Public and patient perspectives on the use of clinical and administrative health data to identify and contact people at risk of future illness-The case of chronic kidney disease

For decades, researchers have used linkable administrative health data for evaluating the health care system, subject to local privacy legislation. In Ontario, Canada, the relevant privacy legislation permits some organizations (prescribed entities) to conduct this kind of research but is silent on their ability to identify and contact individuals in those datasets. Following consultation with the Office of the Information and Privacy Commissioner of Ontario, we developed a pilot study to identify and contact by mail a sample of people at high risk for kidney failure within the next 2 years, based on laboratory and administrative data from provincial datasets held by ICES, to ensure they receive needed kidney care. Before proceeding, we conducted six focus groups to understand the acceptability to the public and people living with chronic kidney disease of direct mail outreach to people at high risk of developing kidney failure. While virtually all participants indicated they would likely participate in the study, most felt strongly that the message should come directly from their primary care provider or whoever ordered the laboratory tests, rather than from an unknown organization. If this is not possible, they felt the health care provider should be made aware of the concern related to their kidney health. Most agreed that, if health authorities could identify people at high risk of a treatable life-threatening illness if caught early enough, there is a social responsibility to notify people. While privacy laws allow for free flow of health information among health care providers who provide direct clinical care, the proposed case-finding and outreach falls outside that model. Enabling this kind of information flow will require greater clarity in existing laws or revisions to these laws. This also requires adequate notification and culture change for health care providers and the public around information uses and flows.

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 addictions services are utilized by those with CKD is unknown. We examined the history of mental health and addictions 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 addictions service use within the previous 3 years across levels of kidney function (eGFR$\ \ge $60, 45 to < 60, 30 to < 45, 15 to < 30, <15 mL/min per 1.73m2 and maintenance dialysis). We calculated prevalence ratios (PR) 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 scores.

RESULTS

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

CONCLUSIONS

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

Patient Care Gaps Prior to Maintenance Dialysis Initiation: A Population-Based Retrospective Study

Background

Guidelines in Ontario, Canada, recommend timely referral for multidisciplinary kidney care to facilitate planned dialysis initiation. Many patients do not receive recommended multidisciplinary kidney care prior to dialysis.

Objective

To better understand why this gap in pre-dialysis care exists, we conducted a study to describe the pathways by which patients initiate maintenance dialysis.

Design

A retrospective cohort study.

Setting

Population-based, using health care administrative databases from Ontario, Canada.

Patients

Adults initiating maintenance dialysis from April 2016 to March 2019.

Measurements and methods

Patients were grouped based on whether they received recommended multidisciplinary kidney care prior to dialysis initiation (at least 1 year of care with at least 2 visits). For those who did not receive recommended care, we grouped patients as having no identified care gap or into the following groups: (1) lack of timely chronic kidney disease (CKD) screening, (2) late nephrology referral (<1 year), or (3) late or no referral for multidisciplinary kidney care among patients followed by a nephrologist for at least 1 year.

Results

A total of 9216 patients were included with a mean (standard deviation) age of 66 (15) years, and 61.5% were male. Of the total, 896 (9.7%) patients died, 7671 (83.2%) remained on dialysis at 90 days, and 649 (7.0%) had stopped dialysis due to kidney function recovery within 90 days. Of the 9216 patients, 5434 (59%) had not received recommended multidisciplinary kidney care. Among those without recommended care, there were 2251 (41.4%) patients with no identified care gaps, 1351 (24.9%) patients with a lack of timely CKD screening, 359 (6.6%) patients with late nephrology referral, and 1473 (27.1%) patients with late or no referral for multidisciplinary kidney care.

Limitations

We could not determine if patients were referred but declined multidisciplinary kidney care.

Conclusions

More than half of patients had not received recommended multidisciplinary kidney care. Many patients experienced an acute decline in kidney function, which may not be preventable, but in others, there were missed opportunities for CKD screening or early referral to nephrology, or at the level of nephrology practice for early referral for multidisciplinary care. This work could be used to inform policies aimed at improving increased uptake of multidisciplinary kidney care prior to dialysis.

