The CKD Outcomes and Practice Patterns Study (CKDopps): Rationale and Methods

CKD-Associated Pruritus and Clinical Outcomes in Nondialysis CKD

Rationale & Objective

Itching is a frequent symptom experienced by people with chronic kidney disease (CKD). We investigated the associations of CKD-associated pruritus (CKD-aP) with clinical outcomes.

Study Design

This was a longitudinal cohort study.

Setting & Participants

Patients from Brazil, France, and the United States enrolled in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) from 2013 to 2021, an international prospective cohort study of adults with nondialysis dependent CKD, and an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2 were included.

Exposure

CKD-aP was self-reported by response to the question: "During the past 4 weeks, to what extent were you bothered by itchy skin?"

Outcomes

The outcomes were as follows: CKD progression, kidney replacement therapy (KRT) initiation, mortality, hospitalization, cardiovascular events, infection events.

Analytical Approach

Associations with time-to-event outcomes were investigated using Cox proportional hazards models adjusted for potential confounders.

Results

There were 4,410 patients from 91 clinics with a median age of 69 years and a median eGFR at patient questionnaire completion of 29 (21-38) mL/min/1.73 m2. The proportion of patients not at all, somewhat, moderately, very much, and extremely bothered by itchy skin was 49%, 27%, 13%, 7%, and 3%, respectively. Patients with more advanced stages of CKD, older age, and greater comorbidities reported to be more likely bothered by itchy skin. Among patients at least moderately bothered, 23% were prescribed at least 1 pharmacotherapy (35% in the United States, 19% in France, 4% in Brazil), including antihistamine (10%), gabapentin (6%), topical corticosteroids (4%), pregabalin (3%), or sedating antihistamine (3%). The HR (95% CI) for patients extremely (vs not at all) bothered was 1.74 (1.11-2.73) for all-cause mortality, 1.56 (1.11-2.18) for all-cause hospitalization, and 1.84 (1.22-2.75) for cardiovascular events. As CKD-aP severity increased, patients also had higher rates of infection events (P = 0.04); CKD-aP severity was not associated with KRT initiation (P = 0.20) or CKD progression (P = 0.87).

Limitations

The limitations were 25% nonresponse rate, recall bias, and residual confounding factors.

Conclusions

These results demonstrate a strong association between severe itch and clinical outcomes, providing the nephrology community new insights into the possible adverse consequences of CKD-aP in individuals with nondialysis CKD, and warrant further exploration.

Plain-Language Summary

Chronic kidney disease-associated pruritus (CKD-aP) is a common disturbing symptom of chronic kidney disease (CKD). This article analyzes longitudinal data from the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) to describe prevalence of CKD-aP in 4,410 individuals with nondialysis CKD, and its association with clinical outcomes. We found that 51% of the surveyed population were bothered by pruritus. CKD-aP was more prevalent in those with more advanced stages of CKD, older age, and with more comorbid conditions. Compared to those not at all bothered by pruritus, those who were extremely bothered had a higher risk of all-cause mortality, hospitalizations, and cardiovascular events. Severity of CKD-aP was not associated with CKD progression or initiation of kidney replacement therapy.

Conservative Kidney Management Practice Patterns and Resources in the United States: A Cross-Sectional Analysis of CKDopps (Chronic Kidney Disease Outcomes and Practice Patterns Study) Data

Rationale & Objective

Conservative kidney management (CKM) is a viable treatment option for many patients with chronic kidney disease. However, CKM practices and resources in the United States are not well described. We undertook this study to gain a better understanding of factors influencing uptake of CKM by describing: (1) characteristics of patients who choose CKM, (2) provider practice patterns relevant to CKM, and (3) CKM resources available to providers.

Study Design

Cross-sectional study.

Setting & Participants

This study is a cross-sectional analysis of data from US nephrology clinics enrolled in the chronic kidney disease Outcomes and Practice Patterns Study (CKDopps) collected between 2014 and 2020. Data for this study includes chart-abstracted characteristics of patients with an estimated glomerular filtration rate ≤30mL/min/1.73m2 (n=1018) and available information on whether a decision had been made to pursue CKM at the time of kidney failure, patient (n=407) reports of discussions about forgoing dialysis, and provider (n=26) responses about CKM delivery and available resources in their health systems.

Analytical Approach

Descriptive statistics were used to report patient demographics, clinical information, provider demographics, and clinic characteristics.

Results

Among data from 1018 patients, 68 (7%) were recorded as planning for CKM. These patients were older, had more comorbidities, and were more likely to require assistance with transfers. Of the 407 patient surveys, 18% reported a conversation about forgoing dialysis with their nephrologist. A majority of providers felt comfortable discussing CKM; however, no clinics had a dedicated clinic or protocol for CKM.

Limitations

Inconsistent survey terminology and unlinked patient and provider responses.

Conclusions

Few patients reported discussion of forgoing dialysis with their providers and even fewer anticipated a choice of CKM on reaching kidney failure. Most providers were comfortable discussing CKM, but practiced in clinics that lacked dedicated resources. Further research is needed to improve the implementation of a CKM pathway.

Plain-Language Summary

For older comorbid adults with kidney failure, conservative kidney management (CKM) can be an appropriate treatment choice. CKM is a holistic approach with treatment goals of maximizing quality of life and preventing progression of chronic kidney disease (CKD) without initiation of dialysis. We investigated US CKM practices and found that among 1018 people with CKD, only 7% were planning for CKM. Of 407 surveyed patients, 18% reported a conversation with their provider about forgoing dialysis. In contrast, most providers felt comfortable discussing CKM; however, none reported working in an environment with a dedicated CKM clinic or protocol. Our data show the need for further CKM education in the United States as well as dedicated resources for its delivery.

Utility of the Kidney Failure Risk Equation and Estimated GFR for Estimating Time to Kidney Failure in Advanced CKD

RATIONALE & OBJECTIVE

The Kidney Failure Risk Equation (KFRE) predicts the 2-year risk of kidney failure for patients with chronic kidney disease (CKD). Translating KFRE-predicted risk or estimated glomerular filtration rate (eGFR) into time to kidney failure could inform decision making for patients approaching kidney failure.

STUDY DESIGN

Retrospective cohort.

SETTING & PARTICIPANTS

CKD Outcomes and Practice Patterns Study (CKDOPPS) cohort of patients with an eGFR<60mL/min/1.73m2 from 34 US nephrology practices (2013-2021).

EXPOSURE

2-year KFRE risk or eGFR.

OUTCOME

Kidney failure defined as initiation of dialysis or kidney transplantation.

ANALYTICAL APPROACH

Accelerated failure time (Weibull) models used to estimate the median, 25th, and 75th percentile times to kidney failure starting from KFRE values of 20%, 40%, and 50%, and from eGFR values of 20, 15, and 10mL/min/1.73m2. We examined variability in time to kidney failure by age, sex, race, diabetes status, albuminuria, and blood pressure.

RESULTS

Overall, 1,641 participants were included (mean age 69±13 years; median eGFR of 28mL/min/1.73m2 [IQR 20-37mL/min/1.73 m2]). Over a median follow-up period of 19 months (IQR, 12-30 months), 268 participants developed kidney failure, and 180 died before reaching kidney failure. The median estimated time to kidney failure was widely variable across patient characteristics from an eGFR of 20mL/min/1.73m2 and was shorter for younger age, male sex, Black (versus non-Black), diabetes (vs no diabetes), higher albuminuria, and higher blood pressure. Estimated times to kidney failure were comparably less variable across these characteristics for KFRE thresholds and eGFR of 15 or 10mL/min/1.73m2.

LIMITATIONS

Inability to account for competing risks when estimating time to kidney failure.

CONCLUSIONS

Among those with eGFR<15mL/min/1.73m2 or KFRE risk>40%), both KFRE risk and eGFR showed similar relationships with time to kidney failure. Our results demonstrate that estimating time to kidney failure in advanced CKD can inform clinical decisions and patient counseling on prognosis, regardless of whether estimates are based on eGFR or the KFRE.

