A stepped wedge cluster randomized trial of graphical surveillance of kidney function data to reduce late presentation for kidney replacement therapy.

Late presentation for kidney replacement therapy (KRT) is an important cause of avoidable morbidity and mortality. Here, we evaluated the effect of a complex intervention of graphical estimated glomerular filtration rate (eGFR) surveillance across 15% of the United Kingdom population on the rate of late presentation using data routinely collected by the United Kingdom Renal Registry. A stepped wedge cluster randomized trial was established across 19 sites with eGFR graphs generated from all routine blood tests (community and hospital) across the population served by each site. Graphs were reviewed by trained laboratory or clinical staff and high-risk graphs reported to family doctors. Due to delays outside the control of clinicians and researchers few laboratories activated the intervention in their randomly assigned time period, so the trial was converted to a quasi-experimental design. We studied 6,100 kidney failure events at 20 laboratories served by 17 main kidney units. A total of 63,981 graphs were sent out. After adjustment for calendar time there was no significant reduction in the rate of presentation during the intervention period. Therefore, implementation of eGFR graph surveillance did not reduce the rate of late presentation for KRT after adjustment for secular trends. Thus, graphical surveillance is an intervention aimed at reducing late presentation, but more evidence is required before adoption of this strategy can be recommended.

Organization and Structures for Detection and Monitoring of CKD Across World Countries and Regions: Observational Data From a Global Survey.

RATIONALE & OBJECTIVE: Established therapeutic interventions effectively mitigate the risk and progression of chronic kidney disease (CKD). Countries and regions have a compelling need for organizational structures that enable early identification of people with CKD who can benefit from these proven interventions. We report the current global status of CKD detection programs. STUDY DESIGN: A multinational cross-sectional survey. SETTING & PARTICIPANTS: Stakeholders, including nephrologist leaders, policymakers, and patient advocates from 167 countries, participating in the International Society of Nephrology (ISN) survey from June to September 2022. OUTCOME: Structures for the detection and monitoring of CKD, including CKD surveillance systems in the form of registries, community-based detection programs, case-finding practices, and availability of measurement tools for risk identification. ANALYTICAL APPROACH: Descriptive statistics. RESULTS: Of all participating countries, 19% (n=31) reported CKD registries, and 25% (n=40) reported implementing CKD detection programs as part of their national policies. There were variations in CKD detection program, with 50% (n=20) using a reactive approach (managing cases as identified) and 50% (n=20) actively pursuing case-finding in at-risk populations. Routine case-finding for CKD in high-risk populations was widespread, particularly for diabetes (n=152; 91%) and hypertension (n=148; 89%). Access to diagnostic tools, estimated glomerular filtration rate (eGFR), and urine albumin-creatinine ratio (UACR) was limited, especially in low-income (LICs) and lower-middle-income (LMICs) countries, at primary (eGFR: LICs 22%, LMICs 39%, UACR: LICs 28%, LMICs 39%) and secondary/tertiary health care levels (eGFR: LICs 39%, LMICs 73%, UACR: LICs 44%, LMICs 70%), potentially hindering CKD detection. LIMITATIONS: A lack of detailed data prevented an in-depth analysis. CONCLUSIONS: This comprehensive survey highlights a global heterogeneity in the organization and structures (surveillance systems and detection programs and tools) for early identification of CKD. Ongoing efforts should be geared toward bridging such disparities to optimally prevent the onset and progression of CKD and its complications. PLAIN-LANGUAGE SUMMARY: Early detection and management of chronic kidney disease (CKD) is crucial to prevent progression to kidney failure. A multinational survey across 167 countries revealed disparities in CKD detection programs. Only 19% reported CKD registries, and 25% implemented detection programs as part of their national policy. Half used a reactive approach while others actively pursued case-finding in at-risk populations. Routine case-finding was common for individuals with diabetes and hypertension. However, limited access to gold standard tools such as estimated glomerular filtration rate (eGFR) and urine albumin-creatinine ratio (UACR), especially in low-income and lower-middle income countries, may hinder CKD detection. A global effort to bridge these disparities is needed to optimally prevent the onset and progression of CKD and its complications.

