or dialysis age more than 60 months.

Hemodiafiltration in developing countries

Hemodiafiltration (HDF) is a promising kidney replacement therapy modality for patients with end-stage kidney disease. The principle of uremic toxin clearance by combining convection and diffusion can lead to greater benefits compared to conventional hemodialysis. Evidence is building that supports the advantages of HDF with short-term outcomes such as greater intradialytic hemodynamic stability, improved nutritional status, attenuation of anemia, and reduction of inflammatory cytokines which produce improved key long-term impacts including survival and cardiovascular outcomes. Very little is known about the prevalence of HDF treatments in developing countries due to a shortage of national kidney registries. HDF experience is limited in many countries due to the cost of dialysis treatments, availability of online HDF machines, and reimbursement policies. These obstacles have led to nephrologists developing innovations, for example, convective control HDF (CC-HDF), simple mid-dilution, and simple mixed-dilution methods, which may be as effective as commercially available HDF machines. In this article, we will focus on the experience of HDF practice and barriers to adoption in developing countries. Results can guide clinical practice recommendations for implementing HDF in resource-limited settings.

Global real-world data on hemodiafiltration: An opportunity to complement clinical trial evidence

Hemodiafiltration (HDF) is a renal replacement therapy that utilizes both diffusive clearance and convective transport to achieve greater clearance of middle-molecular-weight solutes. Among other factors, important prerequisites for the implementation of HDF include access to high-flux dialyzers, achievement of high blood flow rates, and availability of high volumes of sterile substitution/replacement fluids. Online hemodiafiltration (OL-HDF) is an established kidney replacement therapy, frequently used in many countries. Although in the United States, some prerequisites (e.g., access to high-flux dialyzers and achievement of high blood flow rates) for OL-HDF treatment are readily available; however, a machine capable of generating the online solution for OL-HDF is currently not available. As the clinical experience with HDF accumulates globally, it is worth examining the evidence for this kidney replacement therapy as used in routine clinical care. Such real-world evidence is increasingly recognized as valuable by clinicians and may inform regulatory decisions. In this review, we will focus on emerging global real-world data derived from routine clinical practices and examine how these data may complement those derived from clinical trials.

Blood flow rate: An independent risk factor of mortality in Chinese hemodialysis patients

BACKGROUND

Studies suggested the association between blood flow rate (BFR) and mortality might be beyond dialysis adequacy. This study aimed to explore if BFR is an independent predictor of clinical outcomes in Chinese hemodialysis (HD) patients.

METHODS

This study included data from patients in China Dialysis Outcomes and Practice Patterns Study (DOPPS) Phase 5. Patients with a record of BFR were included, and demographic data, comorbidities, hospitalization, and death records were collected. Associations between BFR and all-cause mortality and hospitalization were analyzed using Cox regression models.

RESULTS

One thousand four hundred twelve (98.9%) patients were included. Most patients were with BFR < 300 ml/min. After full adjustment, each 10-ml/min increase of BFR was associated with a 6.4% decrease in all-cause mortality risk (HR: 0.936, 95% CI: 0.880-0.996) but not first hospitalization (HR: 0.987, 95% CI: 0.949-1.027). The impact of BFR on mortality may be more prominent in patients who were male gender, nondiabetic, albumin < 4.0 g/dl, and hemoglobin ≥ 9.0 g/dl.

CONCLUSION

Increased BFR is independently associated with a lower risk of all-cause mortality within the range of BFR 200-300 ml/min. And this effect is more pronounced in patients who were male gender, nondiabetic, albumin < 4.0 g/dl, and hemoglobin ≥ 9.0 g/dl.

Global Epidemiology of End-Stage Kidney Disease and Disparities in Kidney Replacement Therapy

BACKGROUND

The global epidemiology of end-stage kidney disease (ESKD) reflects each nation's unique genetic, environmental, lifestyle, and sociodemographic characteristics. The response to ESKD, particularly regarding kidney replacement therapy (KRT), depends on local disease burden, culture, and socioeconomics. Here, we explore geographic variation and global trends in ESKD incidence and prevalence and examine variations in KRT modality, practice patterns, and mortality. We conclude with a discussion on disparities in access to KRT and strategies to reduce ESKD global burden and to improve access to treatment in low- and middle-income countries (LMICs).

SUMMARY

From 2003 to 2016, incidence rates of treated ESKD were relatively stable in many higher income countries but rose substantially predominantly in East and Southeast Asia. The prevalence of treated ESKD has increased worldwide, likely due to improving ESKD survival, population demographic shifts, higher prevalence of ESKD risk factors, and increasing KRT access in countries with growing economies. Unadjusted 5-year survival of ESKD patients on KRT was 41% in the USA, 48% in Europe, and 60% in Japan. Dialysis is the predominant KRT in most countries, with hemodialysis being the most common modality. Variations in dialysis practice patterns account for some of the differences in survival outcomes globally. Worldwide, there is a greater prevalence of KRT at higher income levels, and the number of people who die prematurely because of lack of KRT access is estimated at up to 3 times higher than the number who receive treatment. Key Messages: Many people worldwide in need of KRT as a life-sustaining treatment do not receive it, mostly in LMICs where health care resources are severely limited. This large treatment gap demands a focus on population-based prevention strategies and development of affordable and cost-effective KRT. Achieving global equity in KRT access will require concerted efforts in advocating effective public policy, health care delivery, workforce capacity, education, research, and support from the government, private sector, nongovernmental, and professional organizations.

Renal Data from the Arab World Dialysis in Kuwait: 2013-2019

The total number of end-stage kidney disease patients treated with dialysis in 2019 in Kuwait was 2230, with a 6% increase from the year before. Dialysis prevalence was 465 per million population (PMP) and dialysis incidence was100 PMP. Kuwaiti nationals represented 70% of the dialysis population and males represented 52%. Of the same population, 59% had diabetes. Hepatitis C virus affected <4% and hepatitis B virus affected <2% of the dialysis population. The annual mortality rate was stable at around 12%. Hemodialysis (HD) share was 89%, with 48% of HD patients getting HD via catheter, 54% on hemodiafiltration (HDF), and 50% dialyzing against a calcium bath of 1.75. Patients getting <3 times/week of HD constituted 10% and patients spending <3.5 h/session constituted 11%. We had only 20 dialysis patients under the age of 12 years (12 on HD). The major challenges faced included poor peritoneal dialysis penetration, the unacceptable high rates of catheters as primary HD vascular access, partly due to lack of chronic kidney disease (CKD) clinics and lack of vascular access coordinators, and the unexplained high rates of use of calcium bath of 1.75. There is also a need for a national campaign for early detection and prevention of CKD to reduce rates of end-stage renal disease.