Expanding Access to High KDPI Kidney Transplant for Recipients Aged 60 y and Older: Cost Utility and Survival

Background

Modern organ allocation systems are tasked with equitably maximizing the utility of transplanted organs. Increasing the use of deceased donor organs at risk of discard may be a cost-effective strategy to improve overall transplant benefit. We determined the survival implications and cost utility of increasing the use of marginal kidneys in an older adult Canadian population of patients with end-stage kidney disease.

Methods

We constructed a cost-utility model with microsimulation from the perspective of the Canadian single-payer health system for incident transplant waitlisted patients aged 60 y and older. A kidney donor profile index score of ≥86 was considered a marginal kidney. Donor- and recipient-level characteristics encompassed in the kidney donor profile index and estimated posttransplant survival scores were used to derive survival posttransplant. Patients were followed up for 10 y from the date of waitlist initiation. Our analysis compared the routine use of marginal kidneys (marginal kidney scenario) with the current practice of limited use (status quo scenario).

Results

The 10-y mean cost and quality-adjusted life-years per patient in the marginal kidney scenario were estimated at $379 485.33 (SD: $156 872.49) and 4.77 (SD: 1.87). In the status quo scenario, the mean cost and quality-adjusted life-years per patient were $402 937.68 (SD: $168 508.85) and 4.37 (SD: 1.87); thus, the intervention was considered dominant. At 10 y, 62.8% and 57.0% of the respective cohorts in the marginal kidney and status quo scenarios remained alive.

Conclusions

Increasing the use of marginal kidneys in patients with end-stage kidney disease aged 60 y and older may offer cost savings, improved quality of life, and greater patient survival in comparison with usual care.

A Predictive Model for Kidney Failure After Nephrectomy for Localized Kidney Cancer: The Kidney Cancer Risk Equation

RATIONALE & OBJECTIVE

Nephrectomy is the mainstay of treatment for individuals with localized kidney cancer. However, surgery can potentially result in the loss of kidney function or in kidney failure requiring dialysis/kidney transplantation. There are currently no clinical tools available to preoperatively identify which patients are at risk of kidney failure over the long term. Our study developed and validated a prediction equation for kidney failure after nephrectomy for localized kidney cancer.

STUDY DESIGN

Population-level cohort study.

SETTING & PARTICIPANTS

Adults (n=1,026) from Manitoba, Canada, with non-metastatic kidney cancer diagnosed between January 1, 2004, and December 31, 2016, who were treated with either a partial or radical nephrectomy and had at least 1 estimated glomerular filtration rate (eGFR) measurement before and after nephrectomy. A validation cohort included individuals in Ontario (n=12,043) with a diagnosis of localized kidney cancer between October 1, 2008, and September 30, 2018, who received a partial or radical nephrectomy and had at least 1 eGFR measurement before and after surgery.

NEW PREDICTORS & ESTABLISHED PREDICTORS

Age, sex, eGFR, urinary albumin-creatinine ratio, history of diabetes mellitus, and nephrectomy type (partial/radical).

OUTCOME

The primary outcome was a composite of dialysis, transplantation, or an eGFR<15mL/min/1.73m2 during the follow-up period.

ANALYTICAL APPROACH

Cox proportional hazards regression models evaluated for accuracy using area under the receiver operating characteristic curve (AUC), Brier scores, calibration plots, and continuous net reclassification improvement. We also implemented decision curve analysis. Models developed in the Manitoba cohort were validated in the Ontario cohort.

RESULTS

In the development cohort, 10.3% reached kidney failure after nephrectomy. The final model resulted in a 5-year area under the curve of 0.85 (95% CI, 0.78-0.92) in the development cohort and 0.86 (95% CI, 0.84-0.88) in the validation cohort.

LIMITATIONS

Further external validation needed in diverse cohorts.

CONCLUSIONS

Our externally validated model can be easily applied in clinical practice to inform preoperative discussions about kidney failure risk in patients facing surgical options for localized kidney cancer.

PLAIN-LANGUAGE SUMMARY

Patients with localized kidney cancer often experience a lot of worry about whether their kidney function will remain stable or will decline if they choose to undergo surgery for treatment. To help patients make an informed treatment decision, we developed a simple equation that incorporates 6 easily accessible pieces of patient information to predict the risk of reaching kidney failure 5 years after kidney cancer surgery. We expect that this tool has the potential to inform patient-centered discussions tailored around individualized risk, helping ensure that patients receive the most appropriate risk-based care.

Association of body mass index with the development of metabolic acidosis in patients with chronic kidney disease

AIMS

Higher body mass index (BMI) is associated with higher bone mass and bone serves as a buffer during the development of metabolic acidosis. The authors sought to examine the relationship between BMI and metabolic acidosis in patients with chronic kidney disease (CKD).

MATERIALS AND METHODS

The study utilized a large US longitudinal data repository including over 103 million patients from healthcare provider organizations to evaluate the relationship between the exposure variable (BMI) and the prevalence and incidence of metabolic acidosis among patients with estimated glomerular filtration rate <60 ml/min/1.73 m2. Incident metabolic acidosis was identified at the first of two consecutive post-index serum bicarbonate values, 10-365 days apart, between 12 and <22 mEq/L in patients with normal index serum bicarbonate. Cox proportional hazard models were adjusted for multiple variables including demographics, comorbidities, income, education, and kidney function.

RESULTS

103,766 patients qualified for this study; 6472 (6.2%) had metabolic acidosis at index. An inverse association between BMI category and metabolic acidosis was observed for both baseline (prevalence) and new-onset (incidence) metabolic acidosis. Compared to BMI category of 18.5 to <25 kg/m2, each category of incrementally higher BMI was associated with a decreasing risk of incident metabolic acidosis; the adjusted hazard ratios (95% confidence interval) were 0.866 (0.824-0.911), 0.770 (0.729-0.813), 0.664 (0.622-0.709), and 0.612 (0.571-0.655) for BMI 25 to <30, 30 to <35, 35 to <40, and 40+ kg/m2, respectively.

CONCLUSIONS

Among patients with CKD, an incremental increase in BMI was inversely associated with both the prevalence and incidence of metabolic acidosis. These associations suggest that increased body weight may protect against the development of metabolic acidosis, a risk factor for progressive loss of kidney function.

Practical Utilization of Prediction Equations in Chronic Kidney Disease

Chronic kidney disease (CKD) is common and can lead to kidney failure, cardiovascular complications, and early mortality. While nephrologists can provide valuable insights for patients at all stages of CKD, these scarce resources should be targeted at patients with the highest risk of progression and adverse outcomes. Prediction models are tools that can help providers risk stratify patients if they are effectively implemented into the clinical workflow. We believe these equations should demonstrate (1) clinical utility: where they can provide useful information to the physician and patients; and (2) clinical usability: where they are able to be easily integrated into clinical workflow and do not result in unnecessary costs or visits. CKD often remains unrecognized until later stages when a large window of opportunity to delay progression has already passed. Models to determine progression of CKD using thresholds such as a 40% decline in eGFR can provide clinical utility in risk stratifying patients at all stages of CKD, an endpoint that has been recommended by the FDA for the evaluation of drug approvals for disease-modifying therapies. For patients at more advanced stages of CKD with a greater risk of kidney failure, tools such as the kidney failure risk equation can be implemented to help guide most costly decisions, such as referral to multidisciplinary care, commencing dialysis modality education, or planning for vascular access placement surgery. In addition, models focused on determining outcomes following dialysis initiation can help inform shared decision-making between patient and provider to better inform decisions around conservative care. To ensure widespread adoption of these tools, it is important to ensure that they are broadly generalizable to many health settings and easily implemented into existing clinic workflows with minimum disruption.