Global access and quality of conservative kidney management.

BACKGROUND: Conservative kidney management (CKM) describes supportive care for people living with kidney failure who choose not to receive or are unable to access kidney replacement therapy (KRT). This study captured the global availability of CKM services and funding. METHODS: Data came from the International Society of Nephrology Global Kidney Health survey conducted between June and September 2022. Availability of CKM, infrastructure, guidelines, medications and training were evaluated. RESULTS: CKM was available in some form in 61% of the 165 responding countries. CKM chosen through shared decision-making was available in 53%. Choice-restricted CKM-for those unable to access KRT-was available in 39%. Infrastructure to provide CKM chosen through shared decision-making was associated with national income level, reported as being "generally available" in most healthcare settings for 71% of high-income countries, 50% of upper-middle-income countries, 33% of lower-middle-income countries and 42% of low-income countries. For choice-restricted CKM, these figures were 29%, 50%, 67% and 58%, respectively. Essential medications for pain and palliative care were available in just over half of the countries, highly dependent upon income setting. Training for caregivers in symptom management in CKM was available in approximately a third of countries. CONCLUSIONS: Most countries report some capacity for CKM. However, there is considerable variability in terms of how CKM is defined, as well as what and how much care is provided. Poor access to CKM perpetuates unmet palliative care needs, and must be addressed, particularly in low-resource settings where death from untreated kidney failure is common.

A global overview of health system financing and available infrastructure and oversight for kidney care.

BACKGROUND: Governance, health financing, and service delivery are critical elements of health systems for provision of robust and sustainable chronic disease care. We leveraged the third iteration of the International Society of Nephrology Global Kidney Health Atlas (ISN-GKHA) to evaluate oversight and financing for kidney care worldwide. METHODS: A survey was administered to stakeholders from countries affiliated with the ISN from July to September 2022. We evaluated funding models utilized for reimbursement of medications, services for the management of chronic kidney disease, and provision of kidney replacement therapy (KRT). We also assessed oversight structures for the delivery of kidney care. RESULTS: Overall, 167 of the 192 countries and territories contacted responded to the survey, representing 97.4% of the global population. High-income countries tended to use public funding to reimburse all categories of kidney care in comparison with low-income countries (LICs) and lower-middle income countries (LMICs). In countries where public funding for KRT was available, 78% provided universal health coverage. The proportion of countries that used public funding to fully reimburse care varied for non-dialysis chronic kidney disease (27%), dialysis for acute kidney injury (either hemodialysis or peritoneal dialysis) (44%), chronic hemodialysis (45%), chronic peritoneal dialysis (42%), and kidney transplant medications (36%). Oversight for kidney care was provided at a national level in 63% of countries, and at a state/provincial level in 28% of countries. CONCLUSION: This study demonstrated significant gaps in universal care coverage, and in oversight and financing structures for kidney care, particularly in in LICs and LMICs.

Worldwide organization and structures for kidney transplantation services.

BACKGROUND: Kidney transplantation (KT) is the preferred modality of kidney replacement therapy with better patient outcomes and quality of life compared with dialytic therapies. This study aims to evaluate the epidemiology, accessibility and availability of KT services in countries and regions around the world. METHODS: This study relied on data from an international survey of relevant stakeholders (clinicians, policymakers and patient advocates) from countries affiliated with the International Society of Nephrology that was conducted from July to September 2022. Survey questions related to the availability, access, donor type and cost of KT. RESULTS: In total, 167 countries responded to the survey. KT services were available in 70% of all countries, including 86% of high-income countries, but only 21% of low-income countries. In 80% of countries, access to KT was greater in adults than in children. The median global prevalence of KT was 279.0 [interquartile range (IQR) 58.0-492.0] per million people (pmp) and the median global incidence was 12.2 (IQR 3.0-27.8) pmp. Pre-emptive KT remained exclusive to high- and upper-middle-income countries, and living donor KT was the only available modality for KT in low-income countries. The median cost of the first year of KT was $26 903 USD and varied 1000-fold between the most and least expensive countries. CONCLUSION: The availability, access and affordability of KT services, especially in low-income countries, remain limited. There is an exigent need to identify strategies to ensure equitable access to KT services for people with kidney failure worldwide, especially in the low-income countries.