Hypocalcemia Risk of Denosumab Across the Spectrum of Kidney Disease: A Population-Based Cohort Study

Denosumab can be used in patients with chronic kidney disease (CKD) but has been linked with cases of severe hypocalcemia. The incidence of and risk factors for hypocalcemia after denosumab use are not well established. Using linked health care databases at ICES, we conducted a population-based cohort study of adults >65 years old with a new prescription for denosumab or a bisphosphonate between 2012 and 2020. We assessed incidence of hypocalcemia within 180 days of drug dispensing and stratified results by estimated glomerular filtration rate (eGFR in mL/min/1.73 m² ). We used Cox proportional hazards to assess risk factors for hypocalcemia. There were 59,151 and 56,847 new denosumab and oral bisphosphonate users, respectively. Of the denosumab users, 29% had serum calcium measured in the year before their prescription, and one-third had their serum calcium checked within 180 days after their prescription. Mild hypocalcemia (albumin corrected calcium <2.00 mmol/L) occurred in 0.6% (95% confidence interval [CI] 0.6, 0.7) of new denosumab users and severe hypocalcemia (<1.8 mmol/L) in 0.2% (95% CI 0.2, 0.3). In those with an eGFR <15 or receiving maintenance dialysis, the incidence of mild and severe hypocalcemia was 24.1% (95% CI 18.1, 30.7) and 14.9% (95% CI 10.1, 20.7), respectively. In this group, kidney function and baseline serum calcium were strong predictors of hypocalcemia. We did not have information on over-the-counter vitamin D or calcium supplementation. In new bisphosphonate users, the incidence of mild hypocalcemia was 0.3% (95% CI 0.3, 0.3) with an incidence of 4.7% (95% CI 1.5, 10.8) in those with an eGFR <15 or receiving maintenance dialysis. In this large population-based cohort, we found that the overall risk of hypocalcemia with new denosumab use was low but increased substantially in those with eGFR <15 mL/min/1.73 m² . Future studies should investigate strategies to mitigate hypocalcemia. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Perceptions of Artificial Intelligence Use in Primary Care: A Qualitative Study with Providers and Staff of Ontario Community Health Centres

PURPOSE

To understand staff and health care providers' views on potential use of artificial intelligence (AI)-driven tools to help care for patients within a primary care setting.

METHODS

We conducted a qualitative descriptive study using individual semistructured interviews. As part of province-wide Learning Health Organization, Community Health Centres (CHCs) are a community-governed, team-based delivery model providing primary care for people who experience marginalization in Ontario, Canada. CHC health care providers and staff were invited to participate. Interviews were audio-recorded and transcribed verbatim. We performed a thematic analysis using a team approach.

RESULTS

We interviewed 27 participants across 6 CHCs. Participants lacked in-depth knowledge about AI. Trust was essential to acceptance of AI; people need to be receptive to using AI and feel confident that the information is accurate. We identified internal influences of AI acceptance, including ease of use and complementing clinical judgment rather than replacing it. External influences included privacy, liability, and financial considerations. Participants felt AI could improve patient care and help prevent burnout for providers; however, there were concerns about the impact on the patient-provider relationship.

CONCLUSIONS

The information gained in this study can be used for future research, development, and integration of AI technology.

Long-term Health Care Utilization and Associated Costs After Dialysis-Treated Acute Kidney Injury in Children

RATIONALE & OBJECTIVE

Acute kidney injury (AKI) is common among hospitalized children and is associated with increased hospital length of stay and costs. However, there are limited data on postdischarge health care utilization after AKI hospitalization. Our objectives were to evaluate health care utilization and physician follow-up patterns after dialysis-treated AKI in a pediatric population.

STUDY DESIGN

Retrospective cohort study, using provincial health administrative databases.

SETTING & PARTICIPANTS

All children (0-18 years) hospitalized between 1996 and 2017 in Ontario, Canada. Excluded individuals comprised non-Ontario residents; those with metabolic disorders or poisoning; and those who received dialysis or kidney transplant before admission, a kidney transplant by 104 days after discharge, or were receiving dialysis 76-104 days from dialysis start date.

EXPOSURE

Episodes of dialysis-treated AKI, identified using validated health administrative codes. AKI survivors were matched to 4 hospitalized controls without dialysis-treated AKI by age, sex, and admission year.

