International differences in chronic kidney disease prevalence: a key public health and epidemiologic research issue

Interactive exploration of adverse events and multimorbidity in CKD

BACKGROUND

Persons with chronic kidney disease (CKD) are at increased risk of adverse events, early mortality and multimorbidity. A detailed overview of adverse event types and rates from a large CKD cohort under regular nephrological care is missing. We generated an interactive tool to enable exploration of adverse events and their combinations in the prospective, observational German CKD (GCKD) study.

METHODS

The GCKD study enrolled 5217 participants under regular nephrological care with an estimated glomerular filtration rate of 30-60 or >60 mL/min/1.73 m2 and an overt proteinuria. Cardiovascular, cerebrovascular and peripheral vascular, kidney, infection, and cancer events, as well as deaths were adjudicated following a standard operation procedure. We summarized these time-to-event data points for exploration in interactive graphs within an R shiny app. Multivariable adjusted Cox models for time to first event were fitted. Cumulative incidence functions, Kaplan-Meier curves and intersection plots were used to display main adverse events and their combinations by sex and CKD etiology.

RESULTS

Over a median of 6.5 years, 10 271 events occurred in 2947 participants (56.5%), of which 680 participants (13.0%) died. The new publicly available interactive platform enables readers to scrutinize adverse events and their combinations as well as mortality trends as a gateway to better understand multimorbidity in CKD: incident rates per 1000 patient-years varied by event type, CKD etiology and baseline characteristics. Incidence rates for the most frequent events and their recurrence were 113.6 (cardiovascular), 75.0 (kidney) and 66.0 (infection). Participants with presumed diabetic kidney disease and men were more prone to experiencing events.

CONCLUSION

This comprehensive explorative tool to visualize adverse events (https://www.gckd.org/studienhintergrund/previous-study-results/event-analysis/), their combination, mortality and multimorbidity among persons with CKD may serve as a valuable resourec for patient care, identification of high-risk groups, health services and public health policy planning.

Association Between Magnesium Intake and Chronic Kidney Diseases and Kidney Stones in Adults Aged 50 years and Older: Dose-Response Analysis of a Nationally Representative Population-Based Study

OBJECTIVES

Higher serum magnesium concentrations have been linked to reduced risk of chronic kidney diseases (CKDs). However, the dose-response relationships between magnesium intake and CKD and kidney stones in the general population remain unknown. This study aimed to quantitatively assess the dose-response relationships between magnesium intake and CKD and kidney stones.

METHODS

Adult participants (≥50 years) from the 2007-2018 National Health and Nutrition Examination Survey were included. Magnesium intake from diet and supplements were determined with structured dietary recalls. Patients with kidney stones were identified using a standard questionnaire. CKD was defined as estimated glomerular filtration rate <60 mL/min/1.73 m2. The nonlinear relationships were explored with restricted cubic splines. Stratified analyses by sex were conducted.

RESULTS

The weighted prevalence of CKD and kidney stones was 12.16% and 13.13%, respectively. A nonlinear relationship between magnesium intake and CKD (Pfor nonlinearity<.01) and kidney stones (Pfor nonlinearity = .02) was found. There was an initial steep decrease in odds of CKD and kidney stones with increasing intakes of magnesium, and then a platform or weaker decrease in odds of CKD and kidney stones was observed beyond 350 mg/day of magnesium intake [odds ratio (95% confidence interval) for CKD: 0.60 (0.46-0.78), 0.77 (0.61-0.98) for kidney stones]. Higher magnesium intake was inversely associated with odds of CKD in both males and females, while the inverse association between higher magnesium intake and odds of kidney stones was only statistically significant in females.

CONCLUSIONS

Higher magnesium intake was nonlinearly associated with lower odds of kidney stones and CKD, and a threshold level of 350 mg/day of magnesium intake was observed in adults aged 50 years and older. These findings deserve to be confirmed by prospective cohort studies.

Overview of global healthcare policies for patients with chronic kidney disease: an integrative literature review

INTRODUCTION

Chronic kidney disease is a progressive and irreversible loss of kidney function and considerably affects the lives of patients and their families. Its high incidence necessitates efficient public policies for prevention and treatment. However, policies for chronic kidney disease education and awareness are scarce.

OBJECTIVE

To evaluate global public policies for the prevention and treatment of chronic kidney disease adopted in various regions, aiming to comprehend the differences between various models.

METHODS

This integrative review followed PRISMA recommendations and included papers published between 2016 and 2021 across several databases.

RESULTS

The 44 selected articles were categorized into three themes: structural and financial aspects of the organization of renal healthcare, access to renal healthcare or management of chronic kidney disease, and coping strategies for chronic kidney disease or kidney health. Critical analysis of the papers revealed global neglect of kidney disease in political agendas. Considerable policy variations exist between different countries and regions of the same country. Our research highlighted that free and universal health coverage, especially for the most vulnerable patients, is crucial for accessing treatment owing to the prohibitively high treatment costs.

CONCLUSION

Social, economic, and ethnic inequalities strongly correlate with disease occurrence, primarily affecting minority groups who lack health support, especially for the prevention and treatment of chronic kidney disease.

Association of Chronic Kidney Disease With Dietary Inflammatory Index in Adults Aged 50 Years and Older: Dose-Response Analysis of a Nationally Representative Population-Based Study

OBJECTIVE

Dietary inflammatory index (DII) is associated with systemic inflammatory markers, which have been linked to the development of chronic kidney disease (CKD). However, epidemiological studies on the association of DII scores with CKD are sparse. This study aimed to quantitatively assess the dose-response relationship of DII scores with the prevalence of CKD.

