A validation study of the Canadian Organ Replacement Register

Mental health and addiction service utilization among people living with chronic kidney disease

BACKGROUND

Mental health problems, particularly anxiety and depression, are common in patients with chronic kidney disease (CKD) and negatively impact quality of life, treatment adherence and mortality. However, the degree to which mental health and addiction services are utilized by those with CKD is unknown. We examined the history of mental health and addiction service use of individuals across levels of kidney function.

METHODS

We performed a population-based cross-sectional study using linked healthcare databases from Ontario, Canada from 2009 to 2017. We abstracted the prevalence of individuals with mental health and addiction service use within the previous 3 years across levels of kidney function [estimated glomerular filtration rate (eGFR) ≥60, 45 to <60, 30 to <45, 15 to <30, <15 ml/min/1.73 m2 and maintenance dialysis]. We calculated prevalence ratios (PRs) to compare prevalence across kidney function strata, while adjusting for age, sex, year of cohort entry, urban versus rural location, area-level marginalization and Charlson comorbidity index.

RESULTS

Of 5 956 589 adults, 9% (n = 534 605) had an eGFR <60 ml/min/1.73 m2 or were receiving maintenance dialysis. Fewer individuals with an eGFR <60 ml/min/1.73 m2 had a history of any mental health and addiction service utilization (crude prevalence range 28-31%) compared with individuals with an eGFR ≥60 ml/min/1.73 m2 (35%). Compared with an eGFR ≥60 ml/min/1.73 m2, the lowest prevalence of individuals with any mental health and addiction service utilization was among those with an eGFR of 15 to <30 ml/min/1.73 m2 {adjusted PR 0.86 [95% confidence interval (CI) 0.85 to 0.88]}, an eGFR <15 ml/min/1.73 m2 [adjusted PR 0.81 (95% CI 0.76-0.86)] and those receiving maintenance dialysis [adjusted PR 0.83 (95% CI 0.81-0.84)]. Less use of outpatient services accounted for differences in service utilization.

CONCLUSIONS

Mental health and addiction service utilization is common but less so in individuals with advanced CKD in Ontario, Canada.

Association Between the Dialysate Bicarbonate and the Pre-dialysis Serum Bicarbonate Concentration in Maintenance Hemodialysis: A Retrospective Cohort Study

Background

It is unclear whether the use of higher dialysate bicarbonate concentrations is associated with clinically relevant changes in the pre-dialysis serum bicarbonate concentration.

Objective

The objective is to examine the association between the dialysate bicarbonate prescription and the pre-dialysis serum bicarbonate concentration.

Design

This is a retrospective cohort study.

Setting

The study was performed using linked administrative health care databases in Ontario, Canada.

Patients

Prevalent adults receiving maintenance in-center hemodialysis as of April 1, 2020 (n = 5414) were included.

Measurements

Patients were grouped into the following dialysate bicarbonate categories at the dialysis center-level: individualized (adjustment based on pre-dialysis serum bicarbonate concentration) or standardized (>90% of patients received the same dialysate bicarbonate concentration). The standardized category was stratified by concentration: 35, 36 to 37, and ≥38 mmol/L. The primary outcome was the mean outpatient pre-dialysis serum bicarbonate concentration at the patient level.

Methods

We examined the association between dialysate bicarbonate category and pre-dialysis serum bicarbonate using an adjusted linear mixed model.

Results

All dialysate bicarbonate categories had a mean pre-dialysis serum bicarbonate concentration within the normal range. In the individualized category, 91% achieved a pre-dialysis serum bicarbonate ≥22 mmol/L, compared to 87% in the standardized category. Patients in the standardized category tended to have a serum bicarbonate that was 0.25 (95% confidence interval [CI] = -0.93, 0.43) mmol/L lower than patients in the individualized category. Relative to patients in the 35 mmol/L category, patients in the 36 to 37 and ≥38 mmol/L categories tended to have a serum bicarbonate that was 0.70 (95% CI = -0.30, 1.70) mmol/L and 0.87 (95% CI = 0.14, 1.60) mmol/L higher, respectively. There was no effect modification by age, sex, or history of chronic lung disease.

Limitations

We could not directly confirm that all laboratory measurements were pre-dialysis. Data on prescribed dialysate bicarbonate concentrations for individual dialysis sessions were not available, which may have led to some misclassification, and adherence to a practice of individualization could not be measured. Residual confounding is possible.

Conclusions

We found no significant difference in the pre-dialysis serum bicarbonate concentration irrespective of whether an individualized or standardized dialysate bicarbonate was used. Dialysate bicarbonate concentrations ≥38 mmol/L (vs 35 mmol/L) may increase the pre-dialysis serum bicarbonate concentration by 0.9 mmol/L.

Outcomes of Integrated Home Dialysis Care: Results From the Canadian Organ Replacement Register

RATIONALE & OBJECTIVE

The integrated home dialysis model proposes the initiation of kidney replacement therapy (KRT) with peritoneal dialysis (PD) and a timely transition to home hemodialysis (HHD) after PD ends. We compared the outcomes of patients transitioning from PD to HHD with those initiating KRT with HHD.

STUDY DESIGN

Observational analysis of the Canadian Organ Replacement Register (CORR).

SETTINGS & PARTICIPANTS

All patients who initiated PD or HHD within the first 90 days of KRT between 2005 and 2018.

EXPOSURE

Patients transitioning from PD to HHD (PD+HHD group) versus patients initiating KRT with HHD (HHD group).

OUTCOME

(1) A composite of all-cause mortality and modality transfer (to in-center hemodialysis or PD for 90 days) and (2) all hospitalizations (considered as recurrent events).

ANALYTICAL APPROACH

A propensity score analysis for which PD+HHD patients were matched 1:1 to (1) incident HHD patients ("incident-match" analysis) or (2) HHD patients with a KRT vintage at least equivalent to the vintage of PD+HHD patients at the transition time ("vintage-matched" analysis). Cause-specific hazards models (composite outcome) and shared frailty models (hospitalization) were used to compare groups.

RESULTS

Among 63,327 individuals in the CORR, 163 PD+HHD patients (median of 1.9 years in PD) and 711 HHD patients were identified. In the incident-match analysis, compared to the HHD patients, the PD+HHD group had a similar risk of the composite outcome (HR, 0.88 [95% CI, 0.58-1.32]) and hospitalizations (HR, 1.04 [95% CI, 0.76-1.41]). In the vintage-match analysis, PD+HHD patients had a lower hazard for the composite outcome (HR, 0.61 [95% CI, 0.40-0.94]) but a similar hospitalization risk (HR, 0.85 [95% CI, 0.59-1.24]).

LIMITATIONS

Risk of survivor bias in the PD+HHD cohort and residual confounding.

CONCLUSIONS

Controlling for KRT vintage, the patients transitioning from PD to HHD had better clinical outcomes than the incident HHD patients. These data support the use of integrated home dialysis for patients initiating home-based KRT.

PLAIN-LANGUAGE SUMMARY

The integrated home dialysis model proposes the initiation of dialysis with peritoneal dialysis (PD) and subsequent transition to home hemodialysis (HHD) once PD is no longer feasible. It allows patients to benefit from initial lifestyle advantages of PD and to continue home-based treatments after its termination. However, some patients may prefer to initiate dialysis with HHD from the outset. In this study, we compared the long-term clinical outcomes of both approaches using a large Canadian dialysis register. We found that both options led to a similar risk of hospitalization. In contrast, the PD-to-HHD model led to improved survival when controlling for the duration of kidney failure.

Development and Validation of a Predictive Risk Algorithm for Bleeding in Individuals on Long-term Hemodialysis: An International Prospective Cohort Study (BLEED-HD)

Background

Individuals with kidney disease are at a high risk of bleeding and as such tools that identify those at highest risk may aid mitigation strategies.

Objective

We set out to develop and validate a prediction equation (BLEED-HD) to identify patients on maintenance hemodialysis at high risk of bleeding.

Design

International prospective cohort study (development); retrospective cohort study (validation).

Settings

Development: 15 countries (Dialysis Outcomes and Practice Patterns Study [DOPPS] phase 2-6 from 2002 to 2018); Validation: Ontario, Canada.

Patients

Development: 53 147 patients; Validation: 19 318 patients.

Measurements

Hospitalization for a bleeding event.

Methods

Cox proportional hazards models.

Results

Among the DOPPS cohort (mean age, 63.7 years; female, 39.7%), a bleeding event occurred in 2773 patients (5.2%, event rate 32 per 1000 person-years), with a median follow-up of 1.6 (interquartile range [IQR], 0.9-2.1) years. BLEED-HD included 6 variables: age, sex, country, previous gastrointestinal bleeding, prosthetic heart valve, and vitamin K antagonist use. The observed 3-year probability of bleeding by deciles of risk ranged from 2.2% to 10.8%. Model discrimination was low to moderate (c-statistic = 0.65) with excellent calibration (Brier score range = 0.036-0.095). Discrimination and calibration of BLEED-HD were similar in an external validation of 19 318 patients from Ontario, Canada. Compared to existing bleeding scores, BLEED-HD demonstrated better discrimination and calibration (c-statistic: HEMORRHAGE = 0.59, HAS-BLED = 0.59, and ATRIA = 0.57, c-stat difference, net reclassification index [NRI], and integrated discrimination index [IDI] all P value <.0001).

Limitations

Dialysis procedure anticoagulation was not available; validation cohort was considerably older than the development cohort.

Conclusion

In patients on maintenance hemodialysis, BLEED-HD is a simple risk equation that may be more applicable than existing risk tools in predicting the risk of bleeding in this high-risk population.

Opioid prescribing practices in chronic kidney disease: a population-based cohort study

BACKGROUND

Chronic pain is common, and its management is complex in patients with chronic kidney disease (CKD), but limited data are available on opioid prescribing. We examined opioid prescribing for non-cancer and non-end-of-life care in patients with CKD.

METHODS

This was a population-based retrospective cohort study using administrative databases in Ontario, Canada which included adults with CKD defined by an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 from 1 November 2012 to 31 December 2018 and estimated the proportion of opioid prescriptions (type, duration, dose, potentially inappropriate prescribing, etc.) within 1 year of cohort entry. Prescriptions had to precede dialysis, kidney transplant or death.

RESULTS

We included 680 445 adults with CKD, and 198 063 (29.1%) were prescribed opioids. Codeine (14.9%) and hydromorphone (7.2%) were the most common opioids. Among opioid users, 24.3% had repeated or long-term use, 26.1% were prescribed high doses and 56.8% were new users. Opioid users were more likely to be female, had cardiac disease or a mental health diagnosis, and had more healthcare visits. The proportions for potentially inappropriate prescribing indicators varied (e.g. 50.1% with eGFR <30 were prescribed codeine, and 20.6% of opioid users were concurrently prescribed benzodiazepines, while 7.2% with eGFR <30 mL/min/1.73 m2 were prescribed morphine, and 7.0% were received more than one opioid concurrently). Opioid prescriptions declined with time (2013 cohort: 31.1% versus 2018 cohort: 24.5%; p <0.0001), as did indicators of potentially inappropriate prescribing.