OUTCOME

Our primary outcome was postdischarge hospitalizations, emergency department visits, and outpatient physician visits. Secondary outcomes included outpatient visits by physician type and composite health care costs.

ANALYTICAL APPROACH

Proportions with≥1 event and rates (per 1,000 person-years). Total and median composite health care costs. Adjusted rate ratios using negative binomial regression models.

RESULTS

We included 1,688 pediatric dialysis-treated AKI survivors and 6,752 matched controls. Dialysis-treated AKI survivors had higher rehospitalization and emergency department visit rates during the analyzed follow-up periods (0-1, 0-5, and 0-10 years postdischarge, and throughout follow-up), and higher outpatient visit rates in the 0-1-year follow-up period. The overall adjusted rate ratio for rehospitalization was 1.46 (95% CI, 1.25-1.69; P<0.0001) and for outpatient visits was 1.16 (95% CI, 1.09-1.23; P=0.01). Dialysis-treated AKI survivors also had higher health care costs. Nephrologist follow-up was infrequent among dialysis-treated AKI survivors (18.6% by 1 year postdischarge).

LIMITATIONS

Potential miscoding of study exposures or outcomes. Residual uncontrolled confounding. Data for health care costs and emergency department visits was unavailable before 2006 and 2001, respectively.

CONCLUSIONS

Dialysis-treated AKI survivors had greater postdischarge health care utilization and costs versus hospitalized controls. Strategies are needed to improve follow-up care for children after dialysis-treated AKI to prevent long-term complications.

The Alliance for Healthier Communities as a Learning Health System for primary care: A qualitative analysis in Ontario, Canada

RATIONALE, AIMS AND OBJECTIVES

A learning health system model can be used to efficiently evaluate and incorporate evidence-based care into practice. However, there is a paucity of evidence describing key organizational attributes needed to ensure a successful learning health system within primary care. We interviewed stakeholders for a primary care learning health system in Ontario, Canada (the Alliance for Healthier Communities) to identify strengths and areas for improvement.

METHOD

We conducted a qualitative descriptive study using individual semistructured interviews with Alliance stakeholders between December 2019 and March 2020. The Alliance delivers community-governed primary healthcare through 109 organizations including Community Health Centres (CHCs). All CHC staff within the Alliance were invited to participate. Interviews were audio-recorded and transcribed verbatim. We performed a thematic analysis using a team approach.

RESULTS

We interviewed 29 participants across six CHCs, including Executive Directors, managers, healthcare providers and data support staff. We observed three foundational elements necessary for a successful learning health system within primary care: shared organizational goals and culture, data quality and resources. Building on this foundation, people are needed to drive the learning health system, and this is conditional on their level of engagement. The main factors motivating staff member's engagement with the learning health system included their drive to help improve patient care, focusing on initiatives of personal interest and understanding the purpose of different initiatives. Areas for improvement were identified such as the ability to extract and use data to inform changes in real-time, better engagement and protected time for providers to do improvement work, and more staff dedicated to data extraction and analysis.

CONCLUSIONS

We identified key components needed to establish a learning health system in primary care. Similar primary care organizations in Canada and elsewhere can use these insights to guide their development as learning health systems.

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.

The Alliance for Healthier Communities' journey to a learning health system in primary care

Introduction

The Alliance for Healthier Communities represents community-governed healthcare organizations in Ontario, Canada including Community Health Centres, which provide primary care to more disadvantaged populations.

Methods

In this experience report, we describe the Alliance's journey towards becoming a learning health system using examples for organizational culture, data and analytics, people and partnerships, client engagement, ethics and oversight, evaluation and dissemination, resources, identification and prioritization, and deliverables and impact.

Results

Many of the foundational elements for a learning health system were already in place at the Alliance including an integrated and accessible data platform. Leadership championed and embraced the movement towards a learning health system, which led to restructuring of the organization. This included role changes for data support personnel, better communication, and dissemination plans, strategies to engage clinicians and other front-line staff, restructuring of committees for more collaborative planning and prioritization of quality improvement and research initiatives, and the development of a new Practice-Based Learning Network for more opportunities to use the data for research and evaluation.