METHODS

Adults (≥50 years) from the 2007 to 2018 National Health and Nutrition Examination Survey (N = 12,090) were included. DII scores were calculated based on 27 nutritional parameters. The outcome of interest is the prevalence of CKD 3-5 stages, which is defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2. The nonlinear dose-response relationship of DII scores with the prevalence of CKD stages 3-5 was assessed with restricted cubic splines. Stratified analyses were conducted by age, sex, and race/ethnicity. Covariates included age, sex, body mass index, race/ethnicity, education, ratio of family income to poverty, smoking, physical activity, hypertension, diabetes, and daily intakes of total plain water, sodium, and energy.

RESULTS

The weighted prevalence of CKD stages 3-5 was 14.77%. The relationship of DII scores with CKD stages 3-5 was linear, and the odds ratios (95% confidence intervals) of CKD stages 3-5 were 0.68 (0.51-0.84) for -2 (DII score), 0.83 (0.74-0.93) for -1, 1.00 for 0 (reference value), 1.20 (1.07-1.32) for 1, 1.41 (1.16-1.66) for 2, 1.63 (1.28-1.98) for 3, 1.84 (1.34-2.34) for 4, and 2.08 (1.30-2.86) for 5. The linear relationship pattern of DII scores with CKD stages 3-5 was observed in stratified analyses by age, sex, and race/ethnicity, respectively.

CONCLUSIONS

Higher DII scores were independently and linearly associated with the odds of CKD stages 3-5, which deserves to be confirmed in further prospective cohort studies.

Prevalence of chronic kidney disease in Kazakhstan: evidence from a national cross-sectional study

To date, there have been no large-scale national studies of the prevalence of chronic kidney disease in Kazakhstan. It includes the research based on the analysis of the estimated glomerular filtration rate (eGFR). The aim of this study was to investigate the population prevalence of CKD and associated risk factors in Kazakhstan. The cross-sectional study consisted of a nationally representative sample of n = 6 720 adults aged 18 to 69 from 14 regions and 3 major cities in Kazakhstan. The study covered the period from October 2021 to May 2022. The WHO STEPS questionnaire was used for the survey. For the diagnosis of CKD, creatinine levels in collected blood samples were measured to assess eGFR. Demographic characteristics were collected and studied. The total and adjusted prevalence of factors associated with the presence of CKD were calculated and analysed using logistic regression. 73.5% (n = 4940) of participants had normal eGFR, while 25.2% (n = 1695) had mild CKD (eGFR = 60-89 mL/min/1.7 m2). The overall prevalence of CKD with eGFR < 60 ml/min/1.7 m2 was 1.3% (n = 85), of which 0.2% (n = 15) had eGFR < 45 ml/min/1.7 m2. A mild degree of CKD was most often determined in residents of the East Kazakhstan region in 10.4%, and in 7.8-8.0% of cases. The majority of CKD patients was detected in the East Kazakhstan region and Almaty city, 15.3% and 10.6% of cases respectively. In mild and CKD with GFR < 60 ml/min/1.7 m2, the age of participants was 50-69 years in 61.5% and 78.8% of cases, respectively (p < 0.001). In addition to the association with the place of residence, a statistically significant relationship was found between the risk of developing CKD and underweight (OR 1.43, 95% CI (1.09-1.88), p < 0.001), as well as the presence of obesity (OR 1.24, 95% CI (0.99-1.53), p = 0.04). We observed the prevalence of CKD with eGFR < 60 ml/min/1.7 m2 at the level of 1.3%. However, a fairly large part of study participants had a mild CKD (25.2%). The results of this study can be used for the optimization of the doctors workload and the timely provision of care to patients with CKD.

The Potential Modulatory Effects of Exercise on Skeletal Muscle Redox Status in Chronic Kidney Disease

Chronic Kidney Disease (CKD) is a global health burden with high mortality and health costs. CKD patients exhibit lower cardiorespiratory and muscular fitness, strongly associated with morbidity/mortality, which is exacerbated when they reach the need for renal replacement therapies (RRT). Muscle wasting in CKD has been associated with an inflammatory/oxidative status affecting the resident cells' microenvironment, decreasing repair capacity and leading to atrophy. Exercise may help counteracting such effects; however, the molecular mechanisms remain uncertain. Thus, trying to pinpoint and understand these mechanisms is of particular interest. This review will start with a general background about myogenesis, followed by an overview of the impact of redox imbalance as a mechanism of muscle wasting in CKD, with focus on the modulatory effect of exercise on the skeletal muscle microenvironment.

The prevalence of chronic kidney disease in South Africa - limitations of studies comparing prevalence with sub-Saharan Africa, Africa, and globally

BACKGROUND

Chronic kidney disease (CKD) is a globally significant non-communicable disorder. CKD prevalence varies between countries and within a country. We compared the prevalence rates of CKD in South Africa with sub-Saharan Africa, Africa, and globally.

METHODS

We registered a systematic review with the International Prospective Register of Systematic Reviews for prevalence studies reporting CKD stages III-V from 2013 to 2021. The analysis sought to explain any significant differences in prevalence rates. The R statistical package was used for data analysis. Comparisons included measures of effect size due to the large sample sizes analysed. We also compared sex differences in prevalence rates, common aetiologies, and type of study methodologies employed.