Global data monitoring systems and early identification for kidney diseases.

BACKGROUND: Data monitoring and surveillance systems are the cornerstone for governance and regulation, planning, and policy development for chronic disease care. Our study aims to evaluate health systems capacity for data monitoring and surveillance for kidney care. METHODS: We leveraged data from the third iteration of the International Society of Nephrology Global Kidney Health Atlas (ISN-GKHA), an international survey of stakeholders (clinicians, policymakers and patient advocates) from 167 countries conducted between July and September 2022. ISN-GKHA contains data on availability and types of kidney registries, the spectrum of their coverage, as well as data on national policies for kidney disease identification. RESULTS: Overall, 167 countries responded to the survey, representing 97.4% of the global population. Information systems in forms of registries for dialysis care were available in 63% (n = 102/162) of countries, followed by kidney transplant registries (58%; n = 94/162), and registries for non-dialysis chronic kidney disease (19%; n = 31/162) and acute kidney injury (9%; n = 14/162). Participation in dialysis registries was mandatory in 57% (n = 58) of countries; however, in more than half of countries in Africa (58%; n = 7), Eastern and Central Europe (67%; n = 10), and South Asia (100%; n = 2), participation was voluntary. The least-reported performance measures in dialysis registries were hospitalization (36%; n = 37) and quality of life (24%; n = 24). CONCLUSIONS: The variability of health information systems and early identification systems for kidney disease across countries and world regions warrants a global framework for prioritizing the development of these systems.

A global assessment of kidney care workforce.

BACKGROUND: An adequate workforce is needed to guarantee optimal kidney care. We used the International Society of Nephrology Global Kidney Health Atlas (ISN-GKHA) to provide an assessment of the global kidney care workforce. METHODS: We conducted a multinational cross-sectional survey to evaluate the global capacity of kidney care and assessed data on the number of adult and paediatric nephrologists, the number of trainees in nephrology and shortages of various cadres of the workforce for kidney care. Data are presented according to the ISN region and World Bank income categories. RESULTS: Overall, stakeholders from 167 countries responded to the survey. The median global prevalence of nephrologists was 11.75 per million population (pmp) (interquartile range [IQR] 1.78-24.76). Four regions had median nephrologist prevalences below the global median: Africa (1.12 pmp), South Asia (1.81 pmp), Oceania and Southeast Asia (3.18 pmp) and newly independent states and Russia (9.78 pmp). The overall prevalence of paediatric nephrologists was 0.69 pmp (IQR 0.03-1.78), while overall nephrology trainee prevalence was 1.15 pmp (IQR 0.18-3.81), with significant variations across both regions and World Bank income groups. More than half of the countries reported shortages of transplant surgeons (65%), nephrologists (64%), vascular access coordinators (59%), dialysis nurses (58%) and interventional radiologists (54%), with severe shortages reported in low- and lower-middle-income countries. CONCLUSIONS: There are significant limitations in the available kidney care workforce in large parts of the world. To ensure the delivery of optimal kidney care worldwide, it is essential to develop national and international strategies and training capacity to address workforce shortages.

Global structures, practices, and tools for provision of chronic peritoneal dialysis.