Conclusions

Next steps will focus on continued clinical engagement and partnerships as well as ongoing reflection on the transition and success of the learning health system work.

Printed educational materials directed at Ontario family physicians do not improve adherence to guideline recommendations for diabetes management: a pragmatic, factorial, cluster randomized controlled trial [ISRCTN72772651]

Background

Printed educational materials (PEMs) have long been used to inform clinicians on evidence-based practices. However, the evidence for their effects on patient care and outcomes is unclear. In Ontario, despite widely available clinical practice guidelines recommending antihypertensives and cholesterol-lowering agents for patients with diabetes, prescriptions remain low. We aimed to determine whether PEMs can influence physicians to intensify prescribing of these medications.

Methods

A pragmatic, 2 × 2 factorial, cluster randomized controlled trial was designed to ascertain the effect of two PEM formats on physician prescribing: a postcard-sized message (“outsert”) or a longer narrative article (“insert”). Ontario family physician practices (clusters) were randomly allocated to receive the insert, outsert, both or neither. Physicians were eligible if they were in active practice and their patients were included if they were over 65 years with a diabetes diagnosis; both were unaware of the trial. Administrative databases at ICES (formerly the Institute for Clinical Evaluative Sciences) were used to link patients to their physician and to analyse prescribing patterns at baseline and 1 year following PEM mailout. The primary outcome was intensification defined as the addition of a new antihypertensive or cholesterol-lowering agent, or dose increase of a current drug, measured at the patient level. Analyses were by intention-to-treat and accounted for the clustering of patients to physicians.

Results

We randomly assigned 4231 practices (39% of Ontario family physicians) with a total population of 185,526 patients (20% of patients with diabetes in Ontario primary care) to receive the insert, outsert, both, and neither; among these, 4118 practices were analysed (n = 1025, n = 1037, n = 1031, n = 1025, respectively). No significant treatment effect was found for the outsert (odds ratio (OR) 1.01, 95% confidence interval (CI) 0.98 to 1.04) or the insert (OR 0.99, 95% CI 0.96 to 1.02). Percent of intensification in the four arms was similar (approximately 46%). Adjustment for physician characteristics (e.g., age, sex, practice location) had no impact on these findings.

Conclusions

PEMs have no effect on physician’s adherence to recommendations for the management of diabetes-related complications in Ontario. Further research should investigate the effect of other strategies to narrow this evidence-to-practice gap.

Trial registration

ISRCTN72772651. Retrospectively registered 21 July 2005.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01592-9.

Long-Term Kidney Outcomes Following Dialysis-Treated Childhood Acute Kidney Injury: A Population-Based Cohort Study

BACKGROUND

AKI is common during pediatric hospitalizations and associated with adverse short-term outcomes. However, long-term outcomes among survivors of pediatric AKI who received dialysis remain uncertain.

METHODS

To determine the long-term risk of kidney failure (defined as receipt of chronic dialysis or kidney transplant) or death over a 22-year period for pediatric survivors of dialysis-treated AKI, we used province-wide health administrative databases to perform a retrospective cohort study of all neonates and children (aged 0-18 years) hospitalized in Ontario, Canada, from April 1, 1996, to March 31, 2017, who survived a dialysis-treated AKI episode. Each AKI survivor was matched to four hospitalized pediatric comparators without dialysis-treated AKI, on the basis of age, sex, and admission year. We reported the incidence of each outcome and performed Cox proportional hazards regression analyses, adjusting for relevant covariates.

RESULTS

We identified 1688 pediatric dialysis-treated AKI survivors (median age 5 years) and 6752 matched comparators. Among AKI survivors, 53.7% underwent mechanical ventilation and 33.6% had cardiac surgery. During a median 9.6-year follow-up, AKI survivors were at significantly increased risk of a composite outcome of kidney failure or death versus comparators. Death occurred in 113 (6.7%) AKI survivors, 44 (2.6%) developed kidney failure, 174 (12.1%) developed hypertension, 213 (13.1%) developed CKD, and 237 (14.0%) had subsequent AKI. AKI survivors had significantly higher risks of developing CKD and hypertension versus comparators. Risks were greatest in the first year after discharge and gradually decreased over time.