PLAIN-LANGUAGE SUMMARY

Clinicians often talk to patients with advanced chronic kidney disease about the level of kidney function expressed as the estimated glomerular filtration rate (eGFR) and about the risk of developing kidney failure, which can be estimated using the Kidney Failure Risk Equation (KFRE). In a cohort of patients with advanced chronic kidney disease, we examined how eGFR and KFRE risk predictions corresponded to the time patients had until reaching kidney failure. Among those with eGFR<15mL/min/1.73m2 or KFRE risk > 40%), both KFRE risk and eGFR showed similar relationships with time to kidney failure. Estimating time to kidney failure in advanced CKD using either eGFR or KFRE can inform clinical decisions and patient counseling on prognosis.

Regional Variation in Hemoglobin Distribution Among Individuals With CKD: the ISN International Network of CKD Cohorts

Introduction

Despite recognized geographic and sex-based differences in hemoglobin in the general population, these factors are typically ignored in patients with chronic kidney disease (CKD) in whom a single therapeutic range for hemoglobin is recommended. We sought to compare the distribution of hemoglobin across international nondialysis CKD populations and evaluate predictors of hemoglobin.

Methods

In this cross-sectional study, hemoglobin distribution was evaluated in each cohort overall and stratified by sex and estimated glomerular filtration rate (eGFR). Relationships between candidate predictors and hemoglobin were assessed from linear regression models in each cohort. Estimates were subsequently pooled in a random effects model.

Results

A total of 58,613 participants from 21 adult cohorts (median eGFR range of 17-49 ml/min) and 3 pediatric cohorts (median eGFR range of 26-45 ml/min) were included with broad geographic representation. Hemoglobin values varied substantially among the cohorts, overall and within eGFR categories, with particularly low mean hemoglobin observed in women from Asian and African cohorts. Across the eGFR range, women had a lower hemoglobin compared to men, even at an eGFR of 15 ml/min (mean difference 5.3 g/l, 95% confidence interval [CI] 3.7-6.9). Lower eGFR, female sex, older age, lower body mass index, and diabetic kidney disease were all independent predictors of a lower hemoglobin value; however, this only explained a minority of variance (R2 7%-44% across cohorts).

Conclusion

There are substantial regional differences in hemoglobin distribution among individuals with CKD, and the majority of variance is unexplained by demographics, eGFR, or comorbidities. These findings call for a renewed interest in improving our understanding of hemoglobin determinants in specific CKD populations.

Iron-Deficiency Anemia in CKD: A Narrative Review for the Kidney Care Team

Anemia is a common complication of chronic kidney disease (CKD) and is associated with increased mortality and reduced health-related quality of life. Anemia is characterized by a decrease in hemoglobin, the iron-rich protein that the body uses for oxygen transport. Iron is required to produce hemoglobin, and disruptions in the iron homeostasis can lead to iron-deficiency anemia. Management of anemia in individuals with CKD is typically performed by a team of physicians, nurse practitioners, physician assistants, or registered nurses. Throughout the care continuum, the management can be enhanced by multidisciplinary care, and individuals with CKD can benefit from the involvement of other specialties, with dietitians/nutritionists playing an important role. However, a key area of unmet clinical need is how to assess and address iron-deficiency anemia. This review aims to provide an overview of iron-deficiency anemia in CKD and how this may be diagnosed and managed by the entire kidney care team, such as describing the mechanisms underlying iron homeostasis, the complications of iron-deficiency anemia, and the current challenges associated with its diagnosis and treatment in CKD. Opportunities for each multidisciplinary team member to add value to the care of individuals with CKD and iron-deficiency anemia are also described.

International practice patterns of dyslipidemia management in patients with chronic kidney disease under nephrology care: is it time to review guideline recommendations?

BACKGROUND

In contrast to guidelines related to lipid therapy in other areas, 2012 Kidney Disease Improving Global Outcomes (KDIGO) guidelines recommend conducting a lipid profile upon diagnosis of chronic kidney disease (CKD) and treating all patients older than 50 years without defining a target for lipid levels. We evaluated multinational practice patterns for lipid management in patients with advanced CKD under nephrology care.

METHODS

We analyzed lipid-lowering therapy (LLT), LDL- cholesterol (LDL-C) levels, and nephrologist-specified LDL-C goal upper limits in adult patients with eGFR < 60 ml/min from nephrology clinics in Brazil, France, Germany, and the United States (2014-2019). Models were adjusted for CKD stage, country, cardiovascular risk indicators, sex, and age.

RESULTS

LLT treatment differed significantly by country, from 51% in Germany to 61% in the US and France (p = 0.002) for statin monotherapy. For ezetimibe with or without statins, the prevalence was 0.3% in Brazil to 9% in France (< 0.001). Compared with patients not taking lipid-lowering therapy, LDL-C was lower among treated patients (p < 0.0001) and differed significantly by country (p < 0.0001). At the patient level, the LDL-C levels and statin prescription did not vary significantly by CKD stage (p = 0.09 LDL-C and p = 0.24 statin use). Between 7-23% of untreated patients in each country had LDL-C ≥ 160 mg/dL. Only 7-17% of nephrologists believed that LDL-C should be < 70 mg/dL.

CONCLUSION

There is substantial variation in practice patterns regarding LLT across countries but not across CKD stages. Treated patients appear to benefit from LDL-C lowering, yet a significant proportion of hyperlipidemia patients under nephrologist care are not receiving treatment.

DC-COX: Data collaboration Cox proportional hazards model for privacy-preserving survival analysis on multiple parties

The demand for the privacy-preserving survival analysis of medical data integrated from multiple institutions or countries has been increased. However, sharing the original medical data is difficult because of privacy concerns, and even if it could be achieved, we have to pay huge costs for cross-institutional or cross-border communications. To tackle these difficulties of privacy-preserving survival analysis on multiple parties, this study proposes a novel data collaboration Cox proportional hazards (DC-COX) model based on a data collaboration framework for horizontally and vertically partitioned data. By integrating dimensionality-reduced intermediate representations instead of the original data, DC-COX obtains a privacy-preserving survival analysis without iterative cross-institutional communications or huge computational costs. DC-COX enables each local party to obtain an approximation of the maximum likelihood model parameter, the corresponding statistic, such as the p-value, and survival curves for subgroups. Based on a bootstrap technique, we introduce a dimensionality reduction method to improve the efficiency of DC-COX. Numerical experiments demonstrate that DC-COX can compute a model parameter and the corresponding statistics with higher performance than the local party analysis. Particularly, DC-COX demonstrates outstanding performance in essential feature selection based on the p-value compared with the existing methods including the federated learning-based method.

Patiromer utilization in patients with advanced chronic kidney disease under nephrology care in Germany

Background

Hyperkalemia (HK) is a frequent condition in patients with chronic kidney disease (CKD) that is associated with high morbidity and mortality. Patiromer has recently been introduced as a potassium binder. Data on patiromer use in patients with CKD in the real-world setting in Europe are lacking. We describe time to discontinuation and changes in serum potassium levels among German CKD stage 3-5 patients starting patiromer.

Methods

Duration of patiromer use was estimated by Kaplan-Meier curve, starting at patiromer initiation and censoring for death, dialysis, transplant or loss to follow-up. Serum potassium levels and renin-angiotensin-aldosterone system inhibitor (RAASi) use are described at baseline and during follow-up, restricted to patients remaining on patiromer.

Results

We identified 140 patiromer users within our analysis sample [81% CKD stage 4/5, 83% receiving RAASi, and median K+ 5.7 (5.4, 6.3) mmol/L]. Thirty percent of patiromer users had prior history of polystyrene sulfonate use. Overall, 95% of patiromer users stayed on treatment past 1 month, with 53% continuing for over a year. Mean serum potassium levels decreased after patiromer initiation and remained stable under treatment during follow-up (up to 180 days). Among these patients, 73%-82% used RAASis during the time periods before and after patiromer initiation, with no obvious trend indicating discontinuation.

Conclusion

Real-world evidence of patiromer use in Germany shows that, in line with what has been observed in clinical trials, patients on patiromer have a reduction in serum potassium when used long-term. Moreover, most patients on patiromer do not discontinue treatment prior to 1 year after initiation.