BACKGROUND: Worldwide, the uptake of peritoneal dialysis (PD) compared with hemodialysis remains limited. This study assessed organizational structures, availability, accessibility, affordability and quality of PD worldwide. METHODS: This cross-sectional study relied on data from kidney registries as well as survey data from stakeholders (clinicians, policymakers and advocates for people living with kidney disease) from countries affiliated with the International Society of Nephrology (ISN) from July to September 2022. RESULTS: Overall, 167 countries participated in the survey. PD was available in 79% of countries with a median global prevalence of 21.0 [interquartile range (IQR) 1.5-62.4] per million population (pmp). High-income countries (HICs) had an 80-fold higher prevalence of PD than low-income countries (LICs) (56.2 pmp vs 0.7 pmp). In 53% of countries, adults had greater PD access than children. Only 29% of countries used public funding (and free) reimbursement for PD with Oceania and South East Asia (6%), Africa (10%) and South Asia (14%) having the lowest proportions of countries in this category. Overall, the annual median cost of PD was US$18 959.2 (IQR US$10 891.4-US$31 013.8) with full private out-of-pocket payment in 4% of countries and the highest median cost in LICs (US$30 064.4) compared with other country income levels (e.g. HICs US$27 206.0). CONCLUSIONS: Ongoing large gaps and variability in the availability, access and affordability of PD across countries and world regions were observed. Of note, there is significant inequity in access to PD by children and for people in LICs.

Global structures, practices, and tools for provision of hemodialysis.

BACKGROUND: Hemodialysis (HD) is the most commonly utilized modality for kidney replacement therapy worldwide. This study assesses the organizational structures, availability, accessibility, affordability and quality of HD care worldwide. METHODS: This cross-sectional study relied on desk research data as well as survey data from stakeholders (clinicians, policymakers and patient advocates) from countries affiliated with the International Society of Nephrology from July to September 2022. RESULTS: Overall, 167 countries or jurisdictions participated in the survey. In-center HD was available in 98% of countries with a median global prevalence of 322.7 [interquartile range (IQR) 76.3-648.8] per million population (pmp), ranging from 12.2 (IQR 3.9-103.0) pmp in Africa to 1575 (IQR 282.2-2106.8) pmp in North and East Asia. Overall, home HD was available in 30% of countries, mostly in countries of Western Europe (82%). In 74% of countries, more than half of people with kidney failure were able to access HD. HD centers increased with increasing country income levels from 0.31 pmp in low-income countries to 9.31 pmp in high-income countries. Overall, the annual cost of in-center HD was US$19 380.3 (IQR 11 817.6-38 005.4), and was highest in North America and the Caribbean (US$39 825.9) and lowest in South Asia (US$4310.2). In 19% of countries, HD services could not be accessed by children. CONCLUSIONS: This study shows significant variations that have remained consistent over the years in availability, access and affordability of HD across countries with severe limitations in lower-resourced countries.

The safety of a low protein diet in older adults with advanced chronic kidney disease.

BACKGROUND: A low protein diet (LPD) is recommended to patients with advanced chronic kidney disease (CKD), whereas geriatric guidelines recommend a higher amount of protein. The aim of this study was to evaluate the safety of LPD treatment in older adults with advanced CKD. METHODS: The EQUAL study is a prospective, observational study, including patients ≥65 years, incident estimated glomerular filtration rate <20 ml/min/1.73m², in six European countries with follow-up up till six years. Nutritional status was assessed by 7-point subjective global assessment (SGA) every 3-6 months. Prescribed diet (gram protein/kilogram/bodyweight) was recorded on every study visit; measured protein intake was available in three countries. Time to death and decline in nutritional status (SGA decrease by ≥2 points) were analysed using marginal structural models with dynamic inverse probability of treatment and censoring weights. RESULTS: Out of 1738 adults (631 prescribed LPD at any point during follow-up) there were 1319 with repeated SGA measurements of which 267 (20%) declined in SGA ≥ 2 points and 565 (32.5%) died. There was no difference in survival or decline in nutritional status for patients prescribed LPD ≤0.8 g/kg ideal bodyweight (Odds Ratio (OR) for mortality 1.15 (95% Confidence interval (CI) 0.86-1.55) and OR for decline in SGA 1.11 (95% CI 0.74-1.66) in the adjusted models. In patients prescribed LPD <0.6 g/kg ideal bodyweight, the results were similar. There was a significant interaction with LPD and higher age >75 years, lower SGA, and higher comorbidity burden for both mortality and nutritional status decline. CONCLUSIONS: In older adults with CKD approaching end-stage kidney disease, a traditional LPD prescribed and monitored according to routine clinical practice in Europe appears to be safe.