CONCLUSIONS

Survivors of pediatric dialysis-treated AKI are at higher long-term risks of kidney failure, death, CKD, and hypertension, compared with a matched hospitalized cohort.

Learning health systems in primary care: a systematic scoping review

BACKGROUND

Learning health systems have been gaining traction over the past decade. The purpose of this study was to understand the spread of learning health systems in primary care, including where they have been implemented, how they are operating, and potential challenges and solutions.

METHODS

We completed a scoping review by systematically searching OVID Medline®, Embase®, IEEE Xplore®, and reviewing specific journals from 2007 to 2020. We also completed a Google search to identify gray literature.

RESULTS

We reviewed 1924 articles through our database search and 51 articles from other sources, from which we identified 21 unique learning health systems based on 62 data sources. Only one of these learning health systems was implemented exclusively in a primary care setting, where all others were integrated health systems or networks that also included other care settings. Eighteen of the 21 were in the United States. Examples of how these learning health systems were being used included real-time clinical surveillance, quality improvement initiatives, pragmatic trials at the point of care, and decision support. Many challenges and potential solutions were identified regarding data, sustainability, promoting a learning culture, prioritization processes, involvement of community, and balancing quality improvement versus research.

CONCLUSIONS

We identified 21 learning health systems, which all appear at an early stage of development, and only one was primary care only. We summarized and provided examples of integrated health systems and data networks that can be considered early models in the growing global movement to advance learning health systems in primary care.

Opportunities To Improve Diabetes Care in the Hemodialysis Unit: A Cohort Study in Ontario, Canada

Background

Patients with diabetes receiving chronic, in-center hemodialysis face healthcare challenges. We examined the prevalence of gaps in their diabetes care, explored regional differences, and determined predictors of care gaps.

Methods

We conducted a population-based, retrospective study between January 1, 2016 and January 1, 2018 in Ontario, Canada. We included adults with prevalent diabetes mellitus receiving in-center hemodialysis as of January 1, 2018 and examined the proportion with (1) insufficient or excessive glycemic monitoring, (2) suboptimal screening for diabetes-related complications (retinopathy and cardiovascular screening), (3) hospital encounters for hypo- or hyperglycemia, and (4) hospital encounters for hypertension in the 2 years prior (January 1, 2016 to January 1, 2018). We then identified patient, provider, and health-system factors associated with more than one care gap and used multivariable logistic regression to determine predictors. Further, we used geographic information systems to explore spatial variation in gaps.

Results

There were 4173 patients with diabetes receiving in-center hemodialysis; the mean age was 67 years, 39% were women, and the majority were of lower socioeconomic status. Approximately 42% of patients had more than one diabetes care gap, the most common being suboptimal retinopathy screening (53%). Significant predictors of more than one gap included younger age, female sex, shorter duration of diabetes, dementia, fewer specialist visits, and not seeing a physician for diabetes. There was evidence of spatial variation in care gaps across our region.

Conclusions

There are opportunities to improve diabetes care in patients receiving in-center hemodialysis, particularly screening for retinopathy. Focused efforts to bring diabetes support to high-risk individuals might improve their care and outcomes.

Risk of Hospital Encounters With Kidney Stones in Autosomal Dominant Polycystic Kidney Disease: A Cohort Study

Background:

There is a perception that patients with autosomal dominant polycystic kidney disease (ADPKD) are more likely to develop kidney stones than the general population.

Objective:

To compare the rate of hospital encounter with kidney stones and the rate of stone interventions between patients with and without ADPKD.

Design:

Retrospective cohort study.

Setting:

Ontario, Canada.

Patients:

Patients with and without ADPKD who had a prior hospital encounter between 2002 and 2016.

Measurements:

Rate of hospital encounter with kidney stones and rate of stone intervention.

Methods:

We used inverse probability exposure weighting based on propensity scores to balance baseline indicators of health between patients with and without ADPKD. We followed each patient until death, emigration, outcomes, or March 31, 2017. We used a Cox proportional hazards model to compare event rates between the two groups.