Potential Surrogate Outcomes for Kidney Failure in Advanced CKD: Evaluation of Power and Predictive Ability in CKDopps

Rationale & Objective

Potential surrogate end points for kidney failure have been proposed in chronic kidney disease (CKD); however, they must be evaluated to ensure accurate, powerful, and harmonized research, particularly among patients with advanced CKD. The aim of the current study was to investigate the power and predictive ability of surrogate kidney failure end points in a population with moderate-to-advanced CKD.

Study Design

Analysis of longitudinal data of a large multinational CKD observational study (Chronic Kidney Disease Outcomes and Practice Patterns Study).

Setting & Participants

CKD stage 3-5 patients from Brazil, France, Germany, and the United States.

Outcomes

Reaching an estimated glomerular filtration rate (eGFR) < 15 mL/min/1.73 m² or eGFR decline of ≥40%, and composite end points of these individual end points.

Analytical Approach

Each end point was used as a time-varying indicator in the Cox model to predict the time to kidney replacement therapy (KRT; dialysis or transplant) and was compared by the number of events and prediction accuracy.

Results

8,211 patients had a median baseline eGFR of 27 mL/min/1.73 m² (interquartile range, 21-36 mL/min/1.73 m²) and 1,448 KRT events over a median follow-up of 2.7 years (interquartile range, 1.2-3.0 years). Among CKD stage 4 patients, the eGFR < 15 mL/min/1.73 m² end point had higher prognostic ability than 40% eGFR decline, but the end points were similar for CKD stage 3 patients. The combination of eGFR < 15 mL/min/1.73 m² and 40% eGFR decline had the highest prognostic ability for predicting KRT, regardless of the CKD stage. Including KRT in the composite can increase the number of events and, therefore, the power.

Limitations

Variable visit frequency resulted in variable eGFR measurement frequency.

Conclusions

The composite end point can be useful for CKD progression studies among patients with advanced CKD. Harmonized use of this approach has the potential to accelerate the translation of new discoveries to clinical practice by identifying risk factors and treatments for kidney failure.

Sex-Specific Differences in Mortality and Incident Dialysis in the Chronic Kidney Disease Outcomes and Practice Patterns Study

Introduction

More men than women start kidney replacement therapy (KRT) although the prevalence of chronic kidney disease (CKD) is higher in women than men. We therefore aimed at analyzing sex-specific differences in clinical outcomes among 8237 individuals with CKD in stages 3 to 5 from Brazil, France, Germany, and the United States participating in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps).

Methods

Fine and Gray models, evaluating the effect of sex on time to events, were adjusted for age, Black race (model A); plus diabetes, cardiovascular disease, albuminuria (model B); plus estimated glomerular filtration rate (eGFR) slope during the first 12 months after enrollment and first eGFR after enrollment (model C).

Results

There were more men than women at baseline (58% vs. 42%), men were younger than women, and men had higher eGFR (28.9 ± 11.5 vs. 27.0 ± 10.8 ml/min per 1.73 m²). Over a median follow-up of 2.7 and 2.5 years for men and women, respectively, the crude dialysis initiation and pre-emptive transplantation rates were higher in men whereas that of pre-KRT death was more similar. The adjusted subdistribution hazard ratios (SHRs) between men versus women for dialysis were 1.51 (1.27–1.80) (model A), 1.32 (1.10–1.59) (model B), and 1.50 (1.25–1.80) (model C); for pre-KRT death, were 1.25 (1.02–1.54) (model A), 1.14 (0.92–1.40) (model B), and 1.15 (0.93–1.42) (model C); for transplantation, were 1.31 (0.73–2.36) (model A), 1.44 (0.76–2.74) (model B), and 1.53 (0.79–2.94) (model C).

Conclusion

Men had a higher probability of commencing dialysis before death, unexplained by CKD progression alone. Although the causal mechanisms are uncertain, this finding helps interpret the preponderance of men in the dialysis population.

[CKD care in French nephrology practices]

BACKGROUND

To be able to assess the impact of the bundled payment system on real-life management of patients with chronic kidney disease, an overview of patient-care management before its implementation is needed.

PATIENTS AND METHODS

We describe patterns of nephrology care over 3 years in 2835 patients with moderate to severe chronic kidney disease, who were followed-up from 2013 to 2019 in the CKD-REIN cohort study. Compliance with health authority guidelines during this period is also studied.

RESULTS

At baseline, patients' mean age was 67 years, 65% were men, and 43% had chronic kidney disease stage 4 or 5. The mean number of nephrology visits increased from 1.1 to 2.7 per year, from chronic kidney disease stage 3A to stage 5. The minimum number of nephrology visits as recommended by health authorities was achieved in 84%, 63%, and 33% of patients with chronic kidney disease stages 3B, 4, and 5, respectively. In chronic kidney disease stages 4 and 5, only 34% and 40% of patients had seen a dietitian, and 33% and 54% had received information about treatment options, respectively. The average waiting time for a first appointment with a nephrologist was longer, 60 days and its duration shorter, 30 vs 38 to 40 minutes, in university hospitals compared with non-university hospitals and private clinics.

CONCLUSION

The significant gap between received and recommended care reflects human resources and organizational limits in chronic kidney disease management in the nephrology setting. Improvements with bundled payment are expected.

Physical functioning in patients with chronic kidney disease stage G3b-5 in Japan: The reach-J CKD cohort study

AIM

Chronic kidney disease (CKD) is an important public health problem. Recently, CKD has been found to be associated with poor physical functioning in community-dwelling elderly individuals. However, the physical functioning of non-dialysis (ND) patients with advanced CKD treated by nephrologists is unknown.

METHODS

Patients with ND-CKD stage G3b-5 who participated in a nationwide Reach-J CKD cohort study were included in this study. Physical functioning and physical activity were assessed by the Katz Index, Lawton-Body instrumental activities of daily living (IADL) scale, and Rapid Assessment of Physical Activity questionnaire of the international CKD Outcomes and Practice Patterns Study (CKDopps) questionnaires. Dichotomies between good and poor physical functioning and physical activity scores were explored.

RESULTS

Among 1628 patients, 84.3% had good physical functioning. Poor physical functioning was more common with older age (p < .001), higher CKD stage (p < .05), and comorbid conditions such as diabetes (p < .001), cardiovascular disease (p < .05), cerebrovascular disease (p < .001), and cancer (non-skin) (p < .05). Forty percent of the patients were inactive. Physical inactivity was more common with older age (p < .001) and higher CKD stage (p < .001).

CONCLUSION

A minority, but sizeable proportion of patients with advanced CKD treated by nephrologists in Japan have some disability in ADLs/IADLs. Nephrologists need to routinely assess the physical functioning and physical activity of patients with advanced CKD to provide individualized guidance and comprehensive support to these patients for their daily life.

Serum Biomarkers of Iron Stores Are Associated with Increased Risk of All-Cause Mortality and Cardiovascular Events in Nondialysis CKD Patients, with or without Anemia

BACKGROUND

Approximately 30%-45% of patients with nondialysis CKD have iron deficiency. Iron therapy in CKD has focused primarily on supporting erythropoiesis. In patients with or without anemia, there has not been a comprehensive approach to estimating the association between serum biomarkers of iron stores, and mortality and cardiovascular event risks.

METHODS

The study included 5145 patients from Brazil, France, the United States, and Germany enrolled in the Chronic Kidney Disease Outcomes and Practice Patterns Study, with first available transferrin saturation (TSAT) and ferritin levels as exposure variables. We used Cox models to estimate hazard ratios (HRs) for all-cause mortality and major adverse cardiovascular events (MACE), with progressive adjustment for potentially confounding variables. We also used linear spline models to further evaluate functional forms of the exposure-outcome associations.

RESULTS

Compared with patients with a TSAT of 26%-35%, those with a TSAT ≤15% had the highest adjusted risks for all-cause mortality and MACE. Spline analysis found the lowest risk at TSAT 40% for all-cause mortality and MACE. Risk of all-cause mortality, but not MACE, was also elevated at TSAT ≥46%. Effect estimates were similar after adjustment for hemoglobin. For ferritin, no directional associations were apparent, except for elevated all-cause mortality at ferritin ≥300 ng/ml.