Global variability of vascular and peritoneal access for chronic dialysis.

AIM: Vascular and peritoneal access are essential elements for sustainability of chronic dialysis programs. Data on availability, patterns of use, funding models, and workforce for vascular and peritoneal accesses for dialysis at a global scale is limited. METHODS: An electronic survey of national leaders of nephrology societies, consumer representative organizations, and policymakers was conducted from July to September 2018. Questions focused on types of accesses used to initiate dialysis, funding for services, and availability of providers for access creation. RESULTS: Data from 167 countries were available. In 31 countries (25% of surveyed countries), >75% of patients initiated haemodialysis (HD) with a temporary catheter. Seven countries (5% of surveyed countries) had >75% of patients initiating HD with arteriovenous fistulas or grafts. Seven countries (5% of surveyed countries) had >75% of their patients starting HD with tunnelled dialysis catheters. 57% of low-income countries (LICs) had >75% of their patients initiating HD with a temporary catheter compared to 5% of high-income countries (HICs). Shortages of surgeons to create vascular access were reported in 91% of LIC compared to 46% in HIC. Approximately 95% of participating countries in the LIC category reported shortages of surgeons for peritoneal dialysis (PD) access compared to 26% in HIC. Public funding was available for central venous catheters, fistula/graft creation, and PD catheter surgery in 57%, 54% and 54% of countries, respectively. CONCLUSION: There is a substantial variation in the availability, funding, workforce, and utilization of vascular and peritoneal access for dialysis across countries regions, with major gaps in low-income countries.

Global variations in funding and use of hemodialysis accesses: an international report using the ISN Global Kidney Health Atlas.

BACKGROUND: There is a lack of contemporary data describing global variations in vascular access for hemodialysis (HD). We used the third iteration of the International Society of Nephrology Global Kidney Health Atlas (ISN-GKHA) to highlight differences in funding and availability of hemodialysis accesses used for initiating HD across world regions. METHODS: Survey questions were directed at understanding the funding modules for obtaining vascular access and types of accesses used to initiate dialysis. An electronic survey was sent to national and regional key stakeholders affiliated with the ISN between June and September 2022. Countries that participated in the survey were categorized based on World Bank Income Classification (low-, lower-middle, upper-middle, and high-income) and by their regional affiliation with the ISN. RESULTS: Data on types of vascular access were available from 160 countries. Respondents from 35 countries (22% of surveyed countries) reported that > 50% of patients started HD with an arteriovenous fistula or graft (AVF or AVG). These rates were higher in Western Europe (n = 14; 64%), North & East Asia (n = 4; 67%), and among high-income countries (n = 24; 38%). The rates of > 50% of patients starting HD with a tunneled dialysis catheter were highest in North America & Caribbean region (n = 7; 58%) and lowest in South Asia and Newly Independent States and Russia (n = 0 in both regions). Respondents from 50% (n = 9) of low-income countries reported that > 75% of patients started HD using a temporary catheter, with the highest rates in Africa (n = 30; 75%) and Latin America (n = 14; 67%). Funding for the creation of vascular access was often through public funding and free at the point of delivery in high-income countries (n = 42; 67% for AVF/AVG, n = 44; 70% for central venous catheters). In low-income countries, private and out of pocket funding was reported as being more common (n = 8; 40% for AVF/AVG, n = 5; 25% for central venous catheters). CONCLUSIONS: High income countries exhibit variation in the use of AVF/AVG and tunneled catheters. In low-income countries, there is a higher use of temporary dialysis catheters and private funding models for access creation.

Exploring Patients' Perceptions About Chronic Kidney Disease and Their Treatment: A Qualitative Study.