CONCLUSIONS

Opioid use was common in patients with CKD. While opioid prescriptions and potentially inappropriate prescribing have declined in recent years, interventions to improve pain management without the use of opioids and education on safer prescribing practices are needed.

KIdney aNd blooD prESsure ouTcomes in Childhood Cancer Survivors: Description of Clinical Research Protocol of the KINDEST-CCS Study

Background

Approximately 30% of childhood cancer survivors (CCSs) will develop chronic kidney disease (CKD) or hypertension 15 to 20 years after treatment ends. The incidence of CKD and hypertension in the 5-year window after cancer therapy is unknown. Moreover, extent of monitoring of CCS with CKD and associated complications in current practice is underexplored. To inform the development of new and existing care guidelines for CCS, the epidemiology and monitoring of CKD and hypertension in the early period following cancer therapy warrants further investigation.

Objective

To describe the design and methods of the KIdney aNd blooD prESsure ouTcomes in Childhood Cancer Survivors study, which aims to evaluate the burden of late kidney and blood pressure outcomes in the first ~10 years after cancer therapy, the extent of appropriate screening and complications monitoring for CKD and hypertension, and whether patient, disease/treatment, or system factors are associated with these outcomes.

Design

Two distinct, but related studies; a prospective cohort study and a retrospective cohort study.

Setting

Five Ontario pediatric oncology centers.

Patients

The prospective study will involve 500 CCS at high risk for these late effects due to cancer therapy, and the retrospective study involves 5,000 CCS ≤ 18 years old treated for cancer between January 2008 and December 2020.

Measurements

Chronic kidney disease is defined as Estimated glomerular filtration rate <90 mL/min/1.73 m² or albumin-to-creatinine ratio ≥ 3mg/mmol. Hypertension is defined by 2017 American Academy of Pediatrics guidelines.

Methods

Prospective study: we aim to investigate CKD and hypertension prevalence and the extent to which they persist at 3- and 5-year follow-up in CCS after cancer therapy. We will collect detailed biologic and clinical data, calculate CKD and hypertension prevalence, and progression at 3- and 5-years post-therapy. Retrospective study: we aim to investigate CKD and hypertension monitoring using administrative and health record data. We will also investigate the validity of CKD and hypertension administrative definitions in this population and the incidence of CKD and hypertension in the first ~10 years post-cancer therapy. We will investigate whether patient-, disease/treatment-, or system-specific factors modify these associations in both studies.

Limitations

Results from the prospective study may not be generalizable to non-high-risk CCS. The retrospective study is susceptible to surveillance bias.

Conclusions

Our team and knowledge translation plan is engaging patient partners, researchers, knowledge users, and policy group representatives. Our work will address international priorities to improve CCS health, provide the evidence of new disease burden and practice gaps to improve CCS guidelines, implement and test revised guidelines, plan trials to reduce CKD and hypertension, and improve long-term CCS health.

Cancer Risk and Mortality in Patients With Kidney Disease: A Population-Based Cohort Study

RATIONALE & OBJECTIVE

Patients with chronic kidney disease (CKD) may be at increased risk for cancer. CKD may also be associated with worse cancer outcomes. This study examined cancer incidence and mortality across the spectrum of CKD.

STUDY DESIGN

Population-based cohort study.

SETTING & PARTICIPANTS

All adult Ontario residents with data on estimated glomerular filtration rate (eGFR) or who were receiving maintenance dialysis or had received a kidney transplant (2007-2016).

EXPOSURE

Patients were categorized as of the first date they had 2 eGFR assessments or were registered as receiving maintenance dialysis or having received a kidney transplant. eGFR levels were further categorized as ≥60, 45-59, 30-44, 15-29, and <15 mL/min/1.73 m²; the latter 4 groups are consistent with KDIGO (Kidney Disease: Improving Global Outcomes) CKD categories G3a, G3b, G4, and G5, respectively.

OUTCOMES

Overall and site-specific cancer incidence and mortality.

ANALYTICAL APPROACH

Fine and Gray subdistribution hazard models.

RESULTS

Among 5,882,388 individuals with eGFR data, 29,809 receiving dialysis, and 4,951 having received a kidney transplant, there were 325,895 cancer diagnoses made during 29,993,847 person-years of follow-up. The cumulative incidence of cancer ranged between 10.8% and 15.3% in patients with kidney disease. Compared with patients with eGFR ≥60 mL/min/1.73 m², adjusted hazard ratios (AHRs) for a cancer diagnosis among patients with CKD G3a, G3b, G4, and G5 were 1.08 (95% CI, 1.07-1.10), 0.99 (95% CI, 0.97-1.01), 0.85 (95% CI, 0.81-0.88), and 0.81 (95% CI, 0.73-0.90), respectively. The AHRs for patients receiving dialysis and who had received a transplant were 1.01 (95% CI, 0.96-1.07) and 1.25 (95% CI, 1.12-1.39), respectively. Patients with kidney disease had higher proportions of stage 4 cancers at diagnosis. Patients with CKD G3a, G3b, and G4 and transplant recipients had increased risks of cancer-specific mortality (AHRs of 1.27 [95% CI, 1.23-1.32], 1.29 [95% CI, 1.24-1.35], 1.25 [95% CI, 1.18-1.33], and 1.48 [95% CI, 1.18-1.87], respectively). The risks of bladder and kidney cancers and multiple myeloma were particularly increased in CKD, and mortality from these malignancies increased with worsening kidney function.

LIMITATIONS

Possible unmeasured confounding and limited ability to infer causal associations.

CONCLUSIONS

Cancer incidence in the setting of kidney disease is substantial. Cancer risk was increased in mild to moderate CKD and among transplant recipients, but not in advanced kidney disease. Cancer-related mortality was significantly higher among patients with kidney disease, particularly urologic cancers and myeloma. Strategies to detect and manage these cancers in the CKD population are needed.

Multifaceted Intervention to Increase the Use of Home Dialysis: A Cluster Randomized Controlled Trial

BACKGROUND AND OBJECTIVES

Home dialysis therapies (peritoneal and home hemodialysis) are less expensive and provide similar outcomes to in-center hemodialysis, but they are underutilized in most health systems. Given this, we designed a multifaceted intervention to increase the use of home dialysis. In this study, our objective was to evaluate the effect of this intervention on home dialysis use in CKD clinics across Canada.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a cluster randomized controlled trial in 55 CKD clinic clusters in nine provinces in Canada between October 2014 and November 2015. Participants included all adult patients who initiated dialysis in the year following the intervention. We evaluated the implementation of a four-component intervention, which included phone surveys from a knowledge translation broker, a 1-year center-specific audit/feedback on home dialysis use, delivery of an educational package (including tools aimed at both providers and patients), and an academic detailing visit. The primary outcome was the proportion of patients using home dialysis at 180 days after dialysis initiation.

RESULTS

A total of 55 clinics were randomized (27 in the intervention and 28 in the control), with 5312 patients initiating dialysis in the 1-year follow-up period. In the primary analysis, there was no difference in the use of home dialysis at 180 days in the intervention and control clusters (absolute risk difference, 4%; 95% confidence interval, -2% to 10%). Using a difference-in-difference comparison, the use of home dialysis at 180 days was similar before and after implementation of the intervention (difference of 0% in intervention clinics; 95% confidence interval, -2% to 3%; difference of 0.8% in control clinics; 95% confidence interval, -1% to 3%; P=0.84).

CONCLUSIONS

A multifaceted intervention did not increase the use of home dialysis in adults initiating dialysis.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

A Cluster Randomized Trial to Assess the Impact of Patient and Provider Education on Use of Home Dialysis, NCT02202018.

Home versus In-Center Dialysis and Day of the Week Hospitalization: A Cohort Study

Background

The dialysis treatment day after the 2-day interdialytic interval (Monday/Tuesday) is associated with a heightened risk of hospitalization for patients on in-center hemodialysis (ICHD). In this national cohort study, we sought to characterize hospitalizations by day of the week for patients receiving ICHD, home HD (HHD), and peritoneal dialysis (PD) and to identify whether there were differences in the probability of a Monday/Tuesday admission for each modality type.

Methods

Patients on maintenance dialysis in Canada were analyzed from 2005 to 2014 using the Canadian Organ Replacement Register. Patients on hemodialysis were categorized as those receiving ICHD, HHD, frequent ICHD, or frequent HHD (the latter two included short daily and nocturnal HD). Hospitalizations were attributed to the previous treatment if they occurred within 30 days of a treatment change. Differences in the proportion of patients experiencing a Monday/Tuesday admission with all other days of the week were compared using a generalized linear model with binomial distribution and reported using adjusted odds ratios (OR) with 95% CIs.

Results

Overall, 27,430 individuals experienced 111,748 hospitalization episodes. Rates per 1000 patient days were 3.76, 2.98, 2.71, 2.16, and 2.13 for each of frequent ICHD, ICHD, PD, HHD, and frequent HHD, respectively. Compared with those on ICHD, only patients receiving frequent HHD (OR, 0.89; 95% CI, 0.81 to 0.97) and PD (OR, 0.95; 95% CI, 0.93 to 0.97) had a lower odds of experiencing a Monday/Tuesday admission. The OR was lower when restricted to hospitalization episodes for cardiovascular reasons comparing frequent HHD with ICHD (OR, 0.68; 95% CI, 0.48 to 0.96).

Conclusion

In this nationally representative cohort, we identified that the probability of a Monday/Tuesday admission was lower for frequent HHD and PD compared with ICHD, most notably for hospitalizations due to cardiovascular causes. Gaining a better understanding of the reasons behind this observation may help to develop future strategies to reduce overall and cause-specific hospitalization for patients receiving dialysis.

Simple compared to covariate-constrained randomization methods in balancing baseline characteristics: a case study of randomly allocating 72 hemodialysis centers in a cluster trial

Background and aim

Some parallel-group cluster-randomized trials use covariate-constrained rather than simple randomization. This is done to increase the chance of balancing the groups on cluster- and patient-level baseline characteristics. This study assessed how well two covariate-constrained randomization methods balanced baseline characteristics compared with simple randomization.

Methods

We conducted a mock 3-year cluster-randomized trial, with no active intervention, that started April 1, 2014, and ended March 31, 2017. We included a total of 11,832 patients from 72 hemodialysis centers (clusters) in Ontario, Canada. We randomly allocated the 72 clusters into two groups in a 1:1 ratio on a single date using individual- and cluster-level data available until April 1, 2013. Initially, we generated 1000 allocation schemes using simple randomization. Then, as an alternative, we performed covariate-constrained randomization based on historical data from these centers. In one analysis, we restricted on a set of 11 individual-level prognostic variables; in the other, we restricted on principal components generated using 29 baseline historical variables.