Increasing Serum Bicarbonate is Associated with Reduced Risk of Adverse Kidney Outcomes in Patients with CKD and Metabolic Acidosis

Introduction

Low serum bicarbonate at a single point in time is associated with accelerated kidney decline in patients with chronic kidney disease (CKD). We modeled how changes in serum bicarbonate over time affect incidence of adverse kidney outcomes.

Methods

We analyzed data from Optum's deidentified Integrated Claims-Clinical data set of US patients (2007-2019) with ≥1 year of prior medical record data, CKD stages G3 to G5, and metabolic acidosis (i.e., index serum bicarbonate 12 to <22 mmol/l). The primary predictor of interest was the change in serum bicarbonate, evaluated at each postindex outpatient serum bicarbonate test as a time-dependent continuous variable. The primary outcome was a composite of either a ≥40% decline in estimated glomerular filtration rate (eGFR) from index or evidence of dialysis or transplantation, evaluated using Cox proportional hazards models.

Results

A total of 24,384 patients were included in the cohort with median follow-up of 3.7 years. A within-patient increase in serum bicarbonate over time was associated with a lower risk of the composite kidney outcome. The unadjusted hazard ratio (HR) per 1-mmol/l increase in serum bicarbonate was 0.911 (95% confidence interval [CI]: 0.905-0.917; P < 0.001). After adjustment for baseline eGFR and serum bicarbonate, the time-adjusted effect of baseline eGFR and other covariates, the HR per 1-mmol/l increase in serum bicarbonate was largely unchanged (0.916 [95% CI: 0.910-0.922; P < 0.001]).

Conclusion

In a real-world population of US patients with CKD and metabolic acidosis, a within-patient increase in serum bicarbonate over time independent of changes in eGFR, was associated with a lower risk of CKD progression.

A Machine Learning Model to Predict Diuretic Resistance

BACKGROUND

Volume overload is a common complication encountered in hospitalized patients, and the mainstay of therapy is diuresis. Unfortunately, the diuretic response in some individuals is inadequate despite a typical dose of loop diuretics, a phenomenon called diuretic resistance. An accurate prediction model that predicts diuretic resistance using predosing variables could inform the right diuretic dose for a prospective patient.

METHODS

Two large, deidentified, publicly available, and independent intensive care unit (ICU) databases from the United States were used-the Medical Information Mart for Intensive Care III (MIMIC) and the Philips eICU databases. Loop diuretic resistance was defined as <1400 ml of urine per 40 mg of diuretic dose in 24 hours. Using 24-hour windows throughout admission, commonly accessible variables were obtained and incorporated into the model. Data imputation was performed using a highly accurate machine learning method. Using XGBoost, several models were created using train and test datasets from the eICU database. These were then combined into an ensemble model optimized for increased specificity and then externally validated on the MIMIC database.

RESULTS

The final ensemble model was composed of four separate models, each using 21 commonly available variables. The ensemble model outperformed individual models during validation. Higher serum creatinine, lower systolic blood pressure, lower serum chloride, higher age, and female sex were the most important predictors of diuretic resistance (in that order). The specificity of the model on external validation was 92%, yielding a positive likelihood ratio of 3.46 while maintaining overall discrimination (C-statistic 0.69).

CONCLUSIONS

A diuretic resistance prediction model was created using machine learning and was externally validated in ICU populations. The model is easy to use, would provide actionable information at the bedside, and would be ready for implementation in existing electronic medical records. This study also provides a framework for the development of future machine learning models.

Metabolic acidosis is undertreated and underdiagnosed: a retrospective cohort study

Background

Guidelines recommend treatment of metabolic acidosis (MA) in patients with chronic kidney disease (CKD), but diagnosis and treatment rates in real-world settings are unknown. We investigated the frequency of MA treatment and diagnosis in patients with CKD.

Methods

In this retrospective cohort study, we examined administrative health data from 2 US databases (Optum's de-identified Integrated Claims + Clinical Electronic Health Record Database (US EMR cohort; January 1, 2007 to June 30, 2019) and Symphony Health Solutions IDV® (US Claims cohort; May 1, 2016 to April 30, 2019)) and population-level databases from Manitoba, Canada (April 1, 2006 to March 31, 2018). Patients who met laboratory criteria indicative of CKD and chronic MA were included: 2 consecutive estimated glomerular filtration (eGFR) results &lt;60 mL/min/1.73 m2 and 2 serum bicarbonate results 12 to &lt;22 mEq/L over 28–365 days. Outcomes included treatment of MA (defined as a prescription for oral sodium bicarbonate) and a diagnosis of MA (defined using administrative records). Outcomes were assessed over a 3-year period (1 year pre-index, 2 years post-index).

Results

A total of 96 184 patients were included: US EMR, 6179; Manitoba 3223; US Claims, 86 782. Sodium bicarbonate treatment was prescribed for 17.6%, 8.7%, and 15.3% of patients, and a diagnosis was found for 44.7%, 20.9%, and 20.9% of patients, for the US EMR, Manitoba and US Claims cohorts, respectively.

Conclusions

This analysis of 96 184 patients with laboratory-confirmed MA from 3 independent cohorts of patients with CKD and MA highlights an important diagnosis and treatment gap for this disease-modifying complication.

Metabolic Acidosis is Associated With Acute Kidney Injury in Patients With CKD

Introduction

Metabolic acidosis in patients with chronic kidney disease (CKD) results from a loss of kidney function. It has been associated with CKD progression, all-cause mortality, and other adverse outcomes. We aimed to determine whether metabolic acidosis is associated with a higher risk of acute kidney injury (AKI).

Methods

This was a retrospective cohort study. Using electronic health records and administrative data, we enrolled 2 North American cohorts of patients with CKD Stages G3-G5 as follows: (i) 136,067 patients in the US electronic medical record (EMR) based cohort; and (ii) 34,957 patients in the Manitoba claims-based cohort. The primary exposure was metabolic acidosis (serum bicarbonate between 12 mEq/l and <22 mEq/l). The primary outcome was the development of AKI (defined using ICD-9 and 10 codes at hospital admission or a laboratory-based definition based on Kidney Disease: Improving Global Outcomes guidelines). We applied Cox proportional hazards regression models adjusting for relevant demographic and clinical characteristics.

Results

In both cohorts, metabolic acidosis was associated with AKI: hazard ratio (HR) 1.57 (95% confidence interval [CI] 1.52-1.61) in the US EMR cohort, and HR 1.65 (95% CI 1.58-1.73) in the Manitoba claims cohort. The association was consistent when serum bicarbonate was treated as a continuous variable, and in multiple subgroups, and sensitivity analyses including those adjusting for albuminuria.

Conclusion

Metabolic acidosis is associated with a higher risk of AKI in patients with CKD. AKI should be considered as an outcome in studies of treatments for patients with metabolic acidosis.