BACKGROUND: Unhelpful illness perceptions can be changed by means of interventions and can lead to improved outcomes. However, little is known about illness perceptions in patients with chronic kidney disease (CKD) prior to kidney failure, and no tools exist in nephrology care to identify and support patients with unhelpful illness perceptions. Therefore, this study aims to: (1) identify meaningful and modifiable illness perceptions in patients with CKD prior to kidney failure; and (2) explore needs and requirements for identifying and supporting patients with unhelpful illness perceptions in nephrology care from patients' and healthcare professionals' perspectives. METHODS: Individual semi-structured interviews were conducted with purposive heterogeneous samples of Dutch patients with CKD (n = 17) and professionals (n = 10). Transcripts were analysed using a hybrid inductive and deductive approach: identified themes from the thematic analysis were hereafter organized according to Common-Sense Model of Self-Regulation principles. RESULTS: Illness perceptions considered most meaningful are related to the seriousness (illness identity, consequences, emotional response and illness concern) and manageability (illness coherence, personal control and treatment control) of CKD. Over time, patients developed more unhelpful seriousness-related illness perceptions and more helpful manageability-related illness perceptions, caused by: CKD diagnosis, disease progression, healthcare support and approaching kidney replacement therapy. Implementing tools to identify and discuss patients' illness perceptions was considered important, after which support for patients with unhelpful illness perceptions should be offered. Special attention should be paid towards structurally embedding psychosocial educational support for patients and caregivers to deal with CKD-related symptoms, consequences, emotions and concerns about the future. CONCLUSIONS: Several meaningful and modifiable illness perceptions do not change for the better by means of nephrology care. This underlines the need to identify and openly discuss illness perceptions and to support patients with unhelpful illness perceptions. Future studies should investigate whether implementing illness perception-based tools will indeed improve outcomes in CKD.

International Society of Nephrology first consensus guidance for preclinical animal studies in translational nephrology.

Preclinical tests in animal models are key steps in early drug development. Consequently, the International Society of Nephrology held a consensus meeting that connected experts in the global kidney community in order to provide guidance on optimal management of translational animal studies for the development of new drugs to treat kidney disease, entitled "TRANSFORM; TRAnslational Nephrology Science FOR new Medications." The meeting covered various themes, including the following: (i) selection of disease model; (ii) pharmacokinetics; (iii) interventions in late preclinical models; (iv) choice of animal; (v) statistical power; (vi) organoids and organ-on-a-chip models; and (vii) reporting of results. This guidance is the first to be provided on the optimal conduct of translational animal studies for the development of new drugs to treat kidney disease. These recommendations are designed to accelerate development of new drugs for efficacious treatment of kidney diseases, and to improve the prognosis and quality of life of patients with a variety of kidney diseases.

Defining myocardial infarction in trials of people receiving hemodialysis: consensus report from the SONG-HD MI Expert Working group.

Cardiovascular disease is the leading cause of death in patients receiving hemodialysis. Currently, there is no standardized definition of myocardial infarction (MI) for patients receiving hemodialysis. Through an international consensus process MI was established as the core CVD measure for this population in clinical trials. The Standardised Outcomes in Nephrology Group-Hemodialysis (SONG-HD) initiative convened a multidisciplinary, international working group to address the definition of MI in this population. On the basis of current evidence, the working group recommends using the Fourth Universal Definition of Myocardial Infarction with specific caveats with regard to the interpretation of "ischemic symptoms" and performing a baseline 12-lead electrocardiogram to facilitate interpretation of acute changes on subsequent tracings. The working group does not recommend obtaining baseline cardiac troponin values, though does recommend obtaining serial cardiac biomarkers in settings where ischemia is suspected. The application of an evidence-based uniform definition should increase the reliability and accuracy of trial results.

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.

Serum Potassium and Risk of Death or Kidney Replacement Therapy in Older People With CKD Stages 4-5: Eight-Year Follow-up.