RESULTS

Eight studies were analysed, with two from each region. The matched prevalence rates of CKD between the various regions and South Africa showed significant differences, except for one comparison between South Africa and an African study [p = 0.09 (95% CI - 0.04-0.01)]. Both sub-Saharan African studies had a higher prevalence than South Africa. One study in Africa had a higher prevalence, while the other had a lower prevalence, whilst one Global study had a higher prevalence, and the other had a lower prevalence compared to South Africa. The statistical differences analysed using the Cramer's V test were substantially less than 0.1. Thus, differences in comparisons were largely due to differences in sample sizes rather than actual differences.

CONCLUSION

Variable prevalence rates between regions included disparities in sample size, definitions of CKD, lack of chronicity testing and heterogeneous laboratory estimations of eGFR. Improved consistency and enhanced methods for diagnosing and comparing CKD prevalence are essential.

Prediction of incident chronic kidney disease in a population with normal renal function and normo-proteinuria

Regarding the irreversible clinical course of chronic kidney disease, identifying high-risk subjects susceptible to Chronic Kidney Disease (CKD) has an important clinical implication. Previous studies have developed risk prediction models identifying high-risk individuals within a group, including those who may have experienced minor renal damage, to provide an opportunity for initiating therapies or interventions at earlier stages of CKD. To date, there were no other studies developed a prediction model with quantitative risk factors to detect the earliest stage of CKD that individuals with normal renal function in the general population may experience. We derived 11,495,668 individuals with an estimated glomerular filtration rate (eGFR) ≥90 mL/min/1.73 m2 and normo-proteinuria, who underwent health screening ≥2 times between 2009 and 2016 from the prospective nationwide registry cohort. The primary outcome was the incident CKD, defined by an eGFR <60 mL/min/1.73 m2. Sex-specific multivariate Cox regression models predicting the 8-year incident CKD risk were developed. The performance of developed models was assessed using Harrell's C and the area under the receiver operating characteristics curve (AUROC) with 10-fold cross-validation. Both men and women, who met the definition of incident CKD, were older and had more medical treatment history in hypertension and diabetes. Harrell's C and AUROC of the developed prediction models were 0.82 and 0.83 for men and 0.79 and 0.80 for women. This study developed sex-specific prediction equations with reasonable performance in a population with normal renal function.

Development of a list with renally relevant drugs as a tool to increase medicines optimisation in patients with chronic kidney disease

OBJECTIVES

Chronic kidney disease (CKD) is a common disorder all over the world. Therapeutic goals are early detection of declining renal function and implementation of adequate pharmacological treatments regarding underlying and secondary diseases. As therapy becomes more complex with increasing stages of CKD, a decision-making tool for healthcare professionals could help to ensure safe drug treatment in patients with CKD in the outpatient setting. Therefore, a list of renally relevant drugs as a decision-making tool was developed to improve medicines optimisation for CKD patients in the outpatient setting long term.

METHODS

A renally relevant drug list (RRD-list) with renally relevant drugs, based on data from a study on medicines optimisation in patients with CKD from June 2015 to March 2018, was developed at the nephrological outpatient clinic at the Klinikum Fulda, Germany. The whole study is published elsewhere. A clinical pharmacist reviewed the patients' medications, current drug-related problems and all nephrologists' recommendations, and categorised all detected drugs into renally relevant and non-renally relevant groups. The 10 most frequently detected renally relevant drug groups were summarised in the RRD-list and extended by treatment alternatives and advice.

RESULTS

The medication of 160 patients, who were receiving overall 1376 drugs, was analysed; 831 drugs were defined as renally relevant. Drug-related problems were caused by 543 renally relevant drugs. The nephrologists made 292 recommendations regarding 28 drug classes. Considering the 10 most frequent drug groups, in total 16 renally relevant drug groups with 36 drug classes were added to the RRD-list.

CONCLUSIONS

The RRD-list could be an essential tool for all healthcare professionals in their daily work, such as general practitioners and community pharmacists, for the treatment of patients with renal insufficiency.

A Resampling Method to Improve the Prognostic Model of End-Stage Kidney Disease: A Better Strategy for Imbalanced Data

Background

Prognostic models can help to identify patients at risk for end-stage kidney disease (ESKD) at an earlier stage to provide preventive medical interventions. Previous studies mostly applied the Cox proportional hazards model. The aim of this study is to present a resampling method, which can deal with imbalanced data structure for the prognostic model and help to improve predictive performance.

Methods

The electronic health records of patients with chronic kidney disease (CKD) older than 50 years during 2005–2015 collected from primary care in Belgium were used (n = 11,645). Both the Cox proportional hazards model and the logistic regression analysis were applied as reference model. Then, the resampling method, the Synthetic Minority Over-Sampling Technique-Edited Nearest Neighbor (SMOTE-ENN), was applied as a preprocessing procedure followed by the logistic regression analysis. The performance was evaluated by accuracy, the area under the curve (AUC), confusion matrix, and F₃ score.

Results

The C statistics for the Cox proportional hazards model was 0.807, while the AUC for the logistic regression analysis was 0.700, both on a comparable level to previous studies. With the model trained on the resampled set, 86.3% of patients with ESKD were correctly identified, although it was at the cost of the high misclassification rate of negative cases. The F₃ score was 0.245, much higher than 0.043 for the logistic regression analysis and 0.022 for the Cox proportional hazards model.