Results:

Patients with ADPKD were at higher risk of hospital encounter with stones compared with patients without ADPKD (81 patients of 2094 with ADPKD [3.8%] vs 60 patients of 1902 without ADPKD [3.2%]; 8.9 vs 5.1 events per 1000 person-years; hazard ratio 1.6 [95% CI, 1.3-2.1]). ADPKD was not associated with a higher risk of stone intervention (49 of 2094 [2.3%] vs 47 of 1902 [2.4%]; 5.3 vs 3.9 events per 1000 person-years; hazard ratio 1.2 [95% CI = 0.9-1.3]).

Limitations:

We did not have information on kidney stone events outside of the hospital. There is a possibility of residual confounding.

Conclusion:

ADPKD was a significant risk factor for hospital encounters with kidney stones.

Complications in Patients With Autosomal Dominant Polycystic Kidney Disease Undergoing Ureteroscopy: A Cohort Study

BACKGROUND

Ureteroscopy is a minimally invasive treatment option for upper tract stones. The distorted kidney anatomy in patients with autosomal dominant polycystic kidney disease (ADPKD) may place them at higher risk for ureteroscopic complications.

OBJECTIVE

To compare the 30-day risk of ureteroscopic complications between patients with and without ADPKD.

DESIGN

Retrospective cohort study.

SETTING

Ontario, Canada.

PATIENTS

Seventy three patients with ADPKD and 81 445 patients without ADPKD who underwent ureteroscopy for upper urinary tract stones between April 1, 2002, and March 1, 2018.

MEASUREMENTS

A 30-day risk of (1) hospital presentation with ureteroscopic complications (which was a composite outcome of either emergency department visit or hospital admission with acute kidney injury, urinary tract infection, or sepsis); (2) all-cause hospital presentation; (3) all-cause hospital admission; and (4) all-cause emergency department visit.

METHODS

We regressed outcomes on demographic variables, health care use in the prior 1-year, various procedures and comorbidities related to the outcome in the prior 5 years, and prescribed medications filled in the past 120 days using modified Poisson regression to compare the risk ratio (RR) of each outcome between patients with and without ADPKD.

RESULTS

The median (interquartile, IQR) age was 44 (38-60 years) in the ADPKD group and 53 (42-64) in the control group. About 40% were women in both groups. The risk of ureteroscopic complications was not significantly different in patients with versus without ADPKD (8.2% vs 4.3%; adjusted RR = 1.5, 95% confidence interval [CI] = 0.7-3.2). Patients with versus without ADPKD were more likely to present to hospital after their procedure (35.6% vs. 20.0%; adjusted RR = 1.6, 95% CI = 1.2-2.2), which included a statistically significant increase in the risk of presenting to the emergency department (32.9% vs. 19.0%; adjusted RR = 1.6, 95% CI = 1.1-2.2) but not hospital admissions (10.9% vs. 5.0%; adjusted RR = 1.8, 95% CI = 0.9-3.4).

LIMITATIONS

The low numbers of events led to imprecision around the estimates.

CONCLUSION

Patients with ADPKD have a higher risk of return to the hospital within 30 days of ureteroscopy for stone disease.

TRIAL REGISTRATION

We did not register this study.

Kidney Function and Potassium Monitoring After Initiation of Renin-Angiotensin-Aldosterone System Blockade Therapy and Outcomes in 2 North American Populations

BACKGROUND

Clinical practice guidelines recommend routine kidney function and serum potassium testing within 30 days of initiating ACE (angiotensin-converting enzyme) inhibitor or angiotensin II receptor blocker therapy. However, evidence is lacking about whether follow-up testing reduces therapy-related adverse outcomes.