RATIONALE & OBJECTIVE: Hypokalemia may accelerate kidney function decline. Both hypo- and hyperkalemia can cause sudden cardiac death. However, little is known about the relationship between serum potassium and death or the occurrence of kidney failure requiring replacement therapy (KRT). We investigated this relationship in older people with chronic kidney disease (CKD) stage 4-5. STUDY DESIGN: Prospective observational cohort study. SETTING & PARTICIPANTS: We followed 1,714 patients (≥65 years old) from the European Quality (EQUAL) study for 8 years from their first estimated glomerular filtration rate (eGFR)<20mL/min/1.73m2 measurement. EXPOSURE: Serum potassium was measured every 3 to 6 months and categorized as≤3.5,>3.5-≤4.0,>4.0-≤4.5,>4.5-≤5.0 (reference),>5.0-≤5.5, >5.5-≤6.0, and>6.0mmol/L. OUTCOME: The combined outcome death before KRT or start of KRT. ANALYTICAL APPROACH: The association between categorical and continuous time-varying potassium and death or KRT start was examined using Cox proportional hazards and restricted cubic spline analyses, adjusted for age, sex, diabetes, cardiovascular disease, renin-angiotensin-aldosterone system (RAAS) inhibition, eGFR, and subjective global assessment (SGA). RESULTS: At baseline, 66% of participants were men, 42% had diabetes, 47% cardiovascular disease, and 54% used RAAS inhibitors. Their mean age was 76±7 (SD) years, mean eGFR was 17±5 (SD) mL/min/1.73m2, and mean SGA was 6.0±1.0 (SD). Over 8 years, 414 (24%) died before starting KRT, and 595 (35%) started KRT. Adjusted hazard ratios for death or KRT according to the potassium categories were 1.6 (95% CI, 1.1-2.3), 1.4 (95% CI, 1.1-1.7), 1.1 (95% CI, 1.0-1.4), 1 (reference), 1.1 (95% CI, 0.9-1.4), 1.8 (95% CI, 1.4-2.3), and 2.2 (95% CI, 1.5-3.3). Hazard ratios were lowest at a potassium of about 4.9mmol/L. LIMITATIONS: Shorter intervals between potassium measurements would have allowed for more precise estimations. CONCLUSIONS: We observed a U-shaped relationship between serum potassium and death or KRT start among patients with incident CKD 4-5, with a nadir risk at a potassium level of 4.9mmol/L. These findings underscore the potential importance of preventing both high and low potassium in patients with CKD 4-5. PLAIN-LANGUAGE SUMMARY: Abnormal potassium blood levels may increase the risk of death or kidney function decline, especially in older people with chronic kidney disease (CKD). We studied 1,714 patients aged≥65 years with advanced CKD from the European Quality (EQUAL) study and followed them for 8 years. We found that both low and high levels of potassium were associated with an increased risk of death or start of kidney replacement therapy, with the lowest risk observed at a potassium level of 4.9 mmol/L. In patients with CKD, the focus is often on preventing high blood potassium. However, this relatively high optimum potassium level stresses the potential importance of also preventing low potassium levels in older patients with advanced CKD.

Comparative Effectiveness of Dynamic Treatment Strategies for Medication Use and Dosage: Emulating a Target Trial Using Observational Data.

BACKGROUND: Availability of detailed data from electronic health records (EHRs) has increased the potential to examine the comparative effectiveness of dynamic treatment strategies using observational data. Inverse probability (IP) weighting of dynamic marginal structural models can control for time-varying confounders. However, IP weights for continuous treatments may be sensitive to model choice. METHODS: We describe a target trial comparing strategies for treating anemia with darbepoetin in hemodialysis patients using EHR data from the UK Renal Registry 2004 to 2016. Patients received a specified dose (microgram/week) or did not receive darbepoetin. We compared 4 methods for modeling time-varying treatment: (A) logistic regression for zero dose, standard linear regression for log dose; (B) logistic regression for zero dose, heteroscedastic linear regression for log dose; (C) logistic regression for zero dose, heteroscedastic linear regression for log dose, multinomial regression for patients who recently received very low or high doses; and (D) ordinal logistic regression. RESULTS: For this dataset, method (C) was the only approach that provided a robust estimate of the mortality hazard ratio (HR), with less-extreme weights in a fully weighted analysis and no substantial change of the HR point estimate after weight truncation. After truncating IP weights at the 95th percentile, estimates were similar across the methods. CONCLUSIONS: EHR data can be used to emulate target trials estimating the comparative effectiveness of dynamic strategies adjusting treatment to evolving patient characteristics. However, model checking, monitoring of large weights, and adaptation of model strategies to account for these is essential if an aspect of treatment is continuous.