Conclusion

This study pointed out the imbalanced data structure and its effects on prediction accuracy, which were not thoroughly discussed in previous studies. We were able to identify patients with high risk for ESKD better from a clinical perspective by using the resampling method. But, it has the limitation of the high misclassification of negative cases. The technique can be widely used in other clinical topics when imbalanced data structure should be considered.

Epidemiology, clinical profile, management, and two-year risk complications among patients with chronic kidney disease in Spain

OBJECTIVES

To describe the epidemiology, clinical profile, treatments, and to determine cardiovascular and renal outcomes after two years of follow-up in a contemporary chronic kidneay disease (CKD) population in Spain. This was also analyzed among the DAPA-CKD-like population (patients who met most inclusion criteria of DAPA-CKD trial).

METHODS

Observational, retrospective, population-based study using BIG-PAC database. The CKD population was defined as patients ≥18 years, with at least one diagnostic code of CKD prior to the index date (January 1st, 2018). CKD was defined as estimated glomerular filtration rate (eGFR) <60mL/min/1.73m² (CKD-EPI), or albuminuria >30mg/g.

RESULTS

We identified 56,435 CKD patients after exclusions (76.4 years, 52.2% men, urine albumin-to-creatinine ratio 390.8mg/g, eGFR 49.7mL/min/1.73m²). CKD prevalence was 4.91% and incidence 2.10 per 1000 patient-years. Regarding treatments, 69.2% were taking renin-angiotensin system inhibitors (only 4.2% at maximal doses) and 3.5% of diabetic patients SGLT-2 inhibitors. During the two years of follow-up, rates of heart failure, all-cause death, myocardial infarction, stroke, and CKD were 17.9, 12.1, 7.2, 6.3, and 5.9 events per 100 patient-years, respectively. During this period, 44% of patients were hospitalized, and 6.8% died during hospitalization. Cardiovascular outcomes were more common in the DAPA-CKD-like population.

CONCLUSIONS

In Spain, CKD population is older and comorbidities, including diabetes and heart failure, are common. Cardiovascular and renal outcomes are frequent. There is room for improvement in CKD management, particularly through the use of drugs with proven cardiovascular and renal benefit.

Epidemiology, clinical profile, management, and two-year risk complications among patients with chronic kidney disease in Spain

OBJECTIVES

To describe the epidemiology, clinical profile, treatments, and to determine cardiovascular and renal outcomes after two years of follow-up in a contemporary chronic kidneay disease (CKD) population in Spain. This was also analyzed among the DAPA-CKD-like population (patients who met most inclusion criteria of DAPA-CKD trial).

METHODS

Observational, retrospective, population-based study using BIG-PAC database. The CKD population was defined as patients ≥18 years, with at least one diagnostic code of CKD prior to the index date (January 1st, 2018). CKD was defined as estimated glomerular filtration rate (eGFR) <60mL/min/1.73m2 (CKD-EPI), or albuminuria >30mg/g.

RESULTS

We identified 56,435 CKD patients after exclusions (76.4 years, 52.2% men, urine albumin-to-creatinine ratio 390.8mg/g, eGFR 49.7mL/min/1.73m2). CKD prevalence was 4.91% and incidence 2.10 per 1000 patient-years. Regarding treatments, 69.2% were taking renin-angiotensin system inhibitors (only 4.2% at maximal doses) and 3.5% of diabetic patients SGLT-2 inhibitors. During the two years of follow-up, rates of heart failure, all-cause death, myocardial infarction, stroke, and CKD were 17.9, 12.1, 7.2, 6.3, and 5.9 events per 100 patient-years, respectively. During this period, 44% of patients were hospitalized, and 6.8% died during hospitalization. Cardiovascular outcomes were more common in the DAPA-CKD-like population.

CONCLUSIONS

In Spain, CKD population is older and comorbidities, including diabetes and heart failure, are common. Cardiovascular and renal outcomes are frequent. There is room for improvement in CKD management, particularly through the use of drugs with proven cardiovascular and renal benefit.

Polymorphism in the GATM Locus Associated with Dialysis-Independent Chronic Kidney Disease but Not Dialysis-Dependent Kidney Failure

The ten most statistically significant estimated glomerular filtration rate (eGFRcrea)-associated loci from genome-wide association studies (GWAs) are tested for associations with chronic kidney disease (CKD) in 208 patients, including dialysis-independent CKD and dialysis-dependent end-stage renal disease (kidney failure). The allele A of intergenic SNP rs2453533 (near GATM) is more frequent in dialysis-independent CKD patients (n = 135, adjusted p = 0.020) but not dialysis-dependent kidney failure patients (n = 73) compared to healthy controls (n = 309). The allele C of intronic SNP rs4293393 (UMOD) is more frequent in healthy controls (adjusted p = 0.042) than in CKD patients. The Allele T of intronic SNP rs9895661 (BCAS3) is associated with decreased eGFRcys (adjusted p = 0.001) and eGFRcrea (adjusted p = 0.017). Our results provide further evidence of a genetic difference between dialysis-dialysis-independent CKD and dialysis-dependent kidney failure, and add the GATM gene locus to the list of loci associated only with dialysis-independent CKD. GATM risk allele carriers in the dialysis-independent group may have a genetic susceptibility to higher creatinine production rather than increased serum creatinine due to kidney malfunction, and therefore, do not progress to dialysis-dependent kidney failure. When using eGFRcrea for CKD diagnosis, physicians might benefit from information about creatinine-increasing loci.