METHODS AND RESULTS

We conducted 2 population-based retrospective cohort studies in Kaiser Permanente Northern California and Ontario, Canada. Patients with outpatient serum creatinine and potassium tests in the 30 days after starting ACE inhibitor or angiotensin II receptor blocker therapy were matched 1:1 to patients without follow-up tests. We evaluated the association of follow-up testing with 30-day all-cause mortality and hospitalization with acute kidney injury or hyperkalemia using Cox regression. We also developed and externally validated a risk score to identify patients at risk of having abnormally high serum creatinine and potassium values in follow-up. We identified 75 251 matched pairs initiating ACE inhibitor or angiotensin II receptor blocker therapy between January 1, 2007, and December 31, 2017, in Kaiser Permanente Northern California. Follow-up testing was not significantly associated with 30-day all-cause mortality in Kaiser Permanente Northern California (hazard ratio, 0.75 [95% CI, 0.54-1.06]) and was associated with higher mortality in 84 905 matched pairs in Ontario (hazard ratio, 1.32 [95% CI, 1.07-1.62]). In Kaiser Permanente Northern California, follow-up testing was significantly associated with higher rates of hospitalization with acute kidney injury (hazard ratio, 1.66 [95% CI, 1.10-2.22]) and hyperkalemia (hazard ratio, 3.36 [95% CI, 1.08-10.41]), as was observed in Ontario. The risk score for abnormal potassium provided good discrimination (area under the curve [AUC], 0.75) and excellent calibration of predicted risks, while the risk score for abnormal serum creatinine provided moderate discrimination (AUC, 0.62) but excellent calibration.

CONCLUSIONS

Routine laboratory monitoring after ACE inhibitor or angiotensin II receptor blocker initiation was not associated with a lower risk of 30-day mortality. We identified patient subgroups in which targeted testing may be effective in identifying therapy-related changes in serum potassium or kidney function.

Efficacy and Safety of Surgical Kidney Stone Interventions in Autosomal Dominant Polycystic Kidney Disease: A Systematic Review

BACKGROUND

Reduced kidney function and distorted kidney anatomy in patients with autosomal dominant polycystic kidney disease (ADPKD) may complicate stone interventions more compared with the general population.

OBJECTIVES

To review studies describing the safety and efficacy of the 3 main stone interventions in adults with ADPKD: shock wave lithotripsy (SWL), ureteroscopy, and percutaneous nephrolithotomy (PCNL).

DESIGN

Systematic review.

SETTING

Any country of origin.

PATIENTS

Adults with ADPKD who underwent SWL, ureteroscopy, or PCNL.

MEASUREMENTS

Being stone free after the intervention and postoperative complications as reported by each study, which included pain, bleeding, and fever.

METHODS

Relevant studies published until February 2019 were identified through a comprehensive search of MEDLINE, EMBASE, Web of Science, BIOSIS PREVIEW, and CINAHL. Studies were eligible for review if they reported at least one outcome following SWL, ureteroscopy, and/or PCNL in adults with ADPKD. We then abstracted information on study characteristics, patient characteristics, intervention details, and postintervention outcomes and assessed the methodological quality of each study using a modified Downs and Black checklist.

RESULTS

We screened 221 citations from which we identified 24 studies that met our review criteria. We identified an additional article when manually reviewing the reference list of an included article, yielding a total of 25 studies describing 311 patients (32 SWL, 42 ureteroscopy, and 237 PCNL). The percentage of patients who were stone free after 1 session ranged from 0% to 69% after SWL, 73% to 100% after ureteroscopy, and 45% to 100% after PCNL. The percentage of patients with ADPKD that experienced at least one postoperative complication ranged from 0% to 33% for SWL, 0% to 27% for ureteroscopy, and 0% to 100% for PCNL.

LIMITATIONS

The number and quality of studies published to date are limited.

CONCLUSIONS

The efficacy and safety of stone interventions in patients with ADPKD remains uncertain, with wide-ranging estimates reported in the literature.

TRIAL REGISTRATION

We did not register the protocol of this systematic review.

Acute Kidney Injury in Patients Receiving Systemic Treatment for Cancer: A Population-Based Cohort Study

BACKGROUND

Patients undergoing treatment for cancer are at increased risk of acute kidney injury (AKI). There are few data on AKI incidence and risk factors in the current era of cancer treatment.

METHODS

We conducted a population-based study of all patients initiating systemic therapy (chemotherapy or targeted agents) for a new cancer diagnosis in Ontario, Canada (2007-2014). The primary outcome was hospitalization with AKI or acute dialysis. We estimated the cumulative incidence of AKI and fitted Fine and Gray models, adjusting for demographics, cancer characteristics, comorbidities, and coprescriptions. We modeled exposure to systemic therapy (the 90-day period following treatments) as a time-varying covariate. We also assessed temporal trends in annual AKI incidence.