We created 300,000 different allocations for the covariate-constrained randomizations, and we restricted our analysis to the 30,000 best allocations based on the smallest sum of the penalized standardized differences. We then randomly sampled 1000 schemes from the 30,000 best allocations. We summarized our results with each randomization approach as the median (25th and 75th percentile) number of balanced baseline characteristics. There were 156 baseline characteristics, and a variable was balanced when the between-group standardized difference was ≤ 10%.

Results

The three randomization techniques had at least 125 of 156 balanced baseline characteristics in 90% of sampled allocations. The median number of balanced baseline characteristics using simple randomization was 147 (142, 150). The corresponding value for covariate-constrained randomization using 11 prognostic characteristics was 149 (146, 151), while for principal components, the value was 150 (147, 151).

Conclusion

In this setting with 72 clusters, constraining the randomization using historical information achieved better balance on baseline characteristics compared with simple randomization; however, the magnitude of benefit was modest.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05590-1.

Effects of a Knowledge-Translation Intervention on Early Dialysis Initiation: A Cluster Randomized Trial

BACKGROUND

The Initiating Dialysis Early and Late (IDEAL) trial, published in 2009, found no clinically measurable benefit with respect to risk of mortality or early complications with early dialysis initiation versus deferred dialysis start. After these findings, guidelines recommended an intent-to-defer approach to dialysis initiation, with the goal of deferring it until clinical symptoms arise.

METHODS

To evaluate a four-component knowledge translation intervention aimed at promoting an intent-to-defer strategy for dialysis initiation, we conducted a cluster randomized trial in Canada between October 2014 and November 2015. We randomized 55 clinics, 27 to the intervention group and 28 to the control group. The educational intervention, using knowledge-translation tools, included telephone surveys from a knowledge-translation broker, a 1-year center-specific audit with feedback, delivery of a guidelines package, and an academic detailing visit. Participants included adults who had at least 3 months of predialysis care and who started dialysis in the first year after the intervention. The primary efficacy outcome was the proportion of patients who initiated dialysis early (at eGFR >10.5 ml/min per 1.73 m²). The secondary outcome was the proportion of patients who initiated in the acute inpatient setting.

RESULTS

The analysis included 3424 patients initiating dialysis in the 1-year follow-up period. Of these, 509 of 1592 (32.0%) in the intervention arm and 605 of 1832 (33.0%) in the control arm started dialysis early. There was no difference in the proportion of individuals initiating dialysis early or in the proportion of individuals initiating dialysis as an acute inpatient.

CONCLUSIONS

A multifaceted knowledge translation intervention failed to reduce the proportion of early dialysis starts in patients with CKD followed in multidisciplinary clinics.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

ClinicalTrials.gov, NCT02183987. Available at: https://clinicaltrials.gov/ct2/show/NCT02183987.

Temporal Trends in Hemoglobin, Use of Erythropoiesis Stimulating Agents, and Major Clinical Outcomes in Incident Dialysis Patients in Canada

Introduction

Several jurisdictions have adopted a more conservative approach to anemia in patients receiving dialysis amid safety concerns from target hemoglobin studies. It is largely unknown if this has contributed to a change in clinical outcomes.

Methods

A national registry was used to identify 35,945 adult patients who initiated and were maintained on dialysis for ≥90 days in Canada from January 2007 to December 2015. Outcomes were ascertained until March 2017 via linkage with hospital discharge diagnoses. Cox proportional hazards models were used to investigate the association between the era of dialysis initiation and the primary composite outcome (acute myocardial infarction [AMI], stroke, or mortality).

Results

The mean hemoglobin at dialysis initiation decreased from 102.9 g/l in 2007 to 95.5 g/l in 2015, corresponding with a higher prevalence of hemoglobin <80 g/l (8% to 17%) and a reduction in erythropoiesis stimulating agent (ESA) use (49% to 44%). After multivariable adjustment, Era 3 (2013–2015) was associated with an 8% relative risk reduction in the primary outcome compared with Era 1 (2007–2009) (hazard ratio [HR] 0.92, 95% confidence interval [CI] 0.88–0.96), a 10% relative reduction in mortality (HR 0.90, 95% CI 0.85–0.94) but no significant change in AMI or stroke. In a model without era, neither hemoglobin nor ESA use was an independent predictor of outcome.

Conclusion

There have been modest declines in average hemoglobin values and ESA use among incident dialysis patients in Canada with no change in major cardiovascular outcomes. Patient survival has improved over time, likely for reasons other than anemia management.

Four steps to standardize reporting of peritoneal dialysis technique failure: A proposed approach

BACKGROUND

Technique failure is an important outcome measure in research and quality improvement in peritoneal dialysis (PD) programs, but there is a lack of consistency in how it is reported.

METHODS

We used data collected about incident dialysis patients from 10 Canadian dialysis programs between 1 January 2004 and 31 December 2018. We identified four main steps that are required when calculating the risk of technique failure. We changed one variable at a time, and then all steps, simultaneously, to determine the impact on the observed risk of technique failure at 24 months.

RESULTS

A total of 1448 patients received PD. Selecting different cohorts of PD patients changed the observed risk of technique failure at 24 months by 2%. More than one-third of patients who switched to hemodialysis returned to PD-90% returned within 180 days. The use of different time windows of observation for a return to PD resulted in risks of technique failure that differed by 16%. The way in which exit events were handled during the time window impacted the risk of technique failure by 4% and choice of statistical method changed results by 4%. Overall, the observed risk of technique failure at 24 months differed by 20%, simply by applying different approaches to the same data set.

CONCLUSIONS

The approach to reporting technique failure has an important impact on the observed results. We present a robust and transparent methodology to track technique failure over time and to compare performance between programs.

Dialysis Modality and Mortality in Heart Failure: A Retrospective Study of Incident Dialysis Patients

INTRODUCTION

Prior studies reported lower mortality with hemodialysis (HD) compared to peritoneal dialysis (PD) in patients with heart failure (HF). We examined mortality rate by initial dialysis modality in incident dialysis patients with a history of HF using contemporary data and methods that ensure comparable HD and PD groups.

METHODS

Retrospective cohort study using administrative databases in Ontario, Canada. Adults (age 50-80) with a history of HF who initiated maintenance dialysis between April 1, 2007 and March 31, 2016 were included. We excluded patients typically ineligible for PD as an initial modality (dialysis start in hospital, dementia, long-term care facility residency). We determined the cause-specific hazard ratio (transplant as a competing event) between initial dialysis modality (HD vs. PD) and all-cause mortality using an intention-to-treat approach.

RESULTS

We included 2,199 patients with HF who initiated maintenance dialysis (77% HD and 23% PD). There were 1,152 (67.8%) and 340 (68.1%) mortality events over a median follow-up of 2.4 and 2.5 years in the HD and PD groups, respectively. Patients initiating HD versus PD was not associated with the mortality rate (adjusted hazard ratio 1.0, 95% CI 0.9-1.1). Similar results were seen in analyses censoring at modality switches and treating modality as time-varying.

CONCLUSIONS

We found no difference in mortality by initial dialysis modality. Our data support the current practice of selecting dialysis modality based on patient preference for patients with pre-existing HF.

Cost-Utility of Dialysis in Canada: Hemodialysis, Peritoneal Dialysis, and Nondialysis Treatment of Kidney Failure

Rationale & Objective

The kidney failure population is growing, necessitating the expansion of dialysis programs. These programs are costly and require a substantial amount of health care resources. Tools that accurately forecast resource use can aid efficient allocation. The objective of this study is to describe the development of an economic simulation model that incorporates treatment history and detailed modality transitions for patients with kidney disease using real-world data to estimate associated costs, utility, and survival by initiating modality.

Study Design

Cost-utility model with microsimulation.

Setting & Population

Adult incident maintenance dialysis patients in Canada who initiated facility-based hemodialysis (HD) or home peritoneal dialysis (PD) between 2004 and 2013.

Intervention

HD and PD.

Outcomes

Costs (related to dialysis, transplantation, infections, and hospitalizations), survival, utility, and dialysis modality mix over time.

Model, Perspective, & Timeframe

The model took the perspective of the health care payer. Patients were followed up for 10 years from initiation of dialysis. Our cost-utility analysis compared the intervention with receiving no treatment.

Results

During a 10-year time horizon, the cost-utility ratio for all patients initiating dialysis was $103,779 per quality-adjusted life-year (QALY) in comparison to no treatment. Patients who initiated with facility-based HD were treated at a cost-utility ratio of $104,880/QALY and patients who initiated with home PD were treated at a cost-utility ratio of $83,762/QALY. During this time horizon, the total mean cost and QALYs per patient were estimated at $350,774 ± $204,704 and 3.38 ± 2.05) QALYs respectively.

Limitations

The results do not include costs from the societal perspective. Rare patient trajectories were unable to be assessed.

Conclusions

This model demonstrates that patients who initiated dialysis with PD were treated more cost-effectively than those who initiated with HD during a 10-year time horizon.

Home Hemodialysis and Peritoneal Dialysis Patient and Technique Survival in Canada

INTRODUCTION

As interest for home dialysis is growing, knowledge of comparative clinical outcomes between peritoneal dialysis (PD) and home hemodialysis (HHD) would help to better inform shared decision making with patients and caregivers during modality discussion. This study aimed to assess differences in risk of mortality and technique failure in an incident home dialysis cohort and, specifically, to assess change in this association through eras.

METHODS

All adults patients initiating PD or HHD, in Canada (excluding Quebec), within 365 days after kidney replacement therapy (KRT) initiation between 2000 and 2013 were included (administrative censoring 31 December 2014). Mortality and treatment failure (transfer to another modality for >90 days or death) were assessed in a multivariable Cox proportional hazard model, with prespecified stratification based on the year of KRT initiation.

RESULTS

The study included 959 HHD and 15,469 PD patients. Compared with incident PD, incident HHD was associated with a lower risk of mortality (adjusted hazard ratio [aHR] = 0.64, 95% confidence interval [CI] = 0.53-0.78), and treatment failure (aHR = 0.52, 95% CI = 0.45-0.60). These lower risks of mortality with HHD were more pronounced for older cohorts (2000-2005: aHR = 0.47, 95% CI = 0.31-0.70; 2006-2010: aHR = 0.70, 95% CI = 0.54-0.89) and not significantly different in the most recent era (2011-2013: aHR = 0.86, 95% CI = 0.51-1.47).

CONCLUSION

In Canadian incident KRT patients, HHD was associated with appreciably lower risks of mortality and treatment failure compared to PD, although this association appeared to be attenuated in the most contemporary era.