CONCLUSIONS

Iron deficiency, as captured by TSAT, is associated with higher risk of all-cause mortality and MACE in patients with nondialysis CKD, with or without anemia. Interventional studies evaluating the effect on clinical outcomes of iron supplementation and therapies for alternative targets are needed to better inform strategies for administering exogenous iron.

Urgent-start dialysis in patients referred early to a nephrologist-the CKD-REIN prospective cohort study

BACKGROUND

The lack of a well-designed prospective study of the determinants of urgent dialysis start led us to investigate its individual- and provider-related factors in patients seeing nephrologists.

METHODS

The Chronic Kidney Disease Renal Epidemiology and Information Network (CKD-REIN) is a prospective cohort study that included 3033 patients with CKD [mean age 67 years, 65% men, mean estimated glomerular filtration rate (eGFR) 32 mL/min/1.73 m2] from 40 nationally representative nephrology clinics from 2013 to 2016 who were followed annually through 2020. Urgent-start dialysis was defined as that 'initiated imminently or <48 hours after presentation to correct life-threatening manifestations' according to the Kidney Disease: Improving Global Outcomes 2018 definition.

RESULTS

Over a 4-year (interquartile range 3.0-4.8) median follow-up, 541 patients initiated dialysis with a known start status and 86 (16%) were identified with urgent starts. The 5-year risks for the competing events of urgent and non-urgent dialysis start, pre-emptive transplantation and death were 4, 17, 3 and 15%, respectively. Fluid overload, electrolytic disorders, acute kidney injury and post-surgery kidney function worsening were the reasons most frequently reported for urgent-start dialysis. Adjusted odds ratios for urgent start were significantly higher in patients living alone {2.14 [95% confidence interval (CI) 1.08-4.25] or with low health literacy [2.22 (95% CI 1.28-3.84)], heart failure [2.60 (95% CI 1.47-4.57)] or hyperpolypharmacy [taking >10 drugs; 2.14 (95% CI 1.17-3.90)], but not with age or lower eGFR at initiation. They were lower in patients with planned dialysis modality [0.46 (95% CI 0.19-1.10)] and more nephrologist visits in the 12 months before dialysis [0.81 (95% CI 0.70-0.94)] for each visit.

CONCLUSIONS

This study highlights several patient- and provider-level factors that are important to address to reduce the burden of urgent-start dialysis.

Comparison of annual eGFR decline among primary kidney diseases in patients with CKD G3b-5: results from a REACH-J CKD cohort study

BACKGROUND

Disease-specific trajectories of renal function in advanced chronic kidney disease (CKD) are not well defined. Here, we compared these trajectories in the estimated glomerular filtration rate (eGFR) by CKD stages.

METHODS

Patients with multiple eGFR measurements during the 5-year preregistration period of the REACH-J study were enrolled. Mean annual eGFR declines were calculated from linear mixed effect models with the adjustment variables of baseline CKD stage, age, sex and the current CKD stage and the level of proteinuria (CKDA1-3).

RESULTS

Among 1,969 eligible patients with CKDG3b-5, the adjusted eGFR decline (ml/min/1.73 m²/year) was significantly faster in diabetic kidney disease (DKD) patients and polycystic kidney disease (PKD) patients than in patients with other kidney diseases (DKD, - 2.96 ± 0.13; PKD, - 2.82 ± 0.17; and others, - 1.95 ± 0.05, p < 0.01). The declines were faster with higher CKD stages. In DKD patients, the eGFR decline was significantly faster in CKDG5 than CKDG4 (- 4.10 ± 0.18 vs - 2.76 ± 0.20, p < 0.01), while these declines in PKD patients were similar. The eGFR declines in PKD patients were significantly faster than DKD patients in CKDG4 (- 2.92 ± 0.23 vs - 2.76 ± 0.20, p < 0.01) and in CKDA2 (- 3.36 ± 0.35 vs - 1.40 ± 0.26, p < 0.01).

CONCLUSION

Our study revealed the disease-specific annual eGFR declines by CKD stages and the level of proteinuria. Comparing to the other kidney diseases, the declines in PKD patients were getting faster from early stages of CKD. These results suggest the importance of CKD managements in PKD patients from the early stages.

Methods and rationale of the DISCOVER CKD global observational study

Background

Real-world data for patients with chronic kidney disease (CKD), specifically pertaining to clinical management, metabolic control, treatment patterns, quality of life (QoL) and dietary patterns, are limited. Understanding these gaps using real-world, routine care data will improve our understanding of the challenges and consequences faced by patients with CKD, and will facilitate the long-term goal of improving their management and prognosis.

Methods

DISCOVER CKD follows an enriched hybrid study design, with both retrospective and prospective patient cohorts, integrating primary and secondary data from patients with CKD from China, Italy, Japan, Sweden, the UK and the USA. Data will be prospectively captured over a 3-year period from >1000 patients with CKD who will be followed up for at least 1 year via electronic case report form entry during routine clinical visits and also via a mobile/tablet-based application, enabling the capture of patient-reported outcomes (PROs). In-depth interviews will be conducted in a subset of ∼100 patients. Separately, secondary data will be retrospectively captured from >2 000 000 patients with CKD, extracted from existing datasets and registries.

Results

The DISCOVER CKD program captures and will report on patient demographics, biomarker and laboratory measurements, medical histories, clinical outcomes, healthcare resource utilization, medications, dietary patterns, physical activity and PROs (including QoL and qualitative interviews).

Conclusions

The DISCOVER CKD program will provide contemporary real-world insight to inform clinical practice and improve our understanding of the epidemiology and clinical and economic burden of CKD, as well as determinants of clinical outcomes and PROs from a range of geographical regions in a real-world CKD setting.

Serum biomarkers of iron stores are associated with worse physical health-related quality of life (HRQoL) in non-dialysis dependent chronic kidney disease (NDD-CKD) patients with or without anemia

Background

Iron deficiency (ID) is a common condition in nondialysis-dependent chronic kidney disease (NDD-CKD) patients that is associated with poorer clinical outcomes. However, the effect of ID on health-related quality of life (HRQoL) in this population is unknown. We analyzed data from a multinational cohort of NDD-CKD Stages 3–5 patients to test the association between transferrin saturation (TSAT) index and ferritin with HRQoL.

Methods

Patients from Brazil (n = 205), France (n = 2015) and the USA (n = 293) in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps, 2013–2019) were included. We evaluated the association of TSAT and ferritin (and functional and absolute ID, defined as TSAT ≤20% and ferritin ≥300 or <50 ng/mL) on pre-specified HRQoL measures, including the 36-item Kidney Disease Quality of Life physical component summary (PCS) and mental component summary (MCS) as the primary outcomes. Models were adjusted for confounders including hemoglobin (Hb).

Results

TSAT ≤15% and ferritin <50 ng/mL and ≥300 ng/mL were associated with worse PCS scores, but not with MCS. Patients with composite TSAT ≤20% and ferritin <50 or ≥300 ng/mL had lower functional status and worse PCS scores than those with a TSAT of 20–30% and ferritin 50–299 ng/mL. Patients with a lower TSAT were less likely to perform intense physical activity. Adjustment for Hb only slightly attenuated the observed effects.

Conclusions

Low TSAT levels, as well as both low TSAT with low ferritin and low TSAT with high ferritin, are associated with worse physical HRQoL in NDD-CKD patients, even after accounting for Hb level. Interventional studies of iron therapy on HRQoL among NDD-CKD individuals are needed to confirm these findings.

A real-world longitudinal study of anemia management in non-dialysis-dependent chronic kidney disease patients: a multinational analysis of CKDopps

Previously lacking in the literature, we describe longitudinal patterns of anemia prescriptions for non-dialysis-dependent chronic kidney disease (NDD-CKD) patients under nephrologist care. We analyzed data from 2818 Stage 3-5 NDD-CKD patients from Brazil, Germany, and the US, naïve to anemia medications (oral iron, intravenous [IV] iron, or erythropoiesis stimulating agent [ESA]) at enrollment in the CKDopps. We report the cumulative incidence function (CIF) of medication initiation stratified by baseline characteristics. Even in patients with hemoglobin (Hb) < 10 g/dL, the CIF at 12 months for any anemia medication was 40%, and 28% for ESAs. Patients with TSAT < 20% had a CIF of 26% and 6% for oral and IV iron, respectively. Heart failure was associated with earlier initiation of anemia medications. IV iron was prescribed to < 10% of patients with iron deficiency. Only 40% of patients with Hb < 10 g/dL received any anemia medication within a year. Discontinuation of anemia treatment was very common. Anemia treatment is initiated in a limited number of NDD-CKD patients, even in those with guideline-based indications to treat. Hemoglobin trajectory and a history of heart failure appear to guide treatment start. These results support the concept that anemia is sub-optimally managed among NDD-CKD patients in the real-world setting.