Role of artificial intelligence in the diagnosis and management of kidney disease: applications to chronic kidney disease and acute kidney injury

PURPOSE OF REVIEW

Chronic kidney disease (CKD) and acute kidney injury (AKI) are global public health problems associated with a significant burden of morbidity, healthcare resource use, and all-cause mortality. This review explores recently published studies that take a machine learning approach to the diagnosis, management, and prognostication in patients with AKI or CKD.

RECENT FINDINGS

The release of novel therapeutics for CKD has highlighted the importance of accurately identifying patients at the highest risk of progression. Many models have been constructed with reasonable predictive accuracy but have not been extensively externally validated and peer reviewed. Similarly, machine learning models have been developed for prediction of AKI and have found sufficient accuracy. There are issues to implementing these models, however, with conflicting results with respect to the relationship between prediction of an AKI outcome and improvements in the occurrence of other adverse events, and in some circumstances potential harm.

SUMMARY

Artificial intelligence models can help guide management of CKD and AKI, but it is important to ensure that they are broadly applicable and generalizable to various settings and associated with improved clinical decision-making and outcomes.

Association of metabolic acidosis with fractures, falls, protein-calorie malnutrition, and failure to thrive in patients with chronic kidney disease

Background

The risk of adverse geriatric outcomes such as falls and fractures is high among patients with chronic kidney disease (CKD). Metabolic acidosis is associated with protein catabolism and bone loss in experimental animal and human studies. We sought to quantify the independent association of metabolic acidosis with adverse muscle, bone, and functional outcomes in a large U.S. community-based cohort.

Methods

The Optum's de-identified Integrated Claims-Clinical dataset of US patients (2007-2017) was used to generate a cohort of patients with non-dialysis-dependent CKD who had eGFR &gt;10 to &lt;60 mL/min/1.73 m2 and 2 serum bicarbonate values 12 to &lt;22 mmol/L or 22-29 mmol/L. The primary outcomes were failure to thrive, protein-calorie malnutrition, and fall or fracture. Cox proportional hazards models were used for the primary outcomes for up to 10 years, while logistic regression models were used at 2 years.

Results

51,558 patients qualified for the study, with a median (IQR) follow-up time of 4.2 (2.5-5.8) years. Over a ≤ 10-year period, for each 1-mmol/L increase in serum bicarbonate, the hazard ratios (adjusted for age, sex, race, eGFR, serum albumin, hemoglobin, diabetes and cardiovascular comorbidities) for failure to thrive, protein-calorie malnutrition, and fall or fracture were 0.91 (95% confidence interval [CI], 0.90-0.92), 0.91 (95% CI, 0.90-0.92), and 0.95 (95% CI, 0.95-0.96), all P &lt; 0.001, respectively.

Conclusions

The presence and severity of metabolic acidosis was a significant, independent risk factor for failure to thrive, protein-calorie malnutrition, and fall or fracture in this large community cohort of patients with stage 3-5 CKD.

Cost of the quanta SC+ hemodialysis system for self-care in the United Kingdom

Introduction

New personal hemodialysis systems, such as the quanta SC+, are being developed; these systems are smaller and simpler to use while providing the clearances of conventional systems. Increasing the uptake of lower‐intensity assistance and full self‐care dialysis may provide economic benefits to the public health payer. In the United Kingdom, most hemodialysis patients currently receive facility‐based dialysis costing more than £36,350 per year including patient transport. As such, we aimed to describe the annual costs of using the SC+ hemodialysis system in the United Kingdom for 3×‐weekly and 3.5×‐weekly dialysis regimens, for self‐care hemodialysis provided both in‐center and at home.

Methods

We applied a cost minimization approach. Costs for human resources, equipment, and consumables were sourced from the dialysis machine developer (Quanta Dialysis Technologies) based upon discussions with dialysis providers. Facility overhead expenses and transport costs were taken from a review of the literature.

Findings

Annual costs associated with the use of the SC+ hemodialysis system were estimated to be £26,642 for hemodialysis provided 3× weekly as home self‐care; £30,235 for hemodialysis provided 3× weekly as self‐care in‐center; £29,866 for hemodialysis provided 3.5× weekly as home self‐care; and £36,185 for hemodialysis provided 3.5× weekly as self‐care in‐center.

Discussion

We found that the SC+ hemodialysis system offers improved cost‐effectiveness for both 3×‐weekly and 3.5×‐weekly self‐care dialysis performed at home or as self‐care in‐center versus fully assisted dialysis provided 3× weekly with conventional machines in facilities.

Kidney Failure Risk Equation and Cost of Care in Patients with Chronic Kidney Disease

BACKGROUND AND OBJECTIVES

Patients with CKD exhibit heterogeneity in their rates of progression to kidney failure. The kidney failure risk equation (KFRE) has been shown to accurately estimate progression to kidney failure in adults with CKD. Our objective was to determine health care utilization patterns of patients on the basis of their risk of progression.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective cohort study of adults with CKD and eGFR of 15-59 ml/min per 1.73 m² enrolled in multidisciplinary CKD clinics in the province of Saskatchewan, Canada. Data were collected from January 1, 2004 to December 31, 2012 and followed for 5 years (December 31, 2017). We stratified patients by eGFR and risk of progression and compared the number and cost of hospital admissions, physician visits, and prescription drugs.

RESULTS

In total, 1003 adults were included in the study. Within the eGFR of 15-29 ml/min per 1.73 m² group, the costs of hospital admissions, physician visits, and drug dispensations over the 5-year study period comparing high-risk patients with low-risk patients were (Canadian dollars) $89,265 versus $48,374 (P=0.008), $23,423 versus $11,231 (P<0.001), and $21,853 versus $16,757 (P=0.01), respectively. Within the eGFR of 30-59 ml/min per 1.73 m² group, the costs of hospital admissions, physician visits, and prescription drugs were $55,944 versus $36,740 (P=0.10), $13,414 versus $10,370 (P=0.08), and $20,394 versus $14,902 (P=0.02) in high-risk patients in comparison with low-risk patients, respectively, for progression to kidney failure.

CONCLUSIONS

In patients with CKD and eGFR of 15-59 ml/min per 1.73 m² followed in multidisciplinary clinics, the costs of hospital admissions, physician visits, and drugs were higher for patients at higher risk of progression to kidney failure by the KFRE compared with patients in the low-risk category. The high-risk group of patients with CKD and eGFR of 15-29 ml/min per 1.73 m² had stronger association with hospitalizations costs, physician visits, and drug utilizations.

Costs of Assisted Home Dialysis: A Single-Payer Canadian Model From Manitoba

Rationale & Objective

The prevalence of kidney failure is increasing globally. Most of these patients will require life-sustaining dialysis at a substantial cost to the health care system. Assisted peritoneal dialysis (PD) and assisted home hemodialysis (HD) are potential alternatives to in-center HD and have demonstrated equivalent outcomes with respect to mortality and morbidity. We aim to describe the costs associated with assisted continuous cycling PD (CCPD) and assisted home HD.

Study Design

Cost minimization model.

Setting & Population

Adult incident maintenance dialysis patients in Manitoba, Canada.

Intervention

Full- and partial-assist home HD and CCPD. Full-assist modalities were defined as nurse-assisted dialysis setup and takedown performed by a health care aide, whereas partial-assist modalities only included nurse-assisted setup. Additionally, full-assist home HD was evaluated under a complete care scenario with the inclusion of a health care aide remaining with the patient throughout the duration of treatment.