RESULTS

We identified 163 071 patients initiating systemic therapy of whom 10 880 experienced AKI. The rate of AKI was 27 per 1000 person-years, with overall cumulative incidence of 9.3% (95% CI = 9.1% to 9.6%). Malignancies with the highest 5-year AKI incidence were myeloma (26.0%, 95% CI = 24.4% to 27.7%), bladder (19.0%, 95% CI = 17.6% to 20.5%), and leukemia (15.4%, 95% CI = 14.3% to 16.5%). Advanced cancer stage, chronic kidney disease, and diabetes were associated with increased risk of AKI (adjusted hazard ratios [aHR] = 1.41, 95% CI = 1.28 to 1.54; 1.80, 95% CI = 1.67 to 1.93; and 1.43, 95% CI = 1.37 to 1.50, respectively). In patients aged 66 years or older with universal drug benefits, diuretic, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker coprescription was associated with higher AKI risk (aHR = 1.20, 95% CI = 1.14 to 1.28; 1.30, 95% CI = 1.23 to 1.38). AKI risk was further accentuated during the 90-day period following systemic therapy (aHR = 2.34, 95% CI = 2.24 to 2.45). The annual incidence of AKI increased from 18 to 52 per 1000 person-years between 2007 and 2014.

CONCLUSION

Cancer-related AKI is common and associated with advanced stage, chronic kidney disease, diabetes, and concomitant receipt of diuretics or angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. Risk is heightened in the 90 days after systemic therapy. Preventive strategies are needed to address the increasing burden of AKI in this population.

Partial vs. radical nephrectomy and the risk of all-cause mortality, cardiovascular, and nephrological outcomes

INTRODUCTION

The study's objective was to examine the effects of renal-preservation surgery on long-term mortality, cardiovascular outcomes, and renal-related outcomes.

METHODS

We performed a retrospective cohort study of all partial (n=575) and radical nephrectomies (n=882) for tumors ≤7 cm in diameter between 2002 and 2010 across three academic centers in Ontario, Canada. We linked records from provincial databases to assess patient characteristics and outcomes (median seven years' followup using retrospective data). A weighted propensity score was used to reduce confounding. The primary outcome was all-cause mortality. Secondary outcomes included hospitalization with major cardiovascular events, non-cancer related mortality, kidney cancer-related mortality, and dialysis.

RESULTS

Mean one-year postoperative estimated glomerular filtration rate (eGFR) was 71 mL/min/1.73 m² in the partial group and 52 mL/min/1.73 m² in the radical group. Partial nephrectomy was associated with a lower risk of all-cause mortality in the first five years after surgery (hazard ratio [HR] 0.42, 95% confidence interval [CI] 0.27-0.66), which did not extend beyond five years (HR 1.01, 95% CI 0.68-1.49). Kidney cancer-related mortality was lower in the partial compared to the radical group for the first four years after surgery (HR 0.16, 95% CI 0.04-0.72). There were no significant differences between the groups for cardiovascular outcomes or non-cancer related deaths.

CONCLUSIONS

Overall survival and cancer-specific survival was reduced in radical nephrectomy patients. However, despite reduced renal function in the radical nephrectomy group, non-cancer-related death, cardiovascular events, and dialysis were not significantly different between groups. Long-term benefits of partial nephrectomy may be less than previously believed.

Impact of the KidneyWise toolkit on chronic kidney disease referral practices in Ontario primary care: a prospective evaluation

OBJECTIVES

Chronic kidney disease (CKD) is common; therefore, coordination of care between primary care and nephrology is important. Ontario Renal Network's KidneyWise toolkit was developed to provide guidance on the detection and management of people with CKD in primary care (www.kidneywise.ca). The aim of this study was to evaluate the impact of the April 2015 KidneyWise toolkit release on the characteristics of primary care referrals to nephrology.

DESIGN AND SETTING

The study was a prospective pre-post design conducted at two nephrology sites (community site: Trillium Health Partners in Mississauga, Ontario, Canada, and academic site: St Joseph's Healthcare in Hamilton, Ontario, Canada). Referrals were compared during the 3-month time period immediately prior to, and during a 3-month period 1 year after, the toolkit release.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the change in proportion of referrals for CKD that met the KidneyWise criteria. Additional secondary