Adherence to the Kidney Disease: Improving Global Outcomes CKD Guideline in Nephrology Practice Across Countries

Introduction

The uptake of the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 chronic kidney disease (CKD) Guideline is not fully described in real-world nephrology practice across the world.

Methods

We used baseline data from the CKD Outcomes and Practice Patterns Study (2013-2017), a 4-country cohort of patients with estimated glomerular filtration rate <60 ml/min per 1.73 m² recruited from national samples of nephrology clinics, to describe adherence to measures for monitoring and delaying CKD progression. Data were collected as in clinical practice, except laboratory measures per protocol in France.

Results

The mean age ranged from 65 years in Brazil to 72 years in Germany. Albuminuria (mostly proteinuria) was measured routinely in 36% to 43% of patients in Brazil, Germany, and the United States. Blood pressure control (≤140/90 mm Hg) ranged from 49% in France to 76% in Brazil; <40% of patients had blood pressure ≤130/80 mm Hg everywhere but Brazil (52%). More than 40% of nephrologists in Brazil reported a systolic blood pressure target ≤130 mm Hg for nondiabetic patients without proteinuria, but only 19% to 24% elsewhere. Prescription of renin-angiotensin aldosterone system inhibitors ranged from 52% in the United States to 81% in Germany. Dietary advice was more frequent for salt than protein intake; dietitian visits were uncommon. In nondiabetic patients, achievement of all 3 targets including blood pressure ≤130/80 mm Hg, renin-angiotensin aldosterone system inhibition, and dietary advice, ranged from 10% in the United States to 32% in Brazil; in treated diabetic patients, this ranged from 6% to 11% after including hemoglobin A1c target.

Conclusion

Adherence to recommendations to slow CKD progression is low in typical practice settings, and substantial variation among countries for some indicates opportunities for improvement.

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.

Management of Anemia in Nondialysis Chronic Kidney Disease: Current Recommendations, Real-World Practice, and Patient Perspectives

In nondialysis CKD (ND-CKD), anemia is a multifactorial and complex condition in which several dysfunctions dynamically contribute to a reduction in circulating hemoglobin (Hb) levels in red blood cells. Anemia is common in CKD and represents an important and modifiable risk factor for poor clinical outcomes. Importantly, symptoms related to anemia, including reduced physical functioning and fatigue, have been identified as high priorities by patients with CKD. The current management of anemia in ND-CKD (i.e., parameters to initiate treatment, Hb and iron indexes targets, choice of therapies, and effect of treatment on clinical and patient-reported outcomes) remains controversial. In this review article, we explore the epidemiology of anemia in ND-CKD and revise current recommendations and controversies in its management. Exploring data from real-world clinical practices, particularly from the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps), we highlight the current challenges to translating current recommendations to clinical practice, providing patients' perspectives of anemia and how it affects their quality of life. Finally, we summarize recent advances in the field of anemia that may change the way this condition will be managed in the future.

Chronic kidney disease progression and mortality risk profiles in Germany: results from the Chronic Kidney Disease Outcomes and Practice Patterns Study

BACKGROUND

Chronic kidney disease (CKD) progression among German patients in a representative setting has not been described previously. The Verband Deutsche Nierenzentren and Chronic Kidney Disease Outcomes and Practice Patterns Study established a longitudinal observational cohort among German CKD patients to research variations in patient care and outcomes in real-world nephrology practices.

METHODS

A cohort of CKD Stages 3 (25%) and 4 (75%) patients was established from German nephrologist-run CKD clinics in 2013-16. Linear models were used to determine the estimated glomerular filtration rate (eGFR) slope during follow-up and Cox models were used to assess outcomes of end-stage kidney disease (ESKD) and death.

RESULTS

A total of 1834 patients (median age 75 years, 58% male, 42% diabetics, median baseline eGFR 25 mL/min/1.73 m2) were followed for a median of 29 months. More than 50% had slow or no decline and 17% declined ≥5 mL/min/1.73 m2/year. After 4.5 years, the incidence of ESKD was 8% and of deaths without ESKD 16% among patients with eGFR ≥30 mL/min/1.73 m2 and 37% and 19% for eGFR <30 mL/min/1.73 m2. Adjusted models showed higher risks of ESKD or death for patients with worse kidney function at baseline, male sex, diabetes and higher blood pressure; a higher risk of ESKD with higher albuminuria; and a higher risk of death with older age or cardiovascular comorbidity.

CONCLUSIONS

Routine nephrology care of patients in Germany comprises mostly elderly patients, many with slow CKD progression. Identification of risk factors for CKD progression and mortality may help guide resources by closer follow-up of high-risk patients.

Sex-specific analysis of haemodialysis prevalence, practices and mortality over time: the Austrian Dialysis Registry from 1965 to 2014

BACKGROUND

Despite a higher prevalence of chronic kidney disease among women, more men than women start renal replacement therapy (RRT). We hypothesized that gender differences in health care access exist and therefore aimed at determining whether characteristics and outcomes of haemodialysis patients over time differ by sex.

METHODS

We studied all 28 323 adults who began haemodialysis during 1965-2014 in the Austrian Dialysis Registry, analysing trends in patient characteristics by sex and decade with mortality (via Cox regression), which was compared with the mortality of the Austrian general population.

RESULTS

More men than women started haemodialysis (60.1% men versus 39.9% women overall), with minor differences among decades and age groups. The male:female mortality rate ratio in the general population ranged from 1.2 to 2.4 for age groups >18 years and in haemodialysis patients ranged from 0.80 to 1.3 (closer to 1 than in the general population, but consistently >1 in Decades 3-5). In recent decades, diabetes and hypertension replaced glomerulonephritis as the primary cause of end-stage renal disease in both men and women. Interaction analyses showed the mortality risk associated with haemodialysis access (only recorded in Decade 5) was significantly lower for men than for women.

CONCLUSIONS

The male:female mortality rate ratio and the proportion of women starting haemodialysis were remarkably stable, which does not support the hypothesis of gender differences in health care/haemodialysis access or could imply that such differences might have persisted over decades. Future research should expand to other countries and other forms of RRT.

Risk profile, quality of life and care of patients with moderate and advanced CKD: The French CKD-REIN Cohort Study

Background

The French Chronic Kidney Disease-Renal Epidemiology and Information Network (CKD-REIN) cohort study was designed to investigate the determinants of prognosis and care of patients referred to nephrologists with moderate and advanced chronic kidney disease (CKD). We examined their baseline risk profile and experience.

Methods

We collected bioclinical and patient-reported information from 3033 outpatients with CKD and estimated glomerular filtration rates (eGFRs) of 15-60 mL/min/1.73 m2 treated at 40 nationally representative public and private facilities.

Results

The patients' median age was 69 (60-76) years, 65% were men, their mean eGFR was 33 mL/min/1.73 m2, 43% had diabetes, 24% had a history of acute kidney injury (AKI) and 57% had uncontrolled blood pressure (BP; >140/90 mmHg). Men had worse risk profiles than women and were more likely to be past or current smokers (73% versus 34%) and have cardiovascular disease (59% versus 42%), albuminuria >30 mg/mmol (or proteinuria > 50) (40% versus 30%) (all P < 0.001) and a higher median risk of end-stage renal disease within 5 years, predicted by the kidney failure risk equation {12% [interquartile range (IQR) 3-37%] versus 9% [3-31%], P = 0.008}. During the previous year, 60% of patients reported one-to-two nephrologist visits and four or more general practitioner visits; only 25% saw a dietician and 75% were prescribed five or more medications daily. Physical and mental quality of life (QoL) were poor, with scores <50/100.