Outcomes

Annual per-patient maintenance and training costs related to assisted and self-care home HD and CCPD, presented in 2019 Canadian dollars.

Model, Perspective, & Time Frame

This model took the perspective of the Canadian public health payer using a 1-year time frame.

Results

Annual total per-patient maintenance (and training) costs by modality were the following: full-assist CCPD, $75.717 (initial training costs, $301); partial-assist CCPD, $67,765 ($4,385); full-assist home HD, $47,862 ($301); partial-assist home HD, $44,650 ($14,813); and full-assist home HD (complete care), $64,659 ($301).

Limitations

This model did not account for costs taken from the societal perspective or costs related to PD failure and modality switching. Additionally, this analysis reflects only costs experienced by a single center.

Conclusions

Assisted home-based dialysis modalities are viable treatment options for patients from a cost perspective. Future studies to consider graduation rates to full self-care from assisted dialysis and the cost implications of respite care are needed.

Percutaneous Versus Surgical Insertion of Peritoneal Dialysis Catheters: A Systematic Review and Meta-Analysis

Background:

Home-based peritoneal dialysis (PD) is an alternative to facility-based hemodialysis and has lower costs and greater freedom for patients with kidney failure. For a patient to undergo PD, a safe and reliable method of accessing the peritoneum is needed. However, different catheter insertion techniques may affect patient health outcomes.

Objective:

To compare the risk of infectious and mechanical complications between surgical (open and laparoscopic) PD catheter insertion and percutaneous catheter insertion.

Design:

Systematic review and meta-analysis.

Setting:

We searched for observational studies and randomized controlled trials (RCTs) in CENTRAL, EMBASE, MEDLINE, PubMed, and SCOPUS from inception until June 2018. Data were extracted by 2 independent reviewers based on a preformed template.

Patients:

Adult (aged 18+) patients with kidney failure who underwent a PD catheter insertion procedure.

Measurements:

We analyzed leak, malfunction, and bleed as early complications (occurring within 1 month of catheter insertion). Infectious complications (exit-site infections, tunnel infections, and peritonitis) were presented as both early complications and with the longest duration of follow-up.

Methods:

Random effects meta-analyses with the generic inverse variance method to estimate pooled rate ratios and 95% confidence intervals. We quantified heterogeneity by using the I2 statistic for inconsistency and assessed heterogeneity using the χ² test. Sensitivity analysis was performed by removing studies at high risk of bias as measured with the Newcastle-Ottawa Scale and the Cochrane Risk of Bias tool.

Results:

Twenty-four studies (22 observational, 2 RCTs) with 3108 patients and 3777 catheter insertions were selected. Data from 2 studies were unable to be extracted and were qualitatively assessed. In the remaining 22 studies, percutaneous insertion was associated with a lower risk of both exit-site infections (risk ratio [RR] = 0.36, 95% confidence interval [CI] = 0.24-0.53, I² = 0%) and peritonitis (RR = 0.52, 95% CI = 0.36-0.77, I² = 3%) within 1 month of the procedure. There was no difference in mechanical complication rates between the 2 techniques.

Limitations:

Lack of consistency in the time periods for the various outcomes reported, risk of bias concerns with respect to population comparability, and the inability to analyze individual component causes of primary nonfunction (catheter obstruction, catheter migration, and leak).

Conclusions:

Our meta-analysis suggests differences in early infectious complications in favor of percutaneous insertion and no significant differences in mechanical complications compared with surgical insertion. These findings have implications on the direction of PD programs in terms of maximizing operating room resources.

Metabolic Acidosis and Cardiovascular Disease in CKD

Rationale & Objective

Metabolic acidosis related to chronic kidney disease (CKD) is associated with an accelerated decline in glomerular filtration rate (GFR) and the development of end-stage kidney disease. Whether metabolic acidosis is associated with cardiovascular (CV) events in patients with CKD is unclear.

Study Design

Retrospective cohort study.

Setting & Participants

The Optum De-identified Electronic Health Records Dataset, 2007–2017, was used to generate a cohort of patients with non-dialysis-dependent CKD who had at least 3 estimated GFR < 60 mL/min/1.73 m². Patients with metabolic acidosis (serum bicarbonate 12 to <22 mEq/L) or normal serum bicarbonate (22‒29 mEq/L) at baseline were identified by 2 consecutive measurements 28‒365 days apart.

Predictor

Serum bicarbonate as a continuous variable.

Outcome

Primary outcome was a composite of major adverse cardiovascular events (MACE+). Secondary outcomes included individual components of the composite outcome.

Analytical Approach

Cox proportional hazards models to evaluate the association between 1-mEq/L increments in serum bicarbonate and MACE+.

Results

A total of 51,558 patients were evaluated, 34% had metabolic acidosis. The median follow-up period was 3.9–4.5 years, depending on the outcome assessed. The adjusted hazard ratio (HR) for MACE+ was 0.964 (95% CI, 0.961–0.968). For the individual components of incident heart failure (HF), stroke, myocardial infarction (MI), and CV death, HRs were 0.98 (95% CI, 0.97–0.98), 0.98 (95% CI, 0.97–0.99), 0.96 (95% CI, 0.96–0.97), and 0.94 (95% CI, 0.93–0.94), respectively, for every 1-mEq/L increase in serum bicarbonate.

Limitations

Possible residual confounding.

Conclusions

Metabolic acidosis in CKD is associated with an increased risk of MACE+ as well as the individual components of incident HF, stroke, MI, and CV death. Randomized controlled trials evaluating treatments for the correction of metabolic acidosis in CKD to prevent CV events are needed.

Impact of a screen, triage and treat program for identifying chronic disease risk in Indigenous children

BACKGROUND

The First Nations Community Based Screening to Improve Kidney Health and Prevent Dialysis project was a point-of-care screening program in rural and remote First Nations communities in Manitoba that aimed to identify and treat hypertension, diabetes and chronic kidney disease. The program identified chronic disease in 20% of children screened. We aimed to characterize clinical screening practices before and after intervention in children aged 10-17 years old and compare outcomes with those who did not receive the intervention.

METHODS

This observational, prospective cohort study started with community engagement and followed the principles of ownership, control, access and possession (OCAP). We linked participant data to administrative data at the Manitoba Centre for Health Policy to assess rates of primary care and nephrology visits, disease-modifying medication prescriptions and laboratory testing (i.e., glycosylated hemoglobin [HbA_1c], estimated glomerural filtration rate [eGFR] and urine albumin- or protein-to-creatinine ratio). We analyzed the differences in proportions in the 18 months before and after the intervention. We also conducted a 1:2 propensity score matching analysis to compare outcomes of children who were screened with those who were not.

RESULTS

We included 324 of 353 children from the screening program (43.8% male; median age 12.3 yr) in this study. After the intervention, laboratory testing increased by 5.8% (95% confidence interval [CI] 1.1% to 10.1%) for HbA_1c, by 9.9% (95% CI 4.2% to 15.5%) for eGFR and by 6.2% (95% CI 2.3% to 10.0%) for the urine albumin- or protein-to-creatinine ratio. We observed significant improvements in laboratory testing in screened patients in the group who were part of the program, compared with matched controls.

INTERPRETATION

Chronic disease surveillance and care increased significantly in children after the implementation of a point-of-care screening program in rural and remote First Nation communities. Interventions such as active surveillance programs have the potential to improve the chronic disease care being provided to First Nations children.