Contribution of medico-administrative data to the development of a comorbidity score to predict mortality in End-Stage Renal Disease patients

Comorbidity scores to predict mortality are very useful to facilitate decision-making for personalized patient management. This study aim was to assess the contribution of medico-administrative data in addition to French Renal Epidemiology and Information Network (REIN) data to the development of a risk score to predict the 1-year all-cause mortality in patients with End Stage Renal Disease (ESRD), and to compare it with previous scores. Data from a derivation sample (n = 6336 patients who started dialysis in 2015 in France) obtained by linking the REIN and the French National Health Insurance Information System databases were analyzed with multivariate Cox models to select risk factors to establish the score. A randomly chosen validation sample (n = 2716 patients who started dialysis in 2015) was used to validate the score and to compare it with the comorbidity indexes developed by Wright and Charlson. The ability to predict one-year mortality of the score constructed using REIN data linked to the medico-administrative database was not higher than that of the score constructed using only REIN data (i.e., Rennes score). The Rennes score included five comorbidities, albumin, and age. This score (AUC = 0.794, 95%CI: 0.768–0.821) outperformed both the Wright (AUC = 0.631, 95%CI: 0.621–0.639; p < 0.001) and Charlson (AUC = 0.703, 95%CI: 0.689–0.716; p < 0.001) indexes. Data from the REIN registry alone, collected at dialysis start, are sufficient to develop a risk score that can predict the one-year mortality in patients with ESRD. This simple score might help identifying high risk patients and proposing the most adapted care.

Association of Primary Care Involvement with Death or Hospitalizations for Patients Starting Dialysis

BACKGROUND AND OBJECTIVES

It is uncertain whether primary care physician continuity of care associates with a lower risk of death and hospitalization among patients transitioning to maintenance dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using provincial-linked administrative databases in Ontario, Canada, we conducted a population-based study of incident patients who initiated maintenance dialysis between 2005 and 2014 and survived for at least 90 days. We defined high primary care physician continuity as both a high usual provider of care index (where >75% of primary care physician visits occurred with the same primary care physician) in the 2 years before dialysis (an established measure of primary care physician continuity) and at least one visit with the same primary care physician in the 90 days after dialysis initiation. We used propensity scores to match a group of patients with high and low continuity so that indicators of baseline health were similar. The primary outcome was all-cause mortality, and secondary outcomes included all-cause and disease-specific hospitalizations during the 2 years after maintenance dialysis initiation.

RESULTS

We identified 19,099 eligible patients. There were 6612 patients with high primary care physician continuity, of whom 6391 (97%) were matched to 6391 patients with low primary care physician continuity. High primary care physician continuity was not associated with a lower risk of mortality (14.5 deaths per 100 person-years versus 15.2 deaths per 100 person-years; hazard ratio, 0.96; 95% confidence interval, 0.89 to 1.02). There was no difference in the rate of all-cause hospitalizations (hazard ratio, 0.96; 95% confidence interval, 0.92 to 1.01), and high primary care physician continuity was not associated with a lower risk of any disease-specific hospitalization, except for those related to diabetes (hazard ratio, 0.88; 95% confidence interval, 0.80 to 0.97).

CONCLUSIONS

High primary care physician continuity before and during the transition to maintenance dialysis was not associated with a lower risk of mortality or all-cause hospitalization.

Incidence of ESKD and Mortality among Children with Congenital Heart Disease after Cardiac Surgery

BACKGROUND AND OBJECTIVES

Survival after surgical repair for congenital heart disease has markedly improved; however, there are limited data on long-term ESKD and mortality during childhood.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted an observational, population-based cohort study of children who had their first surgery for congenital heart disease within 10 years of birth. The study was conducted in Ontario, Canada, where residents have universal access to health care services. Each child who underwent surgical repair was matched to ten children from the general population who were similar in age, sex, index date, rurality, and neighborhood income. Primary outcomes of all-cause mortality and ESKD were reported until March 2015.

RESULTS

We followed 3600 children with congenital heart disease for a median of 5.9 (interquartile range, 2.9-9.0) years after their surgical repair. Median age at first surgery was 150 (interquartile range, 40-252) days and 22% were low birth weight (<2500 g). During follow-up, 140 (4%) children who had surgery for congenital heart disease died and 52 (1%) reached ESKD. The cumulative incidence of death and ESKD at 1, 5, and 10 years was higher in children with surgical repair of congenital heart disease (death: 3%, 4%, and 5%, respectively; ESKD: 1%, 2%, and 2%, respectively) compared with the matched control population without any congenital heart disease (death: 0.06%, 0.10%, and 0.13%, respectively; ESKD: 0.00%, 0.02%, and 0.02%, respectively). The risk of ESKD and death increased with severity of congenital heart disease, with the highest risk in children with hypoplastic left heart syndrome and increased in children who had surgical repair of congenital heart disease compared with those without surgical repair.

CONCLUSIONS

The risk of mortality and ESKD is high in children who undergo surgical repair for congenital heart disease compared to the general population.

Validation of Self-Reported Race in a Canadian Provincial Renal Administrative Database

Background:

Administrative data are commonly used to study clinical outcomes in renal disease. Race is an important determinant of renal health delivery and outcomes in Canada but is not validated in most administrative data, and the correlation with census-based definitions of race is unknown.

Objectives:

Validation of self-reported race (SRR) in a Canadian provincial renal administrative database (Patient Records and Outcome Management Information System [PROMIS]) and comparison with the Canadian census categories of race.

Design:

Prospective patient survey study to validate SRR in PROMIS.

Setting:

British Columbia, Canada.

Patients:

Adult patients registered in PROMIS.

Measurements:

Survey SRR was used as gold standard to validate SRR in PROMIS. Self-reported race in PROMIS was compared with census race categories.

Methods:

This is a cross-sectional telephone survey of a random sample of all adults in PROMIS conducted between February 2016 and November 2016. Responders selected a race category from PROMIS and from the Canadian census. Sensitivity (Sn) and specificity (Sp) were calculated with 95% confidence intervals (CIs).

Results:

A total of 21 039 patients met inclusion criteria, 1677 were selected for the survey and 637 participated (38% response rate). There were no differences between the PROMIS, sampled, and responder populations. PROMIS SRR had an accuracy of 95.3% (95% CI: 94.2%-97.0%) when validated against the survey SRR with Sn and Sp ≥90% in all race groups except in Aboriginals (Sn 87.5%). The positive and negative predictive values were ≥95%, except in very low and high–prevalence groups, respectively. The Canadian census had an accuracy of 95.7% (95% CI: 94.4%-97.6%) when validated against PROMIS SRR with Sn and Sp ≥90%. The results did not differ in subgroups based on age, sex, birth outside Canada, or renal group (glomerulonephritis, chronic kidney disease, hemodialysis, peritoneal dialysis, transplant recipients, or live donors).

Limitations:

Analysis of minority groups and lower prevalence groups is limited by sample size. Results may not be generalizable to other administrative databases.

Conclusions:

We have shown high accuracy of PROMIS SRR that validates its use in the secondary analysis of administrative data for research. There is high correlation between PROMIS and census race categories which allows linkage with other data sources that use census-based definitions of race.

Association Between the Publication of the Initiating Dialysis Early and Late Trial and the Timing of Dialysis Initiation in Canada

IMPORTANCE

Published in 2010, the Initiating Dialysis Early and Late (IDEAL) randomized clinical trial, which randomized patients with an estimated glomerular filtration rate (GFR) between 10 and 15 mL/min/1.73 m2 to planned initiation of dialysis with an estimated GFR between 10 and 14 mL/min/1.73 m2 (early start) or an estimated GFR between 5 and 7 mL/min/1.73 m2 (late start), concluded that early initiation was not associated with improved survival or clinical outcomes.

OBJECTIVE

To assess the association between the IDEAL trial results and the proportion of early dialysis starts over time.

DESIGN, SETTING, AND PARTICIPANTS

This interrupted time series analysis used data from the Canadian Organ Replacement Register to study adult (≥18 years of age) patients with incident chronic dialysis between January 1, 2006, and December 31, 2015, in Canada, which has a universal health care system. Patients from the province of Quebec were excluded because its privacy laws preclude submission of deidentified data without first-person consent. The patients included in the study (n = 28 468) had at least 90 days of nephrologist care before starting dialysis and a recorded estimated GFR at dialysis initiation. Data analyses were performed from November 2016 to January 2019.

MAIN OUTCOMES AND MEASURES

The primary outcome was the proportion of early dialysis starts (estimated GFR >10.5 mL/min/1.73 m2), and the secondary outcomes included the proportions of acute inpatient dialysis starts, patients who started dialysis using a home modality, and patients receiving hemodialysis who started with an arteriovenous access. Measures included the trend prior to the IDEAL trial publication, the change in this trend after publication, and the immediate consequence of publication.

RESULTS

The final cohort comprised 28 468 patients, of whom 17 342 (60.9%) were male and the mean (SD) age was 64.8 (14.6) years. Before the IDEAL trial, a statistically significant increasing trend was observed in the monthly proportion of early dialysis starts (adjusted rate ratio, 1.002; 95% CI, 1.001-1.004; P = .004). After the IDEAL trial, an immediate decrease was observed in the proportion of early dialysis starts (rate ratio, 0.874; 95% CI, 0.818-0.933; P < .001), along with a statistically significant change in trend between the pretrial and posttrial periods (rate ratio, 0.994; 95% CI, 0.992-0.996; P < .001). No statistically significant differences were found in acute inpatient dialysis initiations, the proportion of patients receiving home dialysis as the initial modality, or the proportion of arteriovenous access creation at hemodialysis initiation after the IDEAL trial publication.

CONCLUSIONS AND RELEVANCE

The publication of the IDEAL trial appeared to be associated with an immediate and meaningful change in the timing of dialysis initiation in Canada.

A comparison of technique survival in Canadian peritoneal dialysis and home hemodialysis patients

Background

High discontinuation rates remain a challenge for home hemodialysis (HHD) and peritoneal dialysis (PD). We compared technique failure risks among Canadian patients receiving HHD and PD.

Methods

Using the Canadian Organ Replacement Register, we studied adult patients who initiated HHD or PD within 1 year of beginning dialysis between 2000 and 2012, with follow-up until 31 December 2013. Technique failure was defined as a transfer to any alternative modality for a period of ≥60 days. Technique survival between HHD and PD was compared using a Fine and Gray competing risk model. We also examined the time dependence of technique survival, the association of patient characteristics with technique failure and causes of technique failure.

Results

Between 2000 and 2012, 15 314 patients were treated with a home dialysis modality within 1 year of dialysis initiation: 14 461 on PD and 853 on HHD. Crude technique failure rates were highest during the first year of therapy for both home modalities. During the entire period of follow-up, technique failure was lower with HHD compared with PD (adjusted hazard ratio = 0.79; 95% confidence interval 0.69–0.90). However, the relative technique failure risk was not proportional over time and the beneficial association with HHD was only apparent after the first year of dialysis. Comparisons also varied among subgroups and the superior technique survival associated with HHD relative to PD was less pronounced in more recent years and among older patients. Predictors of technique failure also differed between modalities. While obesity, smoking and small facility size were associated with higher technique failure in both PD and HHD, the association with age and gender differed. Furthermore, the majority of discontinuation occurred for medical reasons in PD (38%), while the majority of HHD patients experienced technique failure due to social reasons or inadequate resources (50%).