Temporal Trends in the Quality of Deceased Donor Kidneys and Kidney Transplant Outcomes in Europe: an analysis by the ERA-EDTA Registry

Background

We investigated 10-year trends in deceased donor kidney quality expressed as the kidney donor risk index (KDRI) and subsequent effects on survival outcomes in a European transplant population.

Methods

Time trends in the crude and standardized KDRI between 2005 and 2015 by recipient age, sex, diabetic status and country were examined in 24 177 adult kidney transplant recipients in seven European countries. We determined 5-year patient and graft survival probabilities and the risk of death and graft loss by transplant cohort (Cohort 1: 2005–06, Cohort 2: 2007–08, Cohort 3: 2009–10) and KDRI quintile.

Results

The median crude KDRI increased by 1.3% annually, from 1.31 [interquartile range (IQR) 1.08–1.63] in 2005 to 1.47 (IQR 1.16–1.90) in 2015. This increase, i.e. lower kidney quality, was driven predominantly by increases in donor age, hypertension and donation after circulatory death. With time, the gap between the median standardized KDRI in the youngest (18–44 years) and oldest (>65 years) recipients widened. There was no difference in the median standardized KDRI by recipient sex. The median standardized KDRI was highest in Austria, the Netherlands and the Basque Country (Spain). Within each transplant cohort, the 5-year patient and graft survival probability were higher for the lowest KDRIs. There was no difference in the patient and graft survival outcomes across transplant cohorts, however, over time the survival probabilities for the highest KDRIs improved.

Conclusions

The overall quality of deceased donor kidneys transplanted between 2005 and 2015 has decreased and varies between age groups and countries. Overall patient and graft outcomes remain unchanged.

Supplemented ERA-EDTA Registry data evaluated the frequency of dialysis, kidney transplantation, and comprehensive conservative management for patients with kidney failure in Europe

The aims of this study were to determine the frequency of dialysis and kidney transplantation and to estimate the regularity of comprehensive conservative management (CCM) for patients with kidney failure in Europe. This study uses data from the ERA-EDTA Registry. Additionally, our study included supplemental data from Armenia, Germany, Hungary, Ireland, Kosovo, Luxembourg, Malta, Moldova, Montenegro, Slovenia and additional data from Israel, Italy, Slovakia using other information sources. Through an online survey, responding nephrologists estimated the frequency of CCM (i.e. planned holistic care instead of kidney replacement therapy) in 33 countries. In 2016, the overall incidence of replacement therapy for kidney failure was 132 per million population (pmp), varying from 29 (Ukraine) to 251 pmp (Greece). On 31 December 2016, the overall prevalence of kidney replacement therapy was 985 pmp, ranging from 188 (Ukraine) to 1906 pmp (Portugal). The prevalence of peritoneal dialysis (114 pmp) and home hemodialysis (28 pmp) was highest in Cyprus and Denmark respectively. The kidney transplantation rate was nearly zero in some countries and highest in Spain (64 pmp). In 28 countries with five or more responding nephrologists, the median percentage of candidates for kidney replacement therapy who were offered CCM in 2018 varied between none (Slovakia and Slovenia) and 20% (Finland) whereas the median prevalence of CCM varied between none (Slovenia) and 15% (Hungary). Thus, the substantial differences across Europe in the frequency of kidney replacement therapy and CCM indicate the need for improvement in access to various treatment options for patients with kidney failure.

Estimation of Missing Baseline Serum Creatinine for Acute Kidney Injury Diagnosis in Hospitalized Patients

INTRODUCTION

In hospitalized patients, information on preadmission kidney function is often missing, impeding timely and accurate acute kidney injury (AKI) detection and affecting results of AKI-related studies.

OBJECTIVE

In this study, we provided estimates of preadmission serum creatinine (SCr), based on a multivariate linear regression (Model 1) and random forest model (Model 2) built with different parametrizations. Their accuracy for AKI diagnosis was compared with the accuracy of commonly used surrogate methods: (i) SCr at hospital admission (first SCr) and (ii) SCr back-calculated from the assumed estimated glomerular filtration rate of 75 mL/min/1.73 m2 (eGFR 75).

METHODS

From 44,670 unique adult admissions to a tertiary referral centre between 2013 and 2015, we analysed 8,540 patients with preadmission SCr available. To control for differences in characteristics of patients with and without SCr, we used an inverse probability weighting technique.

RESULTS

Estimates of SCr were likely to be higher than true preadmission SCr in a low Cr concentration and undervalued in high concentrations although for Model 2 Complete-SCr these differences were smallest. The true cumulative incidence of AKI was 14.8%. Model 2 Complete-SCr had the best agreement for AKI diagnosis (kappa 0.811, 95% CI 0.787-0.835), while surrogate methods resulted in the lowest agreement: (kappa 0.553, 0.516-0.590) and (0.648, 0.620-0.676) for first SCr and eGFR 75, respectively.

CONCLUSIONS

Multivariable imputation of preadmission SCr, taking into account elementary admission data, improved accuracy in AKI diagnosis over commonly used surrogate methods. Random forest-based models can serve as an effective tool in research.

Worldwide Disparity in the Relation Between CKD Prevalence and Kidney Failure Risk

Introduction

The incidence of kidney replacement therapy (KRT) for kidney failure varies internationally much more than chronic kidney disease (CKD) prevalence. This ecologic study investigated the relation of CKD prevalence to KRT and mortality risks by world region.