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.

Strategies to prevent hospital readmission and death in patients with chronic heart failure, chronic obstructive pulmonary disease, and chronic kidney disease: A systematic review and meta-analysis

BACKGROUND

Readmission following hospital discharge is common and is a major financial burden on healthcare systems.

OBJECTIVES

Our objectives were to 1) identify studies describing post-discharge interventions and their efficacy with respect to reducing risk of mortality and rate of hospital readmission; and 2) identify intervention characteristics associated with efficacy.

METHODS

A systematic review of the literature was performed. We searched MEDLINE, PubMed, Cochrane, EMBASE and CINAHL. Our selection criteria included randomized controlled trials comparing post-discharge interventions with usual care on rates of hospital readmission and mortality in high-risk chronic disease patient populations. We used random effects meta-analyses to estimate pooled risk ratios for all-cause and cause-specific mortality as well as all-cause and cause-specific hospitalization.

RESULTS

We included 31 randomized controlled trials encompassing 9654 patients (24 studies in CHF, 4 in COPD, 1 in both CHF and COPD, 1 in CKD and 1 in an undifferentiated population). Meta-analysis showed post-discharge interventions reduced cause-specific (RR = 0.71, 95% CI = 0.63-0.80) and all cause (RR = 0.90, 95% CI = 0.81-0.99) hospitalization, all-cause (RR = 0.73, 95% CI = 0.65-0.83) and cause-specific mortality (RR = 0.68, 95% CI = 0.54-0.84) in CHF studies, and all-cause hospitalization (RR = 0.52, 95% CI = 0.32-0.83) in COPD studies. The inclusion of a cardiac nurse in the multidisciplinary team was associated with greater efficacy in reducing all-cause mortality among patients discharged after heart failure admission (HR = 0.64, 95% CI = 0.54-0.75 vs. HR = 0.87, 95% CI = 0.73-1.03).

CONCLUSIONS

Post-discharge interventions reduced all-cause mortality, cause-specific mortality, and cause-specific hospitalization in CHF patients and all-cause hospitalization in COPD patients. The presence of a cardiac nurse was associated with greater efficacy in included studies. Additional research is needed on the impact of post-discharge intervention strategies in COPD and CKD patients.

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.

A Cost-Minimization Analysis of Nurse-Led Virtual Case Management in Late-Stage CKD

Introduction

Interventions are needed to improve early detection of indications for dialysis before development of severe symptoms or complications. This may reduce suboptimal dialysis starts, prevent hospitalizations, and decrease costs. Our objectives were to explore assumptions around a nurse-led virtual case management intervention for patients with late-stage chronic kidney disease (CKD) with a 2-year Kidney Failure Risk Equation (KFRE) estimated risk of kidney failure ≥80% and to estimate how these assumptions affect potential cost savings.

Methods

We performed a cost-minimization analysis by developing a decision analytic microsimulation model constructed from the perspective of the health payer. Our primary outcome was the break-even point, defined as the maximum amount a health payer could spend on the intervention without incurring any net financial loss or gain. The intervention group received remote telemonitoring, including daily measurement of several health metrics (blood pressure, oxygen saturation, and weight), and a validated symptom questionnaire accompanied by nurse-led case management, whereas the comparator group received usual care. We assumed patients received the intervention for a maximum of 2 years.

Results

The break-even point was $7339 per late-stage CKD patient enrolled in the intervention. Based on the distribution of time receiving the intervention, we determined a maximum monthly intervention cost of $703.37. In probabilistic sensitivity analyses, we found that 75% of simulations produced break-even points between $3929 and $9460.

Conclusion

Nurse-led virtual home monitoring interventions in patients with CKD at high risk of kidney failure have the potential for significant cost savings from the perspective of the health payer.

Validation of the Kidney Failure Risk Equation in Kidney Transplant Recipients

Background:

Predicting allograft failure in kidney transplant recipients can help plan renal replacement therapy and guide patient-provider communication. The kidney failure risk equation (KFRE) accurately predicts the need for dialysis in patients with chronic kidney disease (CKD), but has not been validated in kidney transplant recipients.

Objective:

We sought to validate the 4-variable KFRE (age, sex, estimated glomerular filtration rate [eGFR], and urine albumin-to-creatinine ratio [ACR]) for prediction of 2- and 5-year death-censored allograft failure.

Design:

Retrospective cohort study.

Setting:

Four independent North American Cohorts from Ontario, Canada; Alberta, Canada; Manitoba, Canada; and Wisconsin, United States, between January 1999 and December 2017.

Patients:

Adult kidney transplant patients at 1-year posttransplantation.

Measurements:

Kidney failure risk as measured by the KFRE (eGFR, urine ACR, age, and sex).

Methods:

We included all adult patients who had at least 1 serum creatinine and at least 1 urine ACR measurement approximately 1 year following kidney transplantation. The performance of the KFRE was evaluated using the area under the receiver operating characteristic curve (C-statistic). C-statistics from the 4 cohorts were meta-analyzed using random-effects models.

Results:

A total of 3659 patients were included. Pooled C-statistics were good in the entire population, at 0.81 (95% confidence interval: 0.72-0.91) for the 2-year KFRE and 0.73 (0.67-0.80) for the 5-year KFRE. Discrimination improved among patients with poorer kidney function (eGFR < 45 mL/min/1.73 m²), with a C-statistic of 0.88 (0.78-0.98) for the 2-year KFRE and 0.83 (0.74-0.91) for the 5-year KFRE.

Limitations:

The KFRE does not predict episodes of acute rejection and there was heterogeneity between cohorts.

Conclusions:

The KFRE accurately predicts kidney failure in kidney transplant recipients at 1-year posttransplantation. Further validation in larger cohorts with longer follow-up times can strengthen the case for clinical implementation.

Peripheral Artery Disease: Its Adverse Consequences With and Without CKD

RATIONALE & OBJECTIVES

Chronic kidney disease (CKD) is a potent risk factor for macrovascular disease and death. Peripheral artery disease (PAD) is more common in patients with CKD and is associated with lower-limb complications and mortality. We sought to compare the prevalence of PAD in and outside the setting of kidney disease and examine how PAD affects the risk for adverse health outcomes, specifically lower-limb complications, cardiovascular events, and survival.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

453,573 adult residents of Manitoba with at least 1 serum creatinine measurement between 2007 and 2014.

EXPOSURE

PAD defined by hospital discharge diagnosis codes and medical claims.

OUTCOMES

All-cause mortality, cardiovascular events, and lower-limb complications, including foot ulcers and nontraumatic amputations.

ANALYTICAL APPROACH

Survival analysis using Cox proportional hazards models.

RESULTS

The prevalence of PAD in our study population was 4.5%, and patients with PAD were older, were more likely to be male, and had a higher burden of comorbid conditions, including diabetes and CKD. PAD was associated with higher risks for all-cause mortality, cardiovascular events, and lower-limb complications in patients with estimated glomerular filtration rate (eGFR) ≥ 60mL/min/1.73m², those with CKD GFR categories 3 to 5 (G3-G5), and those treated by dialysis (CKD G5D). Although HRs for PAD were lower in the CKD population, event rates were higher as compared with those with eGFR≥60mL/min/1.73m². In particular, compared with patients with eGFR≥60mL/min/1.73m² and without PAD, patients with CKD G5D had 10- and 12-fold higher risks for lower-limb complications, respectively (adjusted HRs of 10.36 [95% CI, 8.83-12.16] and 12.02 [95% CI, 9.58-15.08] for those without and with PAD, respectively), and an event rate of 75/1,000 patient-years.