Conclusions

In this Canadian study of home dialysis patients, HHD was associated with better technique survival compared with PD. However, patterns of technique failure differed significantly among these modalities. Strategies to improve patient retention across all home dialysis modalities are needed.

Comparing Five Comorbidity Indices to Predict Mortality in Chronic Kidney Disease: A Retrospective Cohort Study

Background:

Several different indices summarize patient comorbidity using health care data. An accurate index can be used to describe the risk profile of patients, and as an adjustment factor in analyses. How well these indices perform in persons with chronic kidney disease (CKD) is not well known.

Objective:

Assess the performance of 5 comorbidity indices at predicting mortality in 3 different patient groups with CKD: incident kidney transplant recipients, maintenance dialysis patients, and individuals with low estimated glomerular filtration rate (eGFR).

Design:

Population-based retrospective cohort study.

Setting:

Ontario, Canada, between 2004 and 2014.

Patients:

Individuals at the time they first received a kidney transplant, received maintenance dialysis, or were confirmed to have an eGFR less than 45 mL/min per 1.73m².

Measurements:

Five comorbidity indices: Charlson comorbidity index, end-stage renal disease-modified Charlson comorbidity index, Johns Hopkins’ Aggregated Diagnosis Groups score, Elixhauser score, and Wright-Khan index. Our primary outcome was 1-year all-cause mortality.

Methods:

Comorbidity indices were estimated using information in the prior 2 years. Each group was randomly divided 100 times into derivation and validation samples. Model discrimination was assessed using median c-statistics from logistic regression models, and calibration was evaluated graphically.

Results:

We identified 4111 kidney transplant recipients, 23 897 individuals receiving maintenance dialysis, and 181 425 individuals with a low eGFR. Within 1 year, 108 (2.6%), 4179 (17.5%), and 17 898 (9.9%) in each group had died, respectively. In the validation sample, model discrimination was inadequate with median c-statistics less than 0.7 for all 5 comorbidity indices for all 3 groups. Calibration was also poor for all models.

Limitations:

The study used administrative health care data so there is the potential for misclassification. Indices were modeled as continuous scores as opposed to indicators for individual conditions to limit overfitting.

Conclusions:

Existing comorbidity indices do not accurately predict 1-year mortality in patients with CKD. Current indices could be modified with additional risk factors to improve their performance in CKD, or a new index could be developed for this population.

End-Stage Kidney Disease in Patients With Autosomal Dominant Polycystic Kidney Disease: A 12-Year Study Based on the Canadian Organ Replacement Registry

Background:

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease, with afflicted patients often progressing to end-stage kidney disease (ESKD) requiring renal replacement therapy (RRT). As the timelines to ESKD are predictable over decades, it follows that ADPKD patients should be optimized regarding kidney transplantation, home dialysis therapies, and vascular access.

Objectives:

To examine the association of kidney transplantation, dialysis modalities, and vascular access in ADPKD patients compared with a matched, non-ADPKD cohort.

Setting:

Canadian patients from 2001-2012 excluding Quebec.

Patients:

All adult incident ESKD patients who received dialysis or a kidney transplant.

Measurements:

ADPKD as defined by the treating physician.

Methods:

ADPKD and non-ADPKD patients were propensity score (PS) matched (1:4) using demographics, comorbidities, and lab values. Conditional logistic regression and Cox proportional hazards models were used to examine associations with kidney transplantation (preemptive or any), dialysis modality (peritoneal, short daily, home, or in-center hemodialysis [HD]), vascular access (arteriovenous fistula [AVF], permanent or temporary central venous catheter [CVC]), and dialysis survival.

Results:

We matched 2120 ADPKD (99.9%) with 8283 non-ADPKD with no significant imbalances between the groups. ADPKD was significantly associated with preemptive kidney transplantation (odds ratio [OR] = 7.13, 95% confidence interval [CI] = 5.74-8.87), any kidney transplant (OR = 2.37, 95% CI = 2.14-2.63), and initial therapy of nocturnal daily HD (OR = 2.74, 95% CI = 1.38-5.44), whereas in-center intermittent HD was significantly less likely in the ADPKD population (OR = 0.59, 95% CI = 0.54-0.65). There was no difference in peritoneal dialysis (PD) as initial RRT but lower use of any PD among the ADPKD group (OR = 0.85, 95% CI = 0.77-0.95). ADPKD patients were significantly more likely to have an AVF (OR = 3.25, 95% CI = 2.79-3.79) and less likely to have either a permanent (OR 0.68, 95% CI 0.59-0.78) or temporary (OR = 0.49, 95% CI = 0.41-0.59) CVC as compared with the non-ADPKD cohort. Survival on either in-center HD or PD was better for ADPKD patients (HD: hazard ratio [HR] 0.48, 95% CI 0.44-0.53; PD: HR 0.73, 95% CI 0.60-0.88).

Limitations:

Conservative care patients were not captured; despite PS matching, the possibility of residual confounding remains.

Conclusions:

ADPKD patients were more likely to receive a kidney transplant, use home HD, dialyze with an AVF, and have better survival relative to non-ADPKD patients. Conversely, they were less likely to receive PD either as initial therapy or anytime during ESKD. This may be attributed to higher transplantation or clinical decision-making processes susceptible to education and intervention.

ESRD among Immigrants to Ontario, Canada: A Population-Based Study

Background The epidemiology of ESRD requiring maintenance dialysis (ESRD-D) in large, diverse immigrant populations is unclear.Methods We estimated ESRD-D prevalence and incidence among immigrants in Ontario, Canada. Adults residing in Ontario in 2014 were categorized as long-term Canadian residents or immigrants according to administrative health and immigration datasets. We determined ESRD-D prevalence among these adults and calculated age-adjusted prevalence ratios (PRs) comparing immigrants to long-term residents. Among those who immigrated to Ontario between 1991 and 2012, age-adjusted ESRD-D incidence was calculated by world region and country of birth, with immigrants from Western nations as the referent group.Results Among 1,902,394 immigrants and 8,860,283 long-term residents, 1700 (0.09%) and 8909 (0.10%), respectively, presented with ESRD-D. Age-adjusted ESRD-D prevalence was higher among immigrants from sub-Saharan Africa (PR, 2.17; 95% confidence interval [95% CI], 1.84 to 2.57), Latin America and the Caribbean (PR, 2.11; 95% CI, 1.90 to 2.34), South Asia (PR, 1.45; 95% CI, 1.32 to 1.59), and East Asia and the Pacific (PR, 1.34; 95% CI, 1.22 to 1.46). Immigrants from Somalia (PR, 4.18; 95% CI, 3.11 to 5.61), Trinidad and Tobago (PR, 2.88; 95% CI, 2.23 to 3.73), Jamaica (PR, 2.88; 95% CI, 2.40 to 3.44), Sudan (PR, 2.84; 95% CI, 1.53 to 5.27), and Guyana (PR, 2.69; 95% CI, 2.19 to 3.29) had the highest age-adjusted ESRD-D PRs relative to long-term residents. Immigrants from these countries also exhibited higher age-adjusted ESKD-D incidence relative to Western Nations immigrants.Conclusions Among immigrants in Canada, those from sub-Saharan Africa and the Caribbean have the highest ESRD-D risk. Tailored kidney-protective interventions should be developed for these susceptible populations.

Hospitalizations in Dialysis Patients in Canada: A National Cohort Study

Background:

Hospitalizations of chronic dialysis patients have not been previously studied at a national level in Canada. Understanding the scope and variables associated with hospitalizations will inform measures for improvement.

Objective:

To describe the risk of all-cause and infection-related hospitalizations in patients on dialysis.

Design:

Retrospective cohort study using health care administrative databases.

Setting:

Provinces and territories across Canada (excluding Manitoba and Quebec).

Patients:

Incident chronic dialysis patients with a dialysis start date between January 1, 2005, and March 31, 2014. Patients with a prior history of kidney transplantation were excluded.

Measurements:

Patient characteristics were recorded at baseline. Dialysis modality was treated as a time-varying covariate. The primary outcomes of interest were all-cause and dialysis-specific infection-related hospitalizations.

Methods:

Crude rates for all-cause hospitalization and infection-related hospitalization were determined per patient year (PPY) at 7 and 30 days, and at 3, 6, and 12 months postdialysis initiation. A stratified, gamma-distributed frailty model was used to assess repeat hospital admissions and to determine the inter-recurrence dependence of hospitalizations within individuals, as well as the hazard ratio (HR) attributed to each covariate of interest.

Results:

A total of 38 369 incident chronic dialysis patients were included: 38 088 adults and 281 pediatric patients (age less than 18 years). There were 112 374 hospitalizations, of which 11.5% were infection-related hospitalizations. The all-cause hospitalization rate was similar for all adult age groups (age 65 years and older: 1.40, 1.35, and 1.18 admissions PPY at 7 days, 30 days, and 6 months, respectively). The all-cause hospitalization rate was higher for pediatric patients (1.67, 2.48, and 2.47 admissions PPY at 7 days, 30 days, and 6 months, respectively; adjusted HR: 2.73, 95% confidence interval [CI]: 2.37-3.15, referent age group: 45-64 years). Within the first 7 days after dialysis initiation, patients on peritoneal dialysis had a higher risk of all-cause hospitalization (HR: 1.27, 95% CI: 1.07-1.50) and infection-related hospitalization (HR: 2.05, 95% CI: 1.19-3.55) compared with patients on hemodialysis. Beyond 7 days, the risk did not differ significantly by dialysis modality. Female sex and Indigenous race were significant risk factors for all-cause hospitalization.

Limitations:

The cohort had too few home hemodialysis patients to examine this subgroup. The outcome of infection-related hospitalization was determined using diagnostic codes. Dialysis patients from Manitoba and Quebec were not included.

Conclusions:

In Canada, the rates of hospitalization were not influenced by dialysis modality beyond the initial 7-day period following dialysis initiation; however, the rate of hospitalization in pediatric patients was higher than in adults at every time frame examined.

Racial Differences in Home Dialysis Utilization and Outcomes in Canada

BACKGROUND AND OBJECTIVES

Data on racial disparities in home dialysis utilization and outcomes are lacking in Canada, where health care is universally available.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We studied patients starting maintenance dialysis between 1996 and 2012 in the Canadian Organ Replacement Register, stratified by race: white, Asian, black, Aboriginal, Indian subcontinent, and other. The association between race and treatment with home dialysis was examined using generalized linear models. Secondary outcomes assessed racial differences in all-cause mortality and technique failure using a Fine and Gray competing risk model.