Conclusions

The CKD-REIN study highlights high-risk profiles of cohort members and identifies several priorities, including improving BP control and dietary counselling and increasing doctors' awareness of AKI, polypharmacy and QoL.

Trial registration

ClinicalTrials.gov identifier: NCT03381950.

International variation in the management of mineral bone disorder in patients with chronic kidney disease: Results from CKDopps

BACKGROUND AND OBJECTIVES

Chronic kidney disease (CKD) is commonly associated with mineral and bone metabolism disorders, but these are less frequently studied in non-dialysis CKD patients than in dialysis patients. We examined and described international variation in mineral and bone disease (MBD) markers and their treatment and target levels in Stage 3-5 CKD patients.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Prospective cohort study of 7658 adult patients with eGFR <60mL/min/1.73m², excluding dialysis or transplant patients, participating in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) in Brazil, France, Germany, and the US. CKD-MBD laboratory markers included serum levels of phosphorus (P), calcium (Ca), intact parathyroid hormone (iPTH), and 25-hydroxyvitamin D (25-D). MBD treatment data included phosphate binders and vitamin D (nutritional and active). Nephrologist survey data were collected on target MBD marker levels.

RESULTS

Over two-thirds of the patients had MBD markers measured at time intervals in line with practice guidelines. P and iPTH increased and Ca decreased gradually from eGFR 60-20mL/min/1.73m² and more sharply for eGFR<20. 25-D showed no relation to eGFR. Nephrologist survey data indicated marked variation in upper target P and iPTH levels. Among patients with P>5.5mg/dL, phosphate binder use was 14% to 43% across the four countries. Among patients with PTH >300pg/mL, use of active (calcitriol and related analogs) vitamin D was 12%-51%, and use of any (active or nutritional) vitamin D was 60%-87%.

CONCLUSIONS

Although monitoring of CKD-MBD laboratory markers by nephrologists in CKDopps countries is consistent with guidelines, target levels vary notably and prescription of medications to treat abnormalities in these laboratory markers is generally low in these cross-sectional analyses. While there are opportunities to increase treatment of hyperphosphatemia, hyperparathyroidism, and vitamin D deficiency in advanced CKD, the effect on longer-term complications of these conditions requires study.

Anemia and iron deficiency among chronic kidney disease Stages 3-5ND patients in the Chronic Kidney Disease Outcomes and Practice Patterns Study: often unmeasured, variably treated

Background

International variation in anemia assessment and management practices in chronic kidney disease (CKD) is poorly understood.

Methods

We performed a cross-sectional analysis of anemia laboratory monitoring, prevalence and management in the prospective Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps). A total of 6766 participants with CKD Stages 3a–5ND from nephrology clinics in Brazil, France, Germany and the USA were included.

Results

Among patients with anemia (hemoglobin <12 g/dL), 36–58% in Brazil, the USA and Germany had repeat hemoglobin measured and 40–61% had iron indices measured within 3 months of the index hemoglobin measurement. Anemia was more common in the USA and Brazil than in France and Germany across CKD stages. Higher ferritin and lower iron saturation (TSAT) levels were observed with lower hemoglobin levels, and higher ferritin with more advanced CKD. The proportion of anemic patients with ferritin <100 ng/mL or TSAT <20% ranged from 42% in Brazil to 53% in France and Germany, and of these patients, over 40% in Brazil, Germany and the USA, compared with 27% in France, were treated with oral or intravenous iron within 3 months after hemoglobin measurement. The proportion of patients with hemoglobin <10 g/dL treated with erythropoiesis-stimulating agents ranged from 28% in the USA to 57% in Germany.

Conclusions

Hemoglobin and iron stores are measured less frequently than per guidelines. Among all regions, there was a substantial proportion of anemic patients with iron deficiency who were not treated with iron, highlighting an area for practice improvement in CKD care.

Prescription of renin-angiotensin-aldosterone system inhibitors (RAASi) and its determinants in patients with advanced CKD under nephrologist care

Renin-angiotensin-aldosterone system inhibitors (RAASi) are recommended for chronic kidney disease (CKD) patients. In this study, we describe RAASi prescription patterns in the Chronic Kidney Disease Outcomes and Practice Patterns Study (CKDopps) in Brazil, Germany, France, and the United States (US). 5870 patients (mean age 66-72 years; congestive heart failure [CHF] in 11%-19%; diabetes in 43%-54%; serum potassium ≥5 in 20%-35%) were included. RAASi prescription was more common in Germany (80%) and France (77%) than Brazil (66%) and the United States (52%), where the prevalence of prescription decreases particularly in patients with CKD stage 5. In the multivariable regression model, RAASi prescription was least common in the United States and more common in patients who were younger, had diabetes, hypertension, or less advanced CKD. In conclusion, RAASi prescription patterns vary by country, and by demographic and clinical characteristics. RAASi appear to be underused, even among patients with strong class-specific recommendations. Although the reasons for this variation could not be fully identified in this cross-sectional observation, our data indicate that the risk of hyperkalemia may contribute to the underuse of this class of agents in moderate to advanced CKD.

Pruritus and Patient Reported Outcomes in Non-Dialysis CKD

BACKGROUND AND OBJECTIVES

Among patients on hemodialysis, pruritus has been associated with poorer mental and physical quality of life, sleep quality, depression, and mortality. We evaluated patients with nondialysis CKD to describe the prevalence of pruritus, identify associated factors, and investigate associations with patient-reported outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using cross-sectional data from patient questionnaires in the CKD Outcomes and Practice Patterns Study (CKDopps), we asked patients with CKD stages 3-5 (nondialysis) from the United States, Brazil, and France to identify how much they were bothered by pruritus. Response options ranged from "not at all" to "extremely." Log-Poisson regression, yielding prevalence ratios, was used to evaluate associations of moderate-to-extreme pruritus with patient characteristics, CKD stage, self-reported depression symptoms, and restless sleep. Mixed linear regression was used to examine associations between pruritus and physical and mental component summary scores, with lower scores indicating poorer quality of life.

RESULTS

Of the 5658 CKDopps patients enrolled in the United States, Brazil, and France, 3780 (67%) answered the pruritus question. The prevalence of moderate-to-extreme pruritus was 24%, and more likely in older patients, women, and those with stage 5 CKD, lung disease, diabetes, and physician-diagnosed depression. In adjusted models, patients with moderate pruritus had physical and mental component summary scores 3.5 (95% confidence interval [95% CI], -4.6 to -2.3) and 2.3 (95% CI, -3.2 to -1.5) points lower, respectively, than patients without pruritus, and they also had a higher adjusted prevalence of patient-reported depression (prevalence ratio, 1.83; 95% CI, 1.58 to 2.11) and restless sleep (prevalence ratio, 1.69; 95% CI, 1.49 to 1.91) compared with patients without pruritus. These patient-reported outcomes were progressively worse with increasing severity of pruritus.

CONCLUSIONS

Our findings demonstrate high prevalence of pruritus in nondialysis CKD, as well as strong associations of pruritus with poor health-related quality of life, self-reported depression symptoms, and self-reported poor sleep.

Facility-Level Variations in Kidney Disease Care among Veterans with Diabetes and CKD

BACKGROUND AND OBJECTIVES

Facility-level variation has been reported among veterans receiving care for various diseases. We studied the frequency and facility-level variations of guideline-recommended practices in patients with diabetes and CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with diabetes and concomitant CKD (eGFR 15-59 ml/min per 1.73 m2, measured twice, 90 days apart) receiving care in 130 facilities across the Veterans Affairs Health Care System were included (n=281,223). We studied the proportions of patients (facility-level) receiving recommended core measures and facility-level variations of these study outcomes using median rate ratios, adjusting for various patient and provider-level factors. Median rate ratio quantifies the degree to which care may vary for similar patients receiving care at two randomly chosen facilities, with <1 being no variation and >1.2 as substantial variation between the facilities. Study outcomes included measurement of urine albumin-to-creatinine ratio/urine protein-to-creatinine ratio and blood hemoglobin concentration, prescription of statins and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, BP<140/90 mm Hg, and referral to a Veterans Affairs nephrologist (only for those with eGFR<30 ml/min per 1.73 m2).