LIMITATIONS

Potential undercounting of PAD and complications using administrative codes and the limited ability to examine quality-of-care indicators for PAD.

CONCLUSIONS

PAD is more common in patients with CKD G3-G5 and G5D compared with those with eGFR≥60mL/min/1.73m² and frequently leads to lower-limb complications. Medical interventions and care pathways specifically designed to slow or prevent the development of lower-limb complications in this population are urgently needed.

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.

Integrating Risk-Based Care for Patients With Chronic Kidney Disease in the Community: Study Protocol for a Cluster Randomized Trial

Background:

A risk-based model of care for managing patients with chronic kidney disease (CKD) using the Kidney Failure Risk Equation (KFRE) has been successfully integrated into nephrology care pathways in several jurisdictions. However, as most patients with CKD can be managed in primary care, the next pertinent steps would be to integrate the KFRE into primary care pathways.

Objective:

Using a risk-based approach for guiding CKD care in the primary care setting, the objective of the study is to develop, implement, and evaluate tools that can be used by patients and providers.

Design:

This study is a multicenter cluster randomized control trial.

Setting:

Thirty-two primary care clinics belonging to the Canadian Primary Care Sentinel Surveillance Network (CPCSSN) across Manitoba and Alberta.

Patients:

All patients at least 18 years old or older with CKD categories G3-G5 attending the participating clinics; we estimate each clinic will have an average of 185 patients with CKD.

Methods:

Thirty-two primary care clinics will be randomized to receive either an active knowledge translation intervention or no intervention. The intervention involves the addition of the KFRE and decision aids to clinics’ Data Presentation Tool (DPT), as well as patient-facing visual aids, a medical detailing visit, and sentinel feedback reports. Control clinics will only be exposed to current guidelines for CKD management, without active dissemination.

Measurements:

Data from the CPCSSN repository will be used to assess whether a risk-based care approach affected management of CKD. Primary outcomes are as follows: the proportion of patients with measured urine albumin-to-creatinine ratio, and the proportion of patients being appropriately treated with angiotensin-converting enzyme inhibitor or angiotensin receptor blockers. Secondary outcomes are as follows: the optimal management of diabetes (hemoglobin A1C <8.5%, and the use of sodium-glucose cotransporter-2 inhibitors in CKD G3 patients), hypertension (office blood pressure <130/80 for patients with diabetes, 140/90 for those without), and cardiovascular risk (statin prescription); prescriptions of nonsteroidal anti-inflammatory drugs; and decline in estimated glomerular filtration rate (eGFR). In addition, in a substudy, we will measure CKD-specific health literacy and trust in physician care via surveys administered in the clinic post-visit. At the provider level, we will measure satisfaction with the risk prediction tools. Lastly, at the health system level, outcomes include cost of CKD care, and appropriate referrals for patients at high risk of kidney failure based on provincial guidelines. Primary and secondary outcomes will be measured at the patient level and enumerated at the clinic level 1 year after the intervention implementation, except for decline in eGFR, which will be measured 2 years postintervention.

Limitations:

Limitations include scalability of the proposal in other health care systems.

Conclusions:

If successful, this intervention has the potential to improve the management of patients with CKD within Canadian primary care settings, leading to health and economic benefits, and influencing practice guidelines.

Trial Registration:

ClinicalTrials.gov identifier: NCT03365063

Cost of Dialysis Therapy by Modality in Manitoba

BACKGROUND AND OBJECTIVES

The prevalence of ESKD is increasing worldwide. Treating ESKD is disproportionately costly in comparison with its prevalence, mostly due to the direct cost of dialysis therapy. Here, we aim to provide a contemporary cost description of dialysis modalities, including facility-based hemodialysis, peritoneal dialysis, and home hemodialysis, provided with conventional dialysis machines and the NxStage System One.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We constructed a cost-minimization model from the perspective of the Canadian single-payer health care system including all costs related to dialysis care. The labor component of costs consisted of a breakdown of activity-based per patient direct labor requirements. Other costs were taken from statements of operations for the kidney program at Seven Oaks General Hospital (Winnipeg, Canada). All costs are reported in Canadian dollars.

RESULTS

Annual maintenance expenses were estimated as $64,214 for in-center facility hemodialysis, $43,816 for home hemodialysis with the NxStage System One, $39,236 for home hemodialysis with conventional dialysis machines, and $38,658 for peritoneal dialysis. Training costs for in-center facility hemodialysis, home hemodialysis with the NxStage System One, home hemodialysis with conventional dialysis machines, and peritoneal dialysis are estimated as $0, $16,143, $24,379, and $7157, respectively. The threshold point to achieve cost neutrality was determined to be 9.7 months from in-center hemodialysis to home hemodialysis with the NxStage System One, 12.6 months from in-center hemodialysis to home hemodialysis with conventional dialysis machines, and 3.2 months from in-center hemodialysis to peritoneal dialysis.

CONCLUSIONS

Home modalities have lower maintenance costs, and beyond a short time horizon, they are most cost efficient when considering their incremental training expenses.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2018_07_18_CJASNPodcast_18_8_F.mp3.

Screening for kidney disease in Indigenous Canadian children: The FINISHED screen, triage and treat program

Background

Indigenous populations are disproportionately affected by kidney failure at younger ages than other ethnic groups in Canada. As symptoms do not occur until disease is advanced, early kidney disease risk is often unrecognized.

Objectives

We sought to evaluate the yield of community-based screening for early risk factors for kidney disease in youth from rural Indigenous communities in Canada.

Methods

The FINISHED project screened 11 rural First Nations communities in Manitoba, Canada after community and school engagement. The results for the 10- to 17-year olds are reported here. Body mass index (BMI), blood pressure, estimated glomerular filtration rate (eGFR), hemoglobin A1c's (HbA1c) and urine albumin-to-creatinine ratios (ACR) were assessed. All children were triaged and referred to either primary or tertiary care, depending on risk.

Results

A total of 353 were screened (estimated 22.4% of population). The median age was 12 years (IQR 10 to 13), 55% were female and 55% were overweight or obese. Overall, 21.8% of children had at least one abnormality. Hypertension was identified in 5.4% and 11.9% had prehypertension. None of the children had an eGFR < 60 ml/min/1.73 m² however 10.5% had an ACR > 3 mg/mmol and 6.2% had an eGFR < 90 ml/min/1.73 m² suggestive of early kidney disease. Diabetes was identified in 1.4%, and 1.4% had HbA1c's between 6.1% and 6.49%.

Conclusions

Risk factors for chronic kidney disease are highly prevalent in rural Indigenous children. More research is required to confirm the persistence of these findings, and to evaluate the efficacy of screening children to prevent or delay progression to kidney failure.

Long term health outcomes in patients with a history of myocardial infarction: A population based cohort study

Background

Myocardial infarction (MI) is associated with high morbidity and mortality, particularly in the first 12 months post-event. Interventions such as dual antiplatelet therapy can reduce the risk of major adverse cardiovascular events (MACE), but the duration of the high-risk time interval and the optimal prescription time frame for these interventions remains unknown.