Methods

We used data from Global Burden of Disease and KRT registries worldwide with linear models to estimate the percentages of variance in KRT incidence and all-cause mortality explained by age-adjusted prevalence of CKD stages 3 to 5, overall and by gender, in 61 countries classified in 3 regions: high income (n = 28), Eastern and Central Europe (n = 15), and other (n = 18).

Results

The incidence of KRT ranged from 89 to 378 per million population in high-income regions, 32 to 222 per million population in Central and Eastern Europe, and 22 to 493 per million population in the other region; age-adjusted CKD prevalence ranged from 5.5% to 10.4%, 7.6% to 13.7%, and 7.4% to 13.1%, respectively. The relation between these indicators was positive in high-income countries, negative in Central and Eastern Europe, and null in the other region. Age-adjusted CKD prevalence explained 40% of the variance in KRT incidence (P < 0.001) in high-income countries. The explained variance of age-adjusted mortality was close to 0 in high-income countries and positive at 19% (P = 0.10) in Central and Eastern Europe and at 11% (P = 0.17) in the other region. Results were consistent by gender.

Conclusion

This study raises awareness on the significant part of the gaps in KRT incidence across countries not explained by the number of individuals with CKD, even in high-income countries where access to KRT is not limited.

The Management of Non-Dialysis-Dependent Chronic Kidney Disease in Primary Care

BACKGROUND

Approximately 10% of adults in Germany have chronic kidney disease (CKD). The prevalence of CKD among patients being cared for by general practitioners is approximately 30%, and its prevalence in nursing homes is over 50%. An S3 guideline has been developed for the management of CKD in primary care.

METHODS

The guideline is based on publications retrieved by a systematic search of the literature for international guidelines published in the period 2013-2017, and additional searches on specific questions. It was created by the German College of General Practitioners and Family Physicians (Deutsche Gesellschaft für Allgemeinmedizin und Familienmedizin, DEGAM) and consented with the German Societies of Nephrology and Internal Medicine (DGfN, DGIM) and patient representation.

RESULTS

Upon the initial diagnosis of CKD (glomerular filtration rate [GFR] <60 mL/ min), the patient's blood pressure and urinary albumin-to-creatinine ratio (ACR) should be measured, and the urine should be examined for hematuria. Monitoring intervals are determined on an individual basis depending on the stage of disease and the patient's general state of health and personal preferences. Nephrological consultation should be obtained if the GFR is less than 30 mL/min, if CKD is initially diagnosed (GFR 30-59 mL/min) in the presence of persistent hematuria without any urological explanation or of albinuria in stage A2 or higher, if the patient has refractory hypertension requiring three or more antihypertensive drugs, or if the renal disease is rapidly progressive. The threshold for referring a patient should be kept low for persons under age 50; persons over age 70 should be referred only if warranted in consideration of their comorbidities and individual health goals.

CONCLUSION

The main elements of the treatment of CKD are the treatment of hypertension and diabetes and the modification of lifestyle factors. An innovation from the primary care practioner's perspective is the assessment of albuminuria with the albumin-to-creatinine ratio.

Enhanced prediction of hemoglobin concentration in a very large cohort of hemodialysis patients by means of deep recurrent neural networks

Erythropoiesis Stimulating Agents (ESAs) have become a standard anemia management tool for End Stage Renal Disease (ESRD) patients. However, dose optimization constitutes an extremely challenging task due to huge inter and intra-patient variability in the responses to ESA administration. Current data-based approaches to anemia control focus on learning accurate hemoglobin prediction models, which can be later utilized for testing competing treatment choices and choosing the optimal one. These methods, despite being proven effective in practice, present several shortcomings which this paper intends to tackle. Namely, they are limited to a small cohort of patients and, even then, they fail to provide suggestions when some strict requirements are not met (such as having a three month history prior to the prediction). Here, recurrent neural networks (RNNs) are used to model whole patient histories, providing predictions at every time step since the very first day. Furthermore, an unprecedented amount of data (∼110,000 patients from many different medical centers in twelve countries, without exclusion criteria) was used to train it, thus allowing it to generalize for every single patient. The resulting model outperforms state-of-the-art Hemoglobin prediction, providing excellent results even when tested on a prospective dataset. Simultaneously, it allows to bring the benefits of algorithmic anemia control to a very large group of patients.

Impact of physical activity and exercise on bone health in patients with chronic kidney disease: a systematic review of observational and experimental studies

Background

Chronic Kidney Disease (CKD) patients frequently develop life-impairing bone mineral disorders. Despite the reported impact of exercise on bone health, systematic reviews of the evidence are lacking. This review examines the association of both physical activity (PA) and the effects of different exercise interventions with bone outcomes in CKD.

Methods

English-language publications in EBSCO, Web of Science and Scopus were searched up to May 2019, from which observational and experimental studies examining the relation between PA and the effect of regular exercise on bone-imaging or -outcomes in CKD stage 3–5 adults were included. All data were extracted and recorded using a spreadsheet by two review authors. The evidence quality was rated using the Cochrane risk of bias tool and a modified Newcastle-Ottawa scale.

Results

Six observational (4 cross-sectional, 2 longitudinal) and seven experimental (2 aerobic-, 5 resistance-exercise trials) studies were included, with an overall sample size of 367 and 215 patients, respectively. Judged risk of bias was low and unclear in most observational and experimental studies, respectively. PA was positively associated with bone mineral density at lumbar spine, femoral neck and total body, but not with bone biomarkers. Resistance exercise seems to improve bone mass at femoral neck and proximal femur, with improved bone formation and inhibited bone resorption observed, despite the inconsistency of results amongst different studies.