RESULTS

66,600 patients initiated chronic dialysis between 1996 and 2012. Compared with whites (n=46,092), treatment with home dialysis was lower among Aboriginals (n=3866; adjusted relative risk, RR, 0.71; 95% confidence interval, CI, 0.66 to 0.76) and higher in Asians (n=4157; adjusted RR, 1.28; 95% CI, 1.22 to 1.35) and others (n=2170; adjusted RR, 1.12; 95% CI, 1.04 to 1.20) but similar in blacks (n=2143) and subcontinent Indians (n=2809). Black (adjusted hazard ratio, HR, 1.31; 95% CI, 1.16 to 1.48) and Aboriginal (adjusted HR, 1.19; 95% CI, 1.06 to 1.33) patients treated with peritoneal dialysis had a significantly higher adjusted risk of technique failure compared with whites, whereas Asians had a lower risk (adjusted HR, 0.89; 95% CI, 0.82 to 0.99). In patients on peritoneal dialysis, the risk of death was significantly lower in Asians (adjusted HR, 0.83; 95% CI, 0.75 to 0.92), blacks (adjusted HR, 0.71; 95% CI, 0.59 to 0.85), and others (adjusted HR, 0.79; 95% CI, 0.68 to 0.92) but higher in Aboriginals (adjusted HR, 1.16; 95% CI, 1.02 to 1.32) compared with whites. Among patients on home hemodialysis, no significant racial differences in patient and technique survival were observed, which may be limited by the low number of events among each subgroups.

CONCLUSIONS

With the exception of Aboriginals, all racial minority groups in Canada were as likely to be treated with home dialysis compared with whites. However, significant racial differences exist in outcomes.

Knowledge Translation Interventions to Improve the Timing of Dialysis Initiation: Protocol for a Cluster Randomized Trial

Background:

Early initiation of chronic dialysis (starting dialysis with higher vs lower kidney function) has risen rapidly in the past 2 decades in Canada and internationally, despite absence of established health benefits and higher costs. In 2014, a Canadian guideline on the timing of dialysis initiation, recommending an intent-to-defer approach, was published.

Objective:

The objective of this study is to evaluate the efficacy and safety of a knowledge translation intervention to promote the intent-to-defer approach in clinical practice.

Design:

This study is a multicenter, 2-arm parallel, cluster randomized trial.

Setting:

The study involves 55 advanced chronic kidney disease clinics across Canada.

Patients:

Patients older than 18 years who are managed by nephrologists for more than 3 months, and initiate dialysis in the follow-up period are included in the study.

Measurements:

Outcomes will be measured at the patient-level and enumerated within a cluster. Data on characteristics of each dialysis start will be determined by linkages with the Canadian Organ Replacement Register. Primary outcomes include the proportion of patients who start dialysis early with an estimated glomerular filtration rate greater than 10.5 mL/min/1.73 m² and start dialysis in hospital as inpatients or in an emergency room setting. Secondary outcomes include the rate of change in early dialysis starts; rates of hospitalizations, deaths, and cost of predialysis care (wherever available); quarterly proportion of new starts; and acceptability of the knowledge translation materials.

Methods:

We randomized 55 multidisciplinary chronic disease clinics (clusters) in Canada to receive either an active knowledge translation intervention or no intervention for the uptake of the guideline on the timing of dialysis initiation. The active knowledge translation intervention consists of audit and feedback as well as patient- and provider-directed educational tools delivered at a comprehensive in-person medical detailing visit. Control clinics are only exposed to guideline release without active dissemination. We hypothesize that the clinics randomized to the intervention group will have a lower proportion of early dialysis starts.

Limitations:

Limitations include passive dissemination of the guideline through publication, and lead-time and survivor bias, which favors delayed dialysis initiation.

Conclusions:

If successful, this active knowledge translation intervention will reduce early dialysis starts, lead to health and economic benefits, and provide a successful framework for evaluating and disseminating future guidelines.

Trial Registration:

ClinicalTrials.gov, NCT02183987

Geographic and facility variation in initial use of non-tunneled catheters for incident maintenance hemodialysis patients

Background

Non-tunneled (temporary) hemodialysis catheters (NTHCs) are the least-optimal initial vascular access for incident maintenance hemodialysis patients yet little is known about factors associated with NTHC use in this context. We sought to determine factors associated with NTHC use and examine regional and facility-level variation in NTHC use for incident maintenance hemodialysis patients.

Methods

We analyzed registry data collected between January 2001 and December 2010 from 61 dialysis facilities within 12 geographic regions in Canada. Multi-level models and intra-class correlation coefficients were used to evaluate variation in NTHC use as initial hemodialysis access across facilities and geographic regions. Facility and patient characteristics associated with the lowest and highest quartiles of NTHC use were compared.

Results

During the study period, 21,052 patients initiated maintenance hemodialysis using a central venous catheter (CVC). This included 10,183 patients (48.3 %) in whom the initial CVC was a NTHC, as opposed to a tunneled CVC. Crude variation in NTHC use across facilities ranged from 3.7 to 99.4 % and across geographic regions from 32.4 to 85.1 %. In an adjusted multi-level logistic regression model, the proportion of total variation in NTHC use explained by facility-level and regional variation was 40.0 % and 34.1 %, respectively. Similar results were observed for the subgroup of patients who received greater than 12 months of pre-dialysis nephrology care. Patient-level factors associated with increased NTHC use were male gender, history of angina, pulmonary edema, COPD, hypertension, increasing distance from dialysis facility, higher serum phosphate, lower serum albumin and later calendar year.

Conclusions

There is wide variation in NTHC use as initial vascular access for incident maintenance hemodialysis patients across facilities and geographic regions in Canada. Identifying modifiable factors that explain this variation could facilitate a reduction of NTHC use in favor of more optimal initial vascular access.

Rehospitalizations and Emergency Department Visits after Hospital Discharge in Patients Receiving Maintenance Hemodialysis

Clinical outcomes after a hospital discharge are poorly defined for patients receiving maintenance in-center (outpatient) hemodialysis. To describe the proportion and characteristics of these patients who are rehospitalized, visit an emergency department, or die within 30 days after discharge from an acute hospitalization, we conducted a population-based study of all adult patients receiving maintenance in-center hemodialysis who were discharged between January 1, 2003, and December 31, 2011, from 157 acute care hospitals in Ontario, Canada. For patients with more than one hospitalization, we randomly selected a single hospitalization as the index hospitalization. Of the 11,177 patients included in the final cohort, 1926 (17%) were rehospitalized, 2971 (27%) were treated in the emergency department, and 840 (7.5%) died within 30 days of discharge. Complications of type 2 diabetes mellitus were the most common reason for rehospitalization, whereas heart failure was the most common reason for an emergency department visit. In multivariable analysis using a cause-specific Cox proportional hazards model, the following characteristics were associated with 30-day rehospitalization: older age, the number of hospital admissions in the preceding 6 months, the number of emergency department visits in the preceding 6 months, higher Charlson comorbidity index score, and the receipt of mechanical ventilation during the index hospitalization. Thus, a large proportion of patients receiving maintenance in-center hemodialysis will be readmitted or visit an emergency room within 30 days of an acute hospitalization. A focus on improving care transitions from the inpatient setting to the outpatient dialysis unit may improve outcomes and reduce healthcare costs.

Validation of kidney transplantation using administrative data

Background

Administrative data are increasingly being used to assess outcomes in kidney transplant recipients.

Objective

To assess the validity of transplant data in healthcare administrative databases compared to the reference standard of information collected directly from transplant centres.

Design

Retrospective cohort study.

Setting

One of three major transplant centres in Ontario (Toronto General Hospital, University Hospital – London, and Ottawa Hospital).

Patients

Recipients who received a kidney-only transplant between 2008 and 2011.

Measurements

For each data source, we identified kidney transplants performed. We calculated the sensitivity and positive predictive value (PPV) of the administrative data for the reference standard data.

Methods

The data collected from transplant centres were compared with data from the Canadian Organ Replacement Register (CORR) database, a hospital procedural code from the Canadian Institute for Health Information Discharge Abstract Database (CIHI-DAD), and provincial physician billing claims from the Ontario Health Insurance Plan (OHIP) database.

Results

During the study period, the three centres reported a total of 1112 kidney transplants performed. The probability of identifying kidney transplant recipients in CORR, CIHI, and OHIP, given they were identified by the transplant centres (sensitivity), was 96%, 98%, and 98% respectively. The probability that the database code correctly identified a transplant recipient (positive predictive value) in CORR, CIHI, and OHIP was 98%, 98%, and 96% respectively.

Limitations

We validated the information from 2008 to 2011 and cannot attest to the reliability of the data beyond the study period. Specifically, we would not regard this as evidence that applies to the earlier years, shortly after the inception of the databases. Secondly, we were unable to distinguish between first and repeat transplantation.

Conclusions

Codes in CORR, CIHI, and OHIP each operate well in the detection of kidney transplant recipients. These data sources can be used to efficiently identify and follow kidney transplant recipients for post-transplant outcomes.

Trends in Arteriovenous Fistula Use at Dialysis Initiation After Automated eGFR Reporting

The purpose of this study was to examine trends in the presence of an arteriovenous fistula (AVF) at dialysis initiation before and after eGFR reporting. All incident dialysis patients from four Canadian provinces that implemented province-wide, automated laboratory reporting of eGFR with known vascular access at dialysis initiation were included in the study (N = 25,201) from 2001 to 2010. The primary outcome was the change in proportion of patients with an AVF at dialysis initiation using an interrupted time series and adjusted multilevel logistic regression models. AVF usage at dialysis initiation decreased gradually over the study period from 19.0% to 14.6%. After implementation of automated eGFR reporting, there was attenuation in the decline in AVF usage in models adjusted for case-mix, facility, and the downward trajectory in AVF use over time. The adjusted odds ratio for initiating dialysis with an AVF 1 year post-eGFR reporting compared to pre-eGFR reporting was more pronounced in older patients (age tertile >73; OR: 1.40; 95% CI: 1.04-1.90). Laboratory-based eGFR reporting was associated with a possible attenuation in the decline of AVF at dialysis initiation and this was more pronounced in older patients.

Canadian Organ Replacement Register (CORR): reflecting the past and embracing the future

INTRODUCTION

The Canadian Organ Replacement Register (CORR) is the only Canadian information system on kidney and extra-kidney organ failure and transplantation in Canada. CORR's mandate is to record and analyze the level of activity and outcomes of vital organ transplantation and treatment of end stage kidney disease using dialysis, either hemodialysis or peritoneal dialysis, activities across Canada. The Canadian Organ Replacement Register was officially launched in 1987, and it included transplantation of extra-renal vital organs (liver, heart, lung, pancreas, bowel), in addition to renal transplantation and replacement therapy, with new financial support from the provinces.

OBJECTIVE

This manuscript describes the process of data acquisition and reporting, focusing on the patients with end stage kidney disease on dialysis, with data reported from the 2014 CORR Annual Data Report and the Center-Specific Reports on Clinical Measures.