Design, setting, participants, and measurements

We performed a retrospective cohort study using data from medical services and hospitalizations in Manitoba, Canada for patients admitted with a MI between April 2006 and March 2010, and followed until Nov 30, 2014. We used survival analysis to determine the cumulative incidence of death, subsequent MI, or stroke, and used Cox proportional hazards models to assess factors associated with these endpoints.

Results

There were 8,493 patients in Manitoba admitted to hospital for a MI during the study period. Of those, 6,749 (79.5%) survived for at least 1 year without a recurrent MI or stroke. In the following year, this population remained at high risk, with 372 (5.5%) of the remaining patients dying in the next twelve months (48.1% cardiovascular deaths), 244 (3.6%) having a recurrent MI, and 74 (1.1%) having a stroke. Older age, male sex, diabetes, prior stroke, prior heart failure, prior unstable angina, and absence of revascularization were associated with worse long-term prognosis.

Conclusions

The risk of MACE remains elevated among post-MI patients after the first year. Interventions to more intensively monitor, evaluate, and treat these patients should be considered beyond the first year following myocardial infarction.

Dipeptidyl Peptidase-4 Inhibitors in Chronic Kidney Disease: A Systematic Review of Randomized Clinical Trials

BACKGROUND

Chronic kidney disease (CKD) is common in patients with type 2 diabetes mellitus (T2DM) and limits therapeutic options. Dipeptidyl peptidase-4 (DPP-4) inhibitors represent a novel class of oral glucose-lowering agents and are known to be safe and effective in the general population.

METHODS

We searched Cochrane, EMBASE, and PubMed from the time of their inception until March 2015. We included randomized controlled trials analyzing the efficacy (change in hemoglobin A1C [HbA1C]) and safety of DPP-4 agents in individuals with reduced kidney function (estimated glomerular filtration rate <60 mL/min/1.73 m2). We extracted study characteristics, participants' baseline characteristics, and safety outcomes from eligible studies. We performed a random effects meta-analysis to summarize the change in HbA1C and the relative risk of cardiovascular events in patients with T2DM and CKD. We also collected data on hypoglycemia, other serious adverse events, and mortality.

RESULTS

We reviewed 12 studies with 4,403 patients with CKD and 239 on dialysis, finding a mean weighted decline in HbA1C of -0.48 (95% CI -0.61 to -0.35) with DPP-4 inhibitor therapy compared to placebo. DPP-4 inhibitors did not result in any additional adverse events, hypoglycemic episodes, or increased mortality. Restricting to studies with low risk of bias did not alter these findings.

CONCLUSIONS

DPP-4 inhibitors can lower HbA1C without increasing the risk of cardiovascular or other major adverse events in patients with CKD. Few studies reported critical adverse events such as heart failure and hypersensitivity. If compared with other oral antiglycemic drugs, the effect of DPP-4 inhibitors is limited; however, their low risk of hypoglycemia may favor their use in patients with CKD.

SUMMARY

This systematic review of DPP-4 inhibitors in CKD suggests that they reduce HbA1C by about 0.5%. Furthermore, there was not any increase in the risk for significant adverse events. More research is needed to determine the safety and efficacy of DPP-4 inhibitors in CKD.

Identifying Potential Biases in the Nephrology Literature

Observational studies are common in the nephrology literature, particularly given the lack of large randomized trials. While these studies have identified important associations, potential biases, if unrecognized, can result in misinterpreted conclusions. In this review, we present an example of four potentially important biases (lead time bias, survivor bias, immortal time bias, and index event bias) that can result in inaccurate estimates of association between risk factors or treatments and outcomes. Recognition of these potential biases can help improve study design and interpretation.

Early mortality on continuous renal replacement therapy (CRRT): the prairie CRRT study

Background

Patients with acute kidney injury (AKI) requiring renal replacement therapy (RRT) have an increased short-term and long-term risk of mortality. In most North American intensive care units (ICUs), these patients receive continuous renal replacement therapy (CRRT).

Objective

We aim to identify clinical and demographic factors associated with mortality within 24 h of initiating CRRT.

Design

This paper is a prospective cohort study.

Setting

The setting involves three ICUs (12-bed surgical ICU, 10-bed medical ICU, and a 7-bed combined ICU for both medical and surgical patients) of the Regina Qu’Appelle Health Region (RQHR) Saskatchewan, Canada.

Patients

The patients were 106 individuals with AKI who were admitted to the ICUs and received CRRT from April 2013 to September 2014.

Measurements

Date and time of admission, transfer to, and initiation of CRRT were documented. Demographic data, use of vasoactive medications, ventilator settings, pH, urine output, and chronic disease comorbidities were measured.

Methods

The methods involved a stepwise multiple variable logistic regression model using death within 24 h of starting CRRT as the dependent variable, with significant variables derived from univariate analysis as covariates.

Results

Of the 2634 patients admitted to the ICUs in the study period (April 2013 to September 2014), 83.6 % (2201/2634) had no AKI. Two hundred and sixty-nine or 10.2 % of the patients had stage 3 AKI. One hundred six of the 269 patients (40%) were started on CRRT. Of those on CRRT, 66/106 died in the ICU while on CRRT. Seventeen of the 66 patients (26%) died within 24 h of initiating therapy. In univariate logistic regression models, factors associated with early mortality included fraction of inspired oxygen (per 0.1 unit) (OR 1.39, 95 % CI 1.09–1.77); epinephrine dose >10 μg/min (OR 5.81, 95 % CI 1.86–18.16); vasopressin >0.02 μg/min (OR 3.99, 95 % CI 1.07–14.84); and norepinephrine dose >20 μg/min (OR 11.04, 95 % CI 2.38–51.24) which were associated with early mortality. When included in stepwise multivariate logistic regression analysis, only FiO₂ (per 0.1 unit) and the dose of norepinephrine of >20 μg/min were independently associated with early mortality.

Limitations

The small sample size was a limitation of this study.

Conclusion

Patients admitted to the ICU with AKI requiring CRRT have a high risk of early mortality. In these patients, vasopressor use and hypoxia were independently associated with adverse short-term survival.

A retrospective review of the two-step tuberculin skin test in dialysis patients

BACKGROUND

Reactivation of latent Mycobacterium tuberculosis infection (LTBI) is a health concern for patients on dialysis or receiving a kidney transplant, as these patients are often immunosuppressed. The most frequently used test for LTBI screening in this population is the tuberculin skin test (TST). The diagnostic accuracy (sensitivity and specificity) of the TST in a contemporary North American or Western European dialysis population is unknown.

OBJECTIVES

Our objective was to determine the diagnostic accuracy and clinical utility of the two-step TST in patients receiving dialysis.

DESIGN

This is a retrospective cohort study.

SETTING

This study is set at four tertiary dialysis units across Winnipeg, Manitoba.

PATIENTS

There are 483 chronic hemodialysis and peritoneal dialysis patients in the study.

MEASUREMENTS

The measurements are sensitivity and specificity of the TST with respect to abnormal chest X-ray.

METHODS

All patients received a two-step TST and assessment of risk factors for prior tuberculosis (TB) infection between February 2008 and December 2008. This cohort was retrospectively linked to our tuberculosis registry to ascertain if prophylaxis was received for LTBI.