RESULTS

Among those with eGFR 30-59 ml/min per 1.73 m2, proportion of patients receiving recommended core measures (median and interquartile range across facilities) were 37% (22%-47%) for urine albumin-to-creatinine ratio/urine protein-to-creatinine ratio, 74% (72%-79%) for hemoglobin measurement, 66% (62%-69%) for angiotensin-converting enzyme inhibitor/angiotensin receptor blocker prescription, 85% (74%-87%) for statin prescription, 47% (42%-53%) for achieving BP<140/90 mm Hg, and 13% (7%-16%) for meeting all outcome measures. Adjusted median rate ratios (95% confidence intervals) were 5.2 (4.1 to 6.4), 2.4 (2.1 to 2.6), 1.3 (1.2 to 1.3), 1.2 (1.2 to 1.3), 1.4 (1.3 to 1.4), and 4.1 (3.3 to 5.0), respectively. Median rate ratios were qualitatively similar in an analysis restricted to those with eGFR 15-29 ml/min per 1.73 m2.

CONCLUSIONS

Among patients with diabetes and CKD, at facility-level, ordering of laboratory tests, and scheduling of nephrology referrals in eligible patients remains suboptimal, with substantial variations across facilities.

Impact of sex and glucose-lowering treatments on hypoglycaemic symptoms in people with type 2 diabetes and chronic kidney disease. The French Chronic Kidney Disease - Renal Epidemiology and Information Network (CKD-REIN) Study

AIM

To describe current practices of glucose-lowering treatments in people with diabetes and chronic kidney disease (CKD), the associated glucose control and hypoglycaemic symptoms, with an emphasis on sex differences.

METHODS

Among the 3033 patients with CKD stages 3-5 recruited into the French CKD-REIN study, 645 men and 288 women had type 2 diabetes and were treated by glucose-lowering drugs.

RESULTS

Overall, 31% were treated only with insulin, 28% with combinations of insulin and another drug, 42% with non-insulin glucose-lowering drugs. In CKD stage 3, 40% of patients used metformin, 12% at stages 4&5, similar for men and women; in CKD stage 3, 53% used insulin, similar for men and women, but at stages 4&5, 59% of men and 77% of women used insulin. Patients were reasonably well controlled, with a median HbA1c of 7.1% (54mmol/mol) in men, 7.4% (57mmol/mol) in women (P=0.0003). Hypoglycaemic symptoms were reported by 40% of men and 59% of women; they were not associated with the estimated glomerular filtration rate, nor with albuminuria or with HbA1c in multivariable analyses, but they were more frequent in people treated with insulin, particularly with fast-acting and pre-mixed insulins.

CONCLUSION

Glucose-lowering treatment, HbA1c and hypoglycaemic symptoms were sex dependent. Metformin use was similar in men and women, but unexpectedly low in CKD stage 3; its use could be encouraged rather than resorting to insulin. Hypoglycaemic symptoms were frequent and need to be more closely monitored, with appropriate patient-education, especially in women.

Disparities in early mortality among chronic kidney disease patients who transition to peritoneal dialysis and hemodialysis with and without catheters

PURPOSE

The early period after chronic kidney disease (CKD) patients transition to end-stage renal disease (ESRD) represents the highest mortality risk but is variable among different patient populations and clinical circumstances. We compared early mortality outcomes among a diverse CKD population that transitioned to ESRD.

METHODS

A retrospective cohort study (1/1/2002 through 12/31/2013) of CKD patients (age ≥ 18 years) who transitioned to peritoneal dialysis (PD), hemodialysis (HD) with arteriovenous fistula/grafts, and HD with catheters was performed. Multivariable Cox regression modeling was used to estimate 6-month all-cause mortality hazard ratios (HR) among the three treatment groups after adjustment for patient and clinical characteristics.

RESULTS

Among 5373 ESRD patients (62.7 years, 41.3% females, 37.5% Hispanics, 13.3% PD, 34.9% HD with fistula/graft, 51.8% HD with catheter), 551 (10.3%) died at 6 months. Mortality rates were highest immediately after transition (299 deaths per 1000 person-years in first month). Compared to PD patients, the 6-month mortality HR (95% CI) was 1.87 (1.06-3.30) in HD with fistula/graft patients and 3.77 (2.17-6.57) in HD with catheter patients. Inpatient transition (HR 1.32), acute kidney injury (HR 2.06), and an eGFR ≥ 15 vs 5-9 (HR 1.68) at transition were also associated with higher early mortality risk.

CONCLUSION

Among a diverse CKD population who transitioned to ESRD, we observed considerable differences in early mortality risk among PD, HD with fistula/graft, and HD with catheter patients. The identification of patient-specific and clinical environmental factors related to high early mortality may provide insights for managing advanced stages of CKD and shared decision making.

A Prospective Cohort Study in Patients with Type 2 Diabetes Mellitus for Validation of Biomarkers (PROVALID) - Study Design and Baseline Characteristics

BACKGROUND/AIMS

The prevalence of diabetes mellitus type 2 and kidney disease in these patients varies widely between European countries.

METHODS

In addition to store bio-samples the "Prospective cohort study in patients with type 2 diabetes mellitus for validation of biomarkers" collects information on history, physical status, laboratory measurements and medication in 4000 patients with diabetes mellitus type 2, being taken care of at the primary level of healthcare in 5 European countries (Austria, Hungary, Netherlands, Poland and Scotland). Next to comparing the rate of loss of eGFR between the countries, a further objective of the PROVALID study is to determine the 5-year cumulative incidence of renal and cardiovascular outcomes.

RESULTS

The mean age of the population recruited is 62.9±10 years, 54.6% are male and the mean BMI is 30.9±5.4 kg/m2. Metabolic control (median HBA1c 6.8 % (6.2; 7.5)) is achieved via administration of metformin in 67.4% of the patients and insulin in 30.3%. Median systolic and diastolic blood pressure at recruitment is 135 (125; 146) and 80 (72; 85) mmHg, 65.4% of subjects received RAAS blocking agents. Mean eGFR is 80.7±29.2 ml/min/1.73m2 and median baseline albumin/creatinine ratio 8.3 mg (IQR: 3.8 and 25.1).

CONCLUSION

PROVALID will provide information on incidence and progression of renal and cardiovascular disease and therapy in patients with type 2 diabetes mellitus in different European countries. Thus, in contrast to many other cohort studies we will be able to associate national clinical practise pattern with outcome in this highly vulnerable patient population.

Global coverage of health information systems for kidney disease: availability, challenges, and opportunities for development

Development and planning of health care services requires robust health information systems to define the burden of disease, inform policy development, and identify opportunities to improve service provision. The global coverage of kidney disease health information systems has not been well reported, despite their potential to enhance care. As part of the Global Kidney Health Atlas, a cross-sectional survey conducted by the International Society of Nephrology, data were collected from 117 United Nations member states on the coverage and scope of kidney disease health information systems and surveillance practices. Dialysis and transplant registries were more common in high-income countries. Few countries reported having nondialysis chronic kidney disease and acute kidney injury registries. Although 62% of countries overall could estimate their prevalence of chronic kidney disease, less than 24% of low-income countries had access to the same data. Almost all countries offered chronic kidney disease testing to patients with diabetes and hypertension, but few to high-risk ethnic groups. Two-thirds of countries were unable to determine their burden of acute kidney injury. Given the substantial heterogeneity in the availability of health information systems, especially in low-income countries and across nondialysis chronic kidney disease and acute kidney injury, a global framework for prioritizing development of these systems in areas of greatest need is warranted.

Analysis of survival for patients with chronic kidney disease primarily related to renal cancer surgery

OBJECTIVES

To evaluate predictors of long-term survival for patients with chronic kidney disease primarily due to surgery (CKD-S). Patients with CKD-S have generally good survival that approximates patients who do not have CKD even after renal cancer surgery (RCS), yet there may be heterogeneity within this cohort.