METHODS

CORR is currently housed in the Canadian Institute for Health Information and collects data from hospital dialysis programs, regional transplant programs, organ procurement organizations and kidney dialysis services offered at independent health facilities. Data on patients is collected by completion of survey forms for each patient at the start of dialysis or receiving a transplant, using the Initial Registration form, and yearly follow up forms, which collects data on the status of the patient as of October 31(st).

RESULTS

The incident rate per million population (RPMP) has remained stable with the exception of the 65+ age group with has experience a modest decrease since 2001. However, there has been an increasing prevalence of ESKD diagnoses, with the highest rate per million population (RPMP) amongst the age group 65+ years. This is likely attributed to gradual improving patient survival. Between 2003 and 2012, nearly 90% of dialysis patients younger than <18 and 26% of patients 75+ years survived for at least five years.

CONCLUSION

As the number of people treated for end-stage organ failure grows, so does the importance of understanding their treatment and outcomes. In 2014, CORR continues to evolve and support the important information need to advance ESRD research and clinical practice.

Variation in the level of eGFR at dialysis initiation across dialysis facilities and geographic regions

BACKGROUND AND OBJECTIVES

The relative influence of facilities and regions on the timing of dialysis initiation remains unknown. The purpose of the study is to determine the variation in eGFR at dialysis initiation across dialysis facilities and geographic regions in Canada after accounting for patient-level factors (case mix).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In total, 33,263 dialysis patients with an eGFR measure at dialysis initiation between January of 2001 and December of 2010 representing 63 dialysis facilities and 14 geographic regions were included in the study. Multilevel models and intraclass correlation coefficients were used to evaluate the variation in timing of dialysis initiation by eGFR at the patient, facility, and geographic levels.

RESULTS

The proportion initiating dialysis with an eGFR≥10.5 ml/min per 1.73 m(2) was 35.3%, varying from 20.1% to 57.2% across geographic regions and from 10% to 67% across facilities. In an unadjusted, intercept-only linear model, 90.7%, 6.6%, and 2.7% of the explained variability were attributable to patient, facility, and geography, respectively. After adjustment for patient and facility factors, 96.9% of the explained variability was attributable to patient case mix, 3.1% was attributable to the facility, and 0.0% was attributable to the geographic region. These findings were consistent when the eGFR was categorized as a binary variable (≥10.5 ml/min per 1.73 m(2)) or in an analysis limited to patients with >3 months of predialysis care.

CONCLUSIONS

Patient characteristics accounted for the majority of the explained variation regarding the eGFR at the initiation of dialysis. There was a small amount of variation at the facility level and no variation among geographic regions that was independent of patient- and facility-level factors.

The three-year incidence of major hemorrhage among older adults initiating chronic dialysis

Background

For those who initiate chronic dialysis, knowing what proportion will experience 3-year outcomes of hemorrhage with hospitalization informs patient prognosis, disease impact, and the planning of trials and programs to prevent events.

Objectives

We examined the incidence of hemorrhage and related gastrointestinal endoscopic procedures in incident older dialysis patients and stratified patients by age, era, dialysis modality and whether recently prescribed anti-thrombotic medication.

Design

Retrospective cohort study

Setting

Ontario, Canada from 1998 to 2008 (n = 11,173)

Patients

All older patients (>65 years) who initiated chronic dialysis

Measurements

Hospitalization with hemorrhage and its subtypes (upper and lower gastrointestinal, intra-cerebral, subarachnoid) and related-gastrointestinal procedures.

Methods

Three-year outcomes of hospitalization with hemorrhage were expressed as cumulative incidence and incidence rate (number of events per 1,000 patient years). Results were stratified by patient age (66 to 74, 75 to 84, ≥ 85), era (1998 to 2001, 2002 to 2005, 2006 to 2008) and dialysis modality. Among those with hemorrhage, we examined prescriptions for anti-thrombotic medications (warfarin, clopidogrel) in the preceding 120 days.

Results

The 3-year cumulative incidence of hemorrhage was 14.4% (roughly 1 in 7 patients). By location, the 3-year cumulative incidence was 8.9% lower gastrointestinal, 6.1% upper gastrointestinal, 0.9% intra-cerebral and 0.1% sub arachnoid hemorrhage. The 3-year cumulative incidence of gastrointestinal endoscopic procedures was 14.8%. The cumulative incidence and rate of hemorrhage were not appreciably different across the 3 age strata, by era or by dialysis modality. Among patients with a hemorrhage, 29.5% were prescribed warfarin in the preceding 120 days, and 8.4% clopidogrel.

Limitations

Recurrent events were not included.

Conclusions

Many older patients who initiate chronic dialysis will be hospitalized with hemorrhage and receive related procedures over the subsequent three years. Despite greater age and co-morbidity over the last decade this incidence has not changed.

Electronic supplementary material

The online version of this article (doi:10.1186/s40697-014-0021-x) contains supplementary material, which is available to authorized users.

Mortality risk for women on chronic hemodialysis differs by age

Background

Previous reports have demonstrated similar survival for men and women on hemodialysis, despite women’s increased survival in the general population.

Objectives

To examine the effect of age on mortality in women undergoing chronic hemodialysis.

Design

A retrospective cohort study using an administrative data registry, the Canadian Organ Replacement Registry (CORR) from Jan. 2001 and Dec. 2009.

Setting

Canada.

Patients

28,971 (Women 11,792 (40.7%), Men 17,179 (59.3%)) incident chronic hemodialysis patients who survived greater than 90 days on dialysis.

Measurements

All-cause mortality.

Methods

Cox proportional hazards and competing risks models were employed to determine the independent association between sex, age and likelihood of all-cause mortality with renal transplantation as the competing outcome.

Results

During the study period, 6060 (51.4%) of women and 8650 (50.4%) of men initiating dialysis died. Younger women experienced higher mortality (Age < 45: Women 22.5%, Men 18.2%, hazard ratio (HR) 1.31 (1.12-1.52)) whereas elderly women experience lower mortality (Age 75–85: Women 65%, Men 67.3%, HR 0.94 95% CI 0.88-0.99, Age > 85: Women 66%, Men 70.2%, HR 0.83 95% CI 0.71-0.97) compared to men. This relationship persisted after accounting for the competing risk of transplantation.

Limitations

The cause of death was unknown.

Conclusions

Women’s survival on chronic hemodialysis varies by age compared to men with a significantly higher mortality in women younger than 45 years old and lower mortality in woman older than 75 years of age.

The association of eGFR reporting with the timing of dialysis initiation

Automated reporting of eGFR by laboratories has been widely implemented during the last decade. Over this same period, a steady increase in eGFR at dialysis initiation has been reported. This study examined trends in eGFR at dialysis initiation over time among incident dialysis patient populations before and after eGFR reporting. All patients who initiated dialysis between January of 2001 and December of 2010 in four Canadian provinces that implemented province-wide automated eGFR reporting and had an eGFR measure at dialysis initiation were included in the study (n=22,208). The primary outcome was change over time in eGFR among patients at dialysis initiation. An interrupted time series and adjusted multilevel regression models were used to determine the differences in eGFR at dialysis initiation before and after reporting. We observed a linear increase in the mean eGFR at dialysis initiation from 9.1 to 10.8 ml/min per m(2) during the study period. There was no change in the trajectory of the eGFR at dialysis initiation before or after eGFR reporting in crude or adjusted models accounting for case mix and facility characteristics. These findings were consistent among age and sex strata and when the proportions of patients with an eGFR≥10.5 or ≥12 ml/min per m(2) were examined. In conclusion, automated laboratory-based eGFR reporting did not influence eGFR at dialysis initiation among incident dialysis patient populations. Concerns that widespread eGFR reporting leads to earlier dialysis initiation are not supported by this study.

The association between geographic proximity to a dialysis facility and use of dialysis catheters

BACKGROUND

Residing remotely from health care resources appears to impact quality of care delivery. It remains unclear if there are differences in vascular access based on distance of one's residence to dialysis centre at time of dialysis initiation, and whether region or duration of pre-dialysis care are important effect modifiers.

METHODS

We studied the association of distance from a patients' residence to the nearest dialysis centre and central venous catheter (CVC) use in an observational study of 26,449 incident adult dialysis patients registered in the Canadian Organ Replacement Registry between 2000-2009. Multivariate logistic regression was used to assess the association between distance in tertiles and CVC use, adjusted for patient demographics and comorbidities. Geographic region and duration of pre-dialysis care were examined as potential effect modifiers.

RESULTS

Eighty percent of patients commenced dialysis with a CVC. Incident CVC use was highest among those living > 20 km from the dialysis centre (OR 1.29 (1.24-1.34)) compared to those living < 5 km from centre. The length of pre-dialysis care and geographic region were significant effect modifiers; among patients residing in the furthest tertile (>20 km) from the nearest dialysis centre, incident CVC use was more common with shorter length of pre-dialysis care (< 1 year) and residence in central regions of the country.

CONCLUSION

Residing further from a dialysis centre is associated with increased CVC use, an effect modified by shorter pre-dialysis care and the geographic region of the country. Efforts to reduce geographical disparities in pre dialysis care may decrease CVC use.

Geographic and facility-level variation in the use of peritoneal dialysis in Canada: a cohort study

BACKGROUND

Peritoneal dialysis is associated with similar survival and similar improvement in quality of life and is less costly compared with in-centre hemodialysis. We examined facility and geographic variation in the use of peritoneal dialysis in Canada.

METHODS

We analyzed data from the Canadian Organ Replacement Register for the period January 2001 to December 2010. We identified patients for whom peritoneal dialysis was the primary modality at 90 days after initiation of dialysis. We used multilevel models to evaluate variation in use of peritoneal dialysis by facility and geographic region.

RESULTS

We analyzed data for 31 778 incident dialysis patients at 56 facilities in 13 geographic regions across Canada. Use of peritoneal dialysis at 90 days varied considerably across geographic regions (range 19.8%-36.1%) and declined over time, from 28.8% in 2001 to 22.5% in 2010. After adjustment for case mix and facility-level quality indicators, 9.3% and 3.4% of the variability was attributable to facility and geographic factors, respectively. In adjusted models, there was a substantial difference between geographic regions with the lowest and highest peritoneal dialysis use (odds ratio for high use 1.51, 95% confidence interval [CI] 1.33-1.73 v. odds ratio for low use 0.69, 95% CI 0.60-0.79).

INTERPRETATION

In Canada, substantial variability in the use of peritoneal dialysis attributable to facility and geographic region was not explained by differences in patient case mix. An opportunity exists to optimize use of this cost-effective therapy through changes in policy and standardization of criteria for initiation of peritoneal dialysis.