RESULTS

At an induration cutoff of 5 mm, 62 (13 %) patients had a positive two-step TST. Patients with a known Bacillus Calmette-Guérin (BCG) vaccination were more likely to test positive (50 % of those with a positive TST had a BCG versus 34 % with a negative TST, p = 0.05). Using a diagnostic gold standard of an abnormal chest X-ray as a proxy for LTBI, the sensitivity of the TST was only 14 % and the specificity was 88 %. Only 8 of 62 patients with a positive TST (13 %) received prophylaxis for LTBI. None of the patients who tested negative were treated.

LIMITATIONS

There is a lack of a truly accurate gold standard for LTBI.

CONCLUSIONS

The TST has limited diagnostic and clinical utility for LTBI screening in patients on dialysis. Further research into the diagnostic accuracy of interferon-gamma release assays and a revision of LTBI screening guidelines in patients on dialysis should be considered.

The Prevalence of CKD in Rural Canadian Indigenous Peoples: Results From the First Nations Community Based Screening to Improve Kidney Health and Prevent Dialysis (FINISHED) Screen, Triage, and Treat Program

BACKGROUND

Indigenous Canadians have high rates of risk factors for chronic kidney disease (CKD), in particular diabetes. Furthermore, they have increased rates of complications associated with CKD, such as kidney failure and vascular disease. Our objective was to describe the prevalence of CKD in this population.

STUDY DESIGN

Cross-sectional cohort.

SETTING & PARTICIPANTS

Indigenous (First Nations) Canadians 18 years or older screened as part of the First Nations Community Based Screening to Improve Kidney Health and Prevent Dialysis (FINISHED) project, an initiative completed in 2015 that accomplished community-wide screening in 11 rural communities in Manitoba, Canada.

PREDICTORS

Indigenous ethnicity and geographic location (communities accessible by road compared with those accessible only by air).

OUTCOME

Prevalence of CKD, presumed based on a single ascertainment of urine albumin-creatinine ratio (UACR) ≥ 30mg/g and/or estimated glomerular filtration rate (eGFR)<60mL/min/1.73m(2).

MEASUREMENTS

Kidney function measured by eGFR (CKD-EPI creatinine equation) and UACR.

RESULTS

1,346 adults were screened; 25.5% had CKD, defined as UACR≥30mg/g or eGFR<60mL/min/1.73m(2). Communities accessible by road had a lower prevalence of CKD (17.6%) than more remote communities accessible only by air (34.4%). Of those screened, 3.3% had reduced kidney function (defined as eGFR<60mL/min/1.73m(2)). Severely increased albuminuria was present in 5.0% of those screened.

LIMITATIONS

Presumption of chronicity based on a single ascertainment. There is a possibility of sampling bias, the net direction of which is uncertain.

CONCLUSIONS

We found a 2-fold higher prevalence of CKD in indigenous Canadians in comparison to the general population and a prevalence of severely increased albuminuria that was 5-fold higher. This is comparable to patients with diabetes and/or hypertension. Public health strategies to screen, triage, and treat all Canadian indigenous peoples with CKD should be considered.

An Economic Assessment Model of Rural and Remote Satellite Hemodialysis Units

BACKGROUND

Kidney Failure is epidemic in many remote communities in Canada. In-centre hemodialysis is provided within these settings in satellite hemodialysis units. The key cost drivers of this program have not been fully described. Such information is important in informing the design of programs aimed at optimizing efficiency in providing dialysis and preventative chronic kidney disease care in remote communities.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

We constructed a cost model based on data derived from 16 of Manitoba, Canada's remote satellite units. We included all costs for operation of the unit, transportation, treatment, and capital costs. All costs were presented in 2013 Canadian dollars.

RESULTS

The annual per-patient cost of providing hemodialysis in the satellite units ranged from $80,372 to $215,918 per patient, per year. The median per patient, per year cost was $99,888 (IQR $89,057-$122,640). Primary cost drivers were capital costs related to construction, human resource expenses, and expenses for return to tertiary care centres for health care. Costs related to transport considerably increased estimates in units that required plane or helicopter transfers.

CONCLUSIONS

Satellite hemodialysis units in remote areas are more expensive on a per-patient basis than hospital hemodialysis and satellite hemodialysis available in urban areas. In some rural, remote locations, better value for money may reside in local surveillance and prevention programs in addition support for home dialysis therapies over construction of new satellite hemodialysis units.

Cost-effectiveness of primary screening for CKD: a systematic review

BACKGROUND

Chronic kidney disease (CKD) is a major health problem with an increasing incidence worldwide. Data on the cost-effectiveness of CKD screening in the general population have been conflicting.

STUDY DESIGN

Systematic review.

SETTING & POPULATION

General, hypertensive, and diabetic populations. No restriction on setting.

SELECTION CRITERIA FOR STUDIES

Studies that evaluated the cost-effectiveness of screening for CKD.

INTERVENTION

Screening for CKD by proteinuria or estimated glomerular filtration rate (eGFR).

OUTCOMES

Incremental cost-effectiveness ratio of screening by proteinuria or eGFR compared with either no screening or usual care.

RESULTS

9 studies met criteria for inclusion. 8 studies evaluated the cost-effectiveness of proteinuria screening and 2 evaluated screening with eGFR. For proteinuria screening, incremental cost-effectiveness ratios ranged from $14,063-$160,018/quality-adjusted life-year (QALY) in the general population, $5,298-$54,943/QALY in the diabetic population, and $23,028-$73,939/QALY in the hypertensive population. For eGFR screening, one study reported a cost of $23,680/QALY in the diabetic population and the range across the 2 studies was $100,253-$109,912/QALY in the general population. The incidence of CKD, rate of progression, and effectiveness of drug therapy were major drivers of cost-effectiveness.

LIMITATIONS

Few studies evaluated screening by eGFR. Performance of a quantitative meta-analysis on influential assumptions was not conducted because of few available studies and heterogeneity in model designs.

CONCLUSIONS

Screening for CKD is suggested to be cost-effective in patients with diabetes and hypertension. CKD screening may be cost-effective in populations with higher incidences of CKD, rapid rates of progression, and more effective drug therapy.

Bacterial endocarditis. Survey of patients treated between 1963 and 1975

Hospital records of forty-nine patients with a diagnosis of bacterial endocarditis at the University of Kentucky Medical Center Hospital from 1963 to 1975 were reviewed. Data collected and statistically analyzed resulted in the following conclusions: 1. Bacterial endocarditis affected males three to four times as often as females. 2. Morbidity was significant, with an average hospital stay of 4 weeks. 3. The mortality rate among the entire group of patients was 42.8 per cent. A significantly higher rate of 66.7 per cent was noted in patients with prosthetic heart valves. 4. The most prevalent predisposing factor was rheumatic heart disease. 5. There were five cases (10.2 per cent) in which dental procedures were the probable precipitating cause, once again pointing out the importance of detecting susceptible patients and proceeding with dental therapy only after adequate prophylactic measures. 6. The most frequently isolated microorganism was Staphylococcus aureus. 7. Chloramphenicol was the most effective in vitro antiboitic tested, with erythromycin a close second. Although it might appear that penicillin was not as effective, the concentration in actual usage may differ significantly from that in the tested discs. Penicillin, therefore, still remains the foundation for treatment in susceptible cases.