Clinical and patient-reported trajectories at end-of-life in older patients with advanced CKD.

BACKGROUND: We explore longitudinal trajectories of clinical indicators, patient-reported outcomes, and hospitalizations, in the years preceding death in a population of older patients with advanced chronic kidney disease (CKD). METHODS: The EQUAL study is a European observational prospective cohort study with an incident eGFR <20 ml/min per 1.73 m2 and ≥65 years of age. The evolution of each clinical indicator was explored using generalized additive models during the 4 years preceding death. RESULTS: We included 661 decedents with a median time to death of 2.0 years (IQR 0.9-3.2). During the years preceding death, eGFR, Subjective Global Assessment score, and blood pressure declined, with accelerations seen at 6 months preceding death. Serum hemoglobin, hematocrit, cholesterol, calcium, albumin, and sodium values declined slowly during follow-up, with accelerations observed between 6 and 12 months preceding death. Physical and mental quality of life declined linearly throughout follow-up. The number of reported symptoms was stable up to 2 years prior to death, with an acceleration observed at 1 year prior to death. The rate of hospitalization was stable at around one hospitalization per person year, increasing exponentially at 6 months preceding death. CONCLUSIONS: We identified clinically relevant physiological accelerations in patient trajectories that began ∼6 to 12 months prior to death, which are likely multifactorial in nature, but correlate with a surge in hospitalizations. Further research should focus on how to effectively use this knowledge to inform patient and family expectations, to benefit the planning of (end-of-life) care, and to establish clinical alert systems.

Association between CKD-MBD and mortality in older patients with advanced CKD-results from the EQUAL study.

BACKGROUND: Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a common complication of CKD; it is associated with higher mortality in dialysis patients, while its impact in non-dialysis patients remains mostly unknown. We investigated the associations between parathyroid hormone (PTH), phosphate and calcium (and their interactions), and all-cause, cardiovascular (CV) and non-CV mortality in older non-dialysis patients with advanced CKD. METHODS: We used data from the European Quality study, which includes patients aged ≥65 years with estimated glomerular filtration rate ≤20 mL/min/1.73 m2 from six European countries. Sequentially adjusted Cox models were used to assess the association between baseline and time-dependent CKD-MBD biomarkers and all-cause, CV and non-CV mortality. Effect modification between biomarkers was also assessed. RESULTS: In 1294 patients, the prevalence of CKD-MBD at baseline was 94%. Both PTH [adjusted hazard ratio (aHR) 1.12, 95% confidence interval (CI) 1.03-1.23, P = .01] and phosphate (aHR 1.35, 95% CI 1.00-1.84, P = .05), but not calcium (aHR 1.11, 95% CI 0.57-2.17, P = .76), were associated with all-cause mortality. Calcium was not independently associated with mortality, but modified the effect of phosphate, with the highest mortality risk found in patients with both hypercalcemia and hyperphosphatemia. PTH level was associated with CV mortality, but not with non-CV mortality, whereas phosphate was associated with both CV and non-CV mortality in most models. CONCLUSIONS: CKD-MBD is very common in older non-dialysis patients with advanced CKD. PTH and phosphate are independently associated with all-cause mortality in this population. While PTH level is only associated with CV mortality, phosphate seems to be associated with both CV and non-CV mortality.