Timing of peritoneal dialysis initiation and mortality: analysis of the Canadian Organ Replacement Registry

BACKGROUND

Several observational studies of hemodialysis patients show an association between early dialysis therapy initiation and increased mortality. Few studies have examined this association among peritoneal dialysis patients.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

A cohort of 8,047 incident peritoneal dialysis patients who started dialysis therapy in 2001-2009 and were treated in Canada.

PREDICTOR

Estimated glomerular filtration rate (eGFR) at dialysis therapy initiation. Defined early, mid, and late starts as eGFR>10.5, 7.5-10.5, and <7.5mL/min/1.73m(2), respectively.

OUTCOMES

Time to death.

MEASUREMENTS

Proportional piecewise exponential survival models to compare mortality (overall and early) for the 3 predictor groups.

RESULTS

Between 2001 and 2009, the proportion of patients starting peritoneal dialysis therapy as early starts increased from 29% (95% CI, 26%-32%) to 44% (95% CI, 41%-47%). Compared with the late-start group, the overall mortality rate was not higher for the early- (adjusted HR, 1.08; 95% CI, 0.96-1.23) or mid-start (adjusted HR, 0.96; 95% CI, 0.86-1.09) groups. However, when examined yearly, patients in the early-start group were significantly more likely to die within the first year of dialysis therapy compared with those in the late-start group (adjusted HR, 1.38; 95% CI, 1.10-1.73), but not in subsequent years.

LIMITATIONS

Bias and residual confounding may have influenced the observed relationship between predictor and outcome.

CONCLUSIONS

Patients are initiating peritoneal dialysis therapy at increasingly higher eGFRs. Contrary to most observational studies assessing hemodialysis, the early initiation of peritoneal dialysis therapy, at eGFR>10.5mL/min/1.73m(2), is not associated with increased mortality.

Validity of physician billing claims to identify deceased organ donors in large healthcare databases

Objective

We evaluated the validity of physician billing claims to identify deceased organ donors in large provincial healthcare databases.

Methods

We conducted a population-based retrospective validation study of all deceased donors in Ontario, Canada from 2006 to 2011 (n = 988). We included all registered deaths during the same period (n = 458,074). Our main outcome measures included sensitivity, specificity, positive predictive value, and negative predictive value of various algorithms consisting of physician billing claims to identify deceased organ donors and organ-specific donors compared to a reference standard of medical chart abstraction.

Results

The best performing algorithm consisted of any one of 10 different physician billing claims. This algorithm had a sensitivity of 75.4% (95% CI: 72.6% to 78.0%) and a positive predictive value of 77.4% (95% CI: 74.7% to 80.0%) for the identification of deceased organ donors. As expected, specificity and negative predictive value were near 100%. The number of organ donors identified by the algorithm each year was similar to the expected value, and this included the pre-validation period (1991 to 2005). Algorithms to identify organ–specific donors performed poorly (e.g. sensitivity ranged from 0% for small intestine to 67% for heart; positive predictive values ranged from 0% for small intestine to 37% for heart).

Interpretation

Primary data abstraction to identify deceased organ donors should be used whenever possible, particularly for the detection of organ-specific donations. The limitations of physician billing claims should be considered whenever they are used.

Nephrologist follow-up improves all-cause mortality of severe acute kidney injury survivors

Survivors of severe acute kidney injury remain at high risk of death well after apparent recovery from the initial insult. Here we determine whether early nephrology follow-up after a hospitalization complicated by severe acute kidney injury associates with patient survival. This consisted of a cohort study of all hospitalized adults in Ontario from 1996 to 2008 with acute kidney injury who received temporary inpatient dialysis and survived for 90 days following discharge independent from dialysis. Propensity scores were used to match individuals with early nephrology follow-up, defined as a visit with a nephrologist within 90 days of discharge, to those without. The outcome was time to all-cause mortality of 3877 patients who met the eligibility criteria within a maximum follow-up of 2 years. A total of 1583 patients had early nephrology follow-up of whom 1184 were successfully matched 1:1 to those not receiving early follow-up. The incidence of all-cause mortality was lower in those patients with early nephrology follow-up compared with those without (8.4 compared with 10.6 per 100-patient years, hazard ratio 0.76 (95% CI: 0.62-0.93)). Thus, early nephrology follow-up after hospitalization with acute kidney injury and temporary dialysis was associated with improved survival. This finding requires definitive testing in a randomized controlled trial.

Young aboriginals are less likely to receive a renal transplant: a Canadian national study

Background

Previous studies have demonstrated Aboriginals are less likely to receive a renal transplant in comparison to Caucasians however whether this applies to the entire population or specific subsets remains unclear. We examined the effect of age on renal transplantation in Aboriginals.

Methods

Data on 30,688 dialysis (Aboriginal 2,361, Caucasian 28, 327) patients obtained between Jan. 2000 and Dec. 2009 were included in the final analysis. Racial status was self-reported. Cox proportional hazards, the Fine and Grey sub-distribution method and Poisson regression were used to determine the association between race, age and transplantation.

Results

In comparison to Caucasians, Aboriginals were less likely to receive a renal transplant (Adjusted HR 0.66 95% CI 0.57-0.77, P < 0.0001) however after stratification by age and treating death as a competing outcome, the effect was more predominant in younger Aboriginals (Age 18–40: 20.6% aboriginals vs. 48.3% Caucasians transplanted; aHR 0.50(0.39-0.61), p < 0.0001, Age 41–50: 10.2% aboriginals vs. 33.9% Caucasians transplanted; aHR 0.46(0.32-0.64), p = 0.005, Age 51–60: 8.2% aboriginals vs. 19.5% Caucasians transplanted; aHR0.65(0.49-0.88), p = 0.01, Age >60: 2.7% aboriginals vs. 2.6% Caucasians transplanted; aHR 1.21(0.76-1.91), P = 0.4, Age X race interaction p < 0.0001). Both living and deceased donor transplants were lower in Aboriginals under the age of 60 compared to Caucasians.

Conclusion

Younger Aboriginals are less likely to receive a renal transplant compared to their Caucasian counterparts, even after adjustment for comorbidity. Determination of the reasons behind these discrepancies and interventions specifically targeting the Aboriginal population are warranted.

Early dialysis initiation and rates and timing of withdrawal from dialysis in Canada

BACKGROUND AND OBJECTIVES

The number of elderly patients and those with higher estimated GFR (eGFR) initiating dialysis have recently increased. This study sought to determine rates of withdrawal from dialysis and variables associated with withdrawal.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Canadian Organ Replacement Registry data were used to examine withdrawal rate and identify variables associated with withdrawal among the total cohort, patients age < 75 years, and patients age ≥ 75 years, along with those with early (eGFR > 10.5 ml/min per 1.73 m(2)) and those with late (eGFR ≤ 10.5 ml/min per 1.73 m(2)) initiation of dialysis, using a Cox proportional hazard model in patients starting dialysis between 2001 and 2009, with follow-up to December 31, 2009.

RESULTS

Median follow-up duration was 23.0 (interquartile range [IQR], 34.3) months. Rate of withdrawal per 100 patient-years doubled from 1.5 to 3.0, and withdrawal as cause of death increased from 7.9% to 19.5% between 2001 and 2009. Early initiation of dialysis was associated with increased withdrawal risk (hazard ratio, 1.17; 95% confidence interval, 1.06-1.30; P=0.002), as were older age, female sex, white race, and late referral to nephrologist. Patients age ≥ 75 years withdrew earlier after dialysis initiation (median, 15.9 [IQR, 27.9] months) compared to those age < 75 years (21.6 [IQR, 35.2] months). Early-start patients withdrew earlier (median, 15.6 [IQR, 28.5] months) compared with late-start patients (20.2 [IQR, 32.9] months).

CONCLUSIONS

In Canada, withdrawal from dialysis has increased significantly over recent years, especially among patients starting with higher eGFRs and in the elderly.

Survival and transplantation outcomes of children less than 2 years of age with end-stage renal disease

BACKGROUND

Young children with end-stage renal disease (ESRD) requiring renal replacement therapy (RRT) have traditionally experienced high rates of morbidity and mortality; however, detailed long-term follow-up data is limited.

METHODS

Using a population-based retrospective cohort with data from a national organ failure registry and administrative data from Canada's universal health care system, we analysed the outcomes of 87 children starting RRT (before age 2 years) and followed them until death or date of last contact [median follow-up 4.7 years, interquartile range (IQR) 1.4-9.8). We assessed secular trends in survival and the influence of: (1) age at start of RRT and (2) etiology of ESRD with survival and time to transplantation.

RESULTS

Patients were mostly male (69.0 %) with ESRD predominantly due to renal malformations (54.0 %). Peritoneal dialysis was the most common initial RRT (83.9 %). Fifty-seven (65.5 %) children received a renal transplant (median age at first transplant: 2.7 years, IQR 2.0-3.3). During 490 patient-years of follow-up, there were 23 (26.4 %) deaths, of which 22 occurred in patients who had not received a transplant. Mortality was greater for patients commencing dialysis between 1992 and 1999 and among the youngest children starting RRT (0-3 months). Children with ESRD secondary to renal malformations had better survival than those with ESRD due to other causes. Among the transplanted patients, all but one survived to the end of the observation period.

CONCLUSION

Children who start RRT before 3 months of age have a high risk of mortality. Among our paediatric patient cohort, mortality rates were much lower among children who had received a renal transplant.

Incidence and causes of end-stage renal disease among Aboriginal children and young adults

BACKGROUND

Although Aboriginal adults have a higher risk of end-stage renal disease than non-Aboriginal adults, the incidence and causes of end-stage renal disease among Aboriginal children and young adults are not well described.

METHODS

We calculated age- and sex-specific incidences of end-stage renal disease among Aboriginal people less than 22 years of age using data from a national organ failure registry. Incidence rate ratios were used to compare rates between Aboriginal and white Canadians. To contrast causes of end-stage renal disease by ethnicity and age, we calculated the odds of congenital diseases, glomerulonephritis and diabetes for Aboriginal people and compared them with those for white people in the following age strata: 0 to less than 22 years, 22 to less than 40 years, 40 to less than 60 years and older than 60 years.

RESULTS

Incidence rate ratios of end-stage renal disease for Aboriginal children and young adults (age < 22 yr, v. white people) were 1.82 (95% confidence interval [CI] 1.40-2.38) for boys and 3.24 (95% CI 2.60-4.05) for girls. Compared with white people, congenital diseases were less common among Aboriginal people aged less than 22 years (odds ratio [OR] 0.56, 95% CI 0.36-0.86), and glomerulonephritis was more common (OR 2.18, 95% CI 1.55-3.07). An excess of glomerulonephritis, but not diabetes, was seen among Aboriginal people aged 22 to less than 40 years. The converse was true (higher risk of diabetes, lower risk of glomerulonephritis) among Aboriginal people aged 40 years and older.

INTERPRETATION

The incidence of end-stage renal disease is higher among Aboriginal children and young adults than among white children and young adults. This higher incidence may be driven by an increased risk of glomerulonephritis in this population.