PATIENTS AND METHODS

From 1997 to 2008, 4 246 patients underwent RCS at our centre. The median (interquartile range [IQR]) follow-up was 9.4 (7.3-11.0) years. New baseline glomerular filtration rate (GFR) was defined as highest GFR between nadir and 6 weeks after RCS. We retrospectively evaluated three cohorts: no-CKD (new baseline GFR of ≥60 mL/min/1.73 m² ); CKD-S (new baseline GFR of <60 mL/min/1.73 m² but preoperative GFR of ≥60 mL/min/1.73 m² ); and CKD due to medical aetiologies who then require RCS (CKD-M/S, preoperative and new baseline GFR both <60 mL/min/1.73 m² ). Analysis focused primarily on non-renal cancer-related survival (NRCRS) for the CKD-S cohort. Kaplan-Meier analysis assessed the longitudinal impact of new baseline GFR (45-60 mL/min/1.73 m² vs <45 mL/min/1.73 m² ) and Cox regression evaluated relative impact of preoperative GFR, new baseline GFR, and relevant demographics/comorbidities.

RESULTS

Of the 4 246 patients who underwent RCS, 931 had CKD-S and 1 113 had CKD-M/S, whilst 2 202 had no-CKD even after RCS. Partial/radical nephrectomy (PN/RN) was performed in 54%/46% of the patients, respectively. For CKD-S, 641 patients had a new baseline GFR of 45-60 mL/min/1.73 m² and 290 had a new baseline GFR of <45 mL/min/1.73 m² . Kaplan-Meier analysis showed significantly reduced NRCRS for patients with CKD-S with a GFR of <45 mL/min/1.73 m² compared to those with no-CKD or CKD-S with a GFR of 45-60 mL/min/1.73 m² (both P ≤ 0.004), and competing risk analysis confirmed this (P < 0.001). Age, gender, heart disease, and new baseline GFR were all associated independently with NRCRS for patients with CKD-S (all P ≤ 0.02).

CONCLUSION

Our data suggest that CKD-S is heterogeneous, and patients with a reduced new baseline GFR have compromised survival, particularly if <45 mL/min/1.73 m² . Our findings may have implications regarding choice of PN/RN in patients at risk of developing CKD-S.

A national surveillance project on chronic kidney disease management in Canadian primary care: a study protocol

INTRODUCTION

Effective chronic disease care is dependent on well-organised quality improvement (QI) strategies that monitor processes of care and outcomes for optimal care delivery. Although healthcare is provincially/territorially structured in Canada, there are national networks such as the Canadian Primary Care Sentinel Surveillance Network (CPCSSN) as important facilitators for national QI-based studies to improve chronic disease care. The goal of our study is to improve the understanding of how patients with chronic kidney disease (CKD) are managed in primary care and the variation across practices and provinces and territories to drive improvements in care delivery.

METHODS AND ANALYSIS

The CPCSSN database contains anonymised health information from the electronic medical records for patients of participating primary care practices (PCPs) across Canada (n=1200). The dataset includes information on patient sociodemographics, medications, laboratory results and comorbidities. Leveraging validated algorithms, case definitions and guidelines will help define CKD and the related processes of care, and these enable us to: (1) determine prevalent CKD burden; (2) ascertain the current practice pattern on risk identification and management of CKD and (3) study variation in care indicators (eg, achievement of blood pressure and proteinuria targets) and referral pattern for specialist kidney care. The process of care outcomes will be stratified across patients' demographics as well as provider and regional (provincial/territorial) characteristics. The prevalence of CKD stages 3-5 will be presented as age-sex standardised prevalence estimates stratified by province and as weighted averages for population rates with 95% CIs using census data. For each PCP, age-sex standardised prevalence will be calculated and compared with expected standardised prevalence estimates. The process-based outcomes will be defined using established methods.

ETHICS AND DISSEMINATION

The CPCSSN is committed to high ethical standards when dealing with individual data collected, and this work is reviewed and approved by the Network Scientific Committee. The results will be published in peer-reviewed journals and presented at relevant national and international scientific meetings.

Low lean tissue mass is an independent risk factor for mortality in patients with stages 4 and 5 non-dialysis chronic kidney disease

Background: Mortality in patients with stages 4 and 5 chronic kidney disease (CKD) is higher than in the general population. Body composition predicts mortality. Our objective was to evaluate the effect of body composition on mortality in patients with stages 4 and 5 non-dialysis CKD. Methods: We performed a prospective study of 356 patients with stages 4 and 5 non-dialysis CKD. At baseline, we recorded general characteristics, history of cardiovascular events, body composition, serum inflammatory markers, nutrition and cardiac biomarkers. Body composition was analysed using bioimpedance spectroscopy. We recorded the lean tissue index (LTI), fat tissue index (FTI) and overhydration (OH). During a median (range) follow-up of 22 (3-49) months, we recorded mortality, cardiovascular events and progress to renal replacement therapy. Results: At baseline, mean (± standard deviation) age was 67 ± 13 years (men 64%; diabetes 36%). Mean body mass index was 28.2 ± 12.8 kg/m2, the FTI was 12.3 ± 5.6 kg/m2, the LTI was 15.7 ± 3.4 kg/m2 and median (interquartile range) OH was 0.6 (-0.4 to 1.5) L. Sixty-four (18%) patients died during follow-up. The univariate Cox analysis showed an association between mortality and age, low LTI, high Charlson comorbidity index, previous cardiovascular events, OH, low albumin and prealbumin levels, and high C-reactive protein levels. Kaplan-Meier analysis revealed higher survival in patients with a higher LTI (log-rank, 9.47; P = 0.002). The multivariate Cox analysis confirmed an association between mortality and low LTI (P = 0.031), previous cardiovascular events (P = 0.003) and high Charlson comorbidity index (P = 0.01). We did not find any association between body composition and cardiovascular events or renal replacement therapy. Conclusions: A low LTI is an independent factor for mortality in patients with stages 4 and 5 CKD.

Facility Practice Variation to Help Understand the Effects of Public Policy: Insights from the Dialysis Outcomes and Practice Patterns Study (DOPPS)

Recent Centers for Medicare & Medicaid Services policies have used dialysis facility practice variation to develop public ratings and adjust payments. In the Dialysis Facility Compare star rating system (DFC SRS), facility-relative rates of performance-based clinical measures varied nearly two-fold for mortality (standardized mortality ratio; 10th/90th percentiles: 0.71, 1.34) and hospitalization (standardized hospitalization ratio; 10th/90th percentiles: 0.64, 1.37), and nearly four-fold for transfusion (standardized transfusion ratio; 10th/90th percentiles: 0.43, 1.65). Medicare claims data (from July of 2014) demonstrate that facility variation for the proportions of patients on hemodialysis hospitalized (10th/90th percentiles: 27%, 50%) and transfused (10th/90th percentiles: 3%, 17%) within 6 months that far exceeds relatively modest recent overall longitudinal trends. DFC SRS-rated facility variation is also substantial for fistula (10th/90th percentiles: 50%, 78%) and catheter use >90 days (10th/90th percentiles: 3%, 19%). By contrast, DFC SRS-rated facility distributions for adult hemodialysis Kt/V>1.2 (10th/90th percentiles: 84%, 97%) and total serum calcium >10.2 mg/dl (median, 1%; 75th/90th percentiles: 3%, 5%) are quite narrow and may be of questionable value. Likewise, variation in the US Dialysis Outcomes and Practice Patterns Study is over two-fold for facility median serum parathyroid hormone (10th/90th percentiles: 290 pg/ml, 629 pg/ml) and ferritin (10th/90th percentiles: 469 ng/ml, 1143 ng/ml) levels, and facility mean treatment time varies by 30 minutes (10th/90th percentiles: 204 minutes, 234 minutes). Rising serum parathyroid hormone and ferritin levels, and generally short dialysis treatment time, represent areas unchecked by existing policy; both overall trends and facility variation in these values may reflect unintended consequences of policy or reimbursement pressures and therefore raise concern. Additionally, outcomes in the transition period from advanced CKD to dialysis remain poor, and policy initiatives and performance accountability in this area remain insufficient. Innovative models of comprehensive care in advanced CKD and the early dialysis period which are more amenable to policy oversight are needed. In summary, facility variation is typically larger than prevailing longitudinal trends, and should not be overlooked. The combination of nationally representative observational databases (e.g., the Dialysis Outcomes and Practice Patterns Study) and ESRD registries can provide policy makers with additional tools to evaluate facility variation, develop policies, and monitor unintended effects.