Conclusions

There is partial evidence supporting (i) a positive relation of PA and bone outcomes, and (ii) positive effects of resistance exercise on bone health in CKD. Prospective population studies and long-term RCT trials exploring different exercise modalities measuring bone-related parameters as endpoint are currently lacking.

Incidence, prevalence and crude survival of patients starting dialysis in Portugal (2010-16): analysis of the National Health System individual registry

Background

The Portuguese Society of Nephrology (PSN) reported that Portugal has one of the highest incidences of dialysis in Europe. However, this claim was based on aggregated data supplied by dialysis providers, hampering comparisons between countries. In 2009, an individual registry of patients starting dialysis was set up by the Portuguese Ministry of Health. We analysed individual data of patients starting dialysis from January 2010 until December 2016.

Methods

Demography, starting treatment day, modality, regional distribution and outcomes, such as death, recovery of renal function, transfer to renal transplantation, peritoneal dialysis or conservative management, were extracted. Incidence, prevalence and survival analysis were calculated and compared with the PSN registry.

Results

Out of 19 190 registrations, 16 775 were incident patients (61.8% men). Yearly incidence of renal replacement therapy was 250, 248, 229, 239, 230, 231 and 244 per million population (p.m.p.) for 2010 to 2016, compared with 235, 224, 218, 230, 234, 225 and 239 p.m.p. reported by the PSN registry. On the other hand, prevalence increased from 998 p.m.p. in 2010 to 1286 p.m.p. in 2016, compared with 1010 p.m.p. in 2010 increasing to 1203 p.m.p. in 2016 from the PSN registry. The regions of Alentejo (122.9 p.m.p.) and the the Centre (160.8 p.m.p.) had the lowest regional incidence, while Lisbon had the highest (386 p.m.p. in 2016). Unadjusted survival analysis revealed that 93.5% of the patients were alive on the 91st day, whereas 85.2 and 78.3% were alive at 1 and 2 years, respectively. Crude survival at 7 years was 40%.

Conclusions

For the first time, an individual registry of patients starting dialysis in Portugal was subject to analysis and added new information about long-term survival and regional differences in the incidence and prevalence of renal replacement therapy. We were able to confirm that Portugal has one of the world's highest incidences and prevalences of dialysis. We also demonstrate, for the first time, a striking regional difference in the incidence of dialysis and an excellent early and long-term survival of patients on dialysis. These results compare well with other European countries in terms of the dialysis efficiency.

A call for harmonization of European kidney care: dialysis reimbursement and distribution of kidney replacement therapies

Background

We compare reimbursement for haemodialysis (HD) and peritoneal dialysis (PD) in European countries to assess the impact on government healthcare budgets. We discuss strategies to reduce costs by promoting sustainable dialysis and kidney transplantation.

Methods

This was a cross-sectional survey among nephrologists conducted online July–December 2016. European countries were categorized by tertiles of gross domestic product per capita (GDP). Reimbursement data were matched to kidney replacement therapy (KRT) data.

Results

The prevalence per million population of patients being treated with long-term dialysis was not significantly different across tertiles of GDP (P = 0.22). The percentage of PD increased with GDP across tertiles (4.9, 8.2, 13.4%; P &lt; 0.001). The HD-to-PD reimbursement ratio was higher in countries with the highest tertile of GDP (0.7, 1.0 versus 1.7; P = 0.007). Home HD was mainly reimbursed in countries with the highest tertile of GDP (15, 15 versus 69%; P = 0.005). The percentage of public health expenditure for reimbursement of dialysis decreased across tertiles of GDP (3.3, 1.5, 0.7%; P &lt; 0.001). Transplantation as a proportion of all KRT increased across tertiles of GDP (18.5, 39.5, 56.0%; P &lt; 0.001).

Conclusions

In Europe, dialysis has a disproportionately high impact on public health expenditure, especially in countries with a lower GDP. In these countries, the cost difference between PD and HD is smaller, and home dialysis and transplantation are less frequently provided than in countries with a higher GDP. In-depth evaluation and analysis of influential economic and political measures are needed to steer optimized reimbursement strategies for KRT.

Predicting 6-Month Mortality in Incident Elderly Dialysis Patients: A Simple Prognostic Score

AIM

Mortality in end-stage renal disease (ESRD) remains high, particularly among elderly, who represents the most rapidly growing segment of the ESRD population in wealthier countries. We developed and validated a risk score in elderly patients to predict 6-month mortality after dialysis initiation.

METHODS

We used data from a cohort of 421 patients, aged 65 years and over who started dialysis between 2009 and 2016, in our Nephrology department. The predictive score was developed using a multivariable logistic regression analysis. A bootstrapping technique was used for internal validation.

RESULTS

The overall mortality within 6 months was 14.0%. Five independent predictors were identified, and a points system was constructed: age 75 years or older (2 points), coronary artery disease (2), cerebrovascular disease with hemiplegia (2), time of nephrology care before dialysis (<3.0 months [2]; ≥3 to <12 months [1]), and serum albumin levels (3.0-3.49 g/dL [1]; <3.0 g/dL [2]). A score of 6 identified patients with a 70% risk of 6-month mortality. Model performance was good in both discrimination (area under the curve of 0.793; [95% CI 0.73-0.86]) and validation (concordance statistics of 0.791 [95% CI 0.73-0.85]).

CONCLUSIONS

We developed a simple prediction score based on readily available clinical and laboratory data that can be a practical and useful tool to assess short-term prognosis in elderly patients starting dialysis. It may help to inform patients and their families about ESRD treatment options and provide a more patient-centered overall approach to care.

Krüppel-like Factor 15: A Potential Therapeutic Target For Kidney Disease

Krüppel-like factor 15 (KLF15) is a zinc-finger transcription factor highly expressed in the glomeruli and interstitial cells of kidneys. An increasing number of studies have demonstrated a critical role for KLF15 in the kidney, involving tubular physiology, podocyte injury, renal fibrosis, and mesangial pathology. In this review, we discuss recent advances and update our overview of the functions of KLF15 in kidney biology, hoping to provide new perspectives on the progression and therapy of Chronic Kidney Disease (CKD). A better understanding of KLF15 with respect to its diverse roles in specific cells or diseases will be beneficial in pursuing novel therapeutic targets and moving forward to precision medicine.

Demographic, clinical characteristics and cardiovascular disease burden in a Portuguese cohort of older chronic kidney disease patients

Introduction:

Chronic kidney disease (CKD) is an independent risk factor for several unfavorable outcomes including cardiovascular disease (CVD), particularly in the elderly, who represent the most rapidly growing segment of the end-stage kidney disease (ESKD) population. Portugal has the highest European unadjusted incidence and prevalence rates of ESKD. In 2012, we started to follow a cohort of elderly CKD patients, we describe their baseline characteristics, risk profile, and cardiovascular disease burden.

Methods:

All CKD patients aged 65 years and older referred to our department during 2012 were enrolled. Baseline data included: demographic, CKD stage, medication, comorbid conditions. Estimated glomerular filtration rate (eGFR) was calculated by the CKD-EPI formula.

Results:

A total of 416 patients, 50% referred by primary care physicians, aged 77 ± 7 years, 52% male, with a median eGFR of 32 mL/min/1.73m² participated in the study. Fifty percent had diabetes (DM), 85% dyslipidemia, 96% hypertension; 26% were current/former smokers, and 24% had a body mass index > 30 kg/m². The prevalence of CVD was 62% and higher in stage 4-5 patients; in diabetics, it gradually increased with CKD progression (stage 3a < stage 3b < stage 4-5) (39, 58, 82%; p < 0.001).

Conclusions:

At baseline, our CKD elderly cohort had a higher burden of CVD. The prevalence of CVD was greater than in other European CKD cohorts. Lower level of eGFR was associated with a greater burden of CVD and was more pronounced in diabetics, highlighting the importance of strategically targeting cardiovascular risk reduction in these patients.

International comparison of trends in patients commencing renal replacement therapy by primary renal disease

AIM

To examine international time trends in the incidence of renal replacement therapy (RRT) for end-stage renal disease (ESRD) by primary renal disease (PRD).

METHODS

Renal registries reporting on patients starting RRT per million population for ESRD by PRD from 2005 to 2014, were identified by internet search and literature review. The average annual percentage change (AAPC) with a 95% confidence interval (CI) of the time trends was computed using Joinpoint regression.

RESULTS

There was a significant decrease in the incidence of RRT for ESRD due to diabetes mellitus (DM) in Europe (AAPC = -0.9; 95%CI -1.3; -0.5) and to hypertension/renal vascular disease (HT/RVD) in Australia (AAPC = -1.8; 95%CI -3.3; -0.3), Canada (AAPC = -2.9; 95%CI -4.4; -1.5) and Europe (AAPC = -1.1; 95%CI -2.1; -0.0). A decrease or stabilization was observed for glomerulonephritis in all regions and for autosomal dominant polycystic kidney disease (ADPKD) in all regions except for Malaysia and the Republic of Korea. An increase of 5.2-16.3% was observed for DM, HT/RVD and ADPKD in Malaysia and the Republic of Korea.

CONCLUSION

Large international differences exist in the trends in incidence of RRT by primary renal disease. Mapping of these international trends is the first step in defining the causes and successful preventative measures of CKD.

Epidemiology of IgA Nephropathy: A Global Perspective

IgA nephropathy (IgAN), or Berger's disease, is the most common primary glomerular disease worldwide, but varies largely in its geographic distribution. A systematic review of 1,619 publications from the five continental regions of the world was performed to assess the prevalence of IgAN in different worldwide regions and analyze factors responsible for geographic differences. All observational studies that described the prevalence and incidence data on glomerulonephritis were considered. IgAN is more frequent in Asian populations (45 cases per million population/y in Japan) than in Caucasians (31 cases per million population/y in France). These differences are owing to some relevant aspects: (1) systematic mass screening of urine in populations, as occurring in some Asian countries (Hong Kong, Japan, Korea, and Singapore), is not common in Western countries; (2) general practitioners and health care professionals in Western countries underestimate persistent microscopic hematuria and/or mild proteinuria in apparently healthy individuals causing late referral to a nephrologist; and (3) nephrologists adopt different indications for kidney biopsy in individuals with persistent urinary abnormalities. In addition, differences also are owing to the source of data, because the frequency of IgAN observed in a nephrology center with a high incidence of kidney biopsies is higher than in a regional renal biopsy registry that receives data from many centers. In conclusion, greater efforts should be made to diagnose IgAN earlier in individuals who manifest persistent microhematuria and/or mild proteinuria and to introduce less stringent indications for kidney biopsies. This preventive approach, followed by early therapy, may reduce the global burden of end-stage kidney disease caused by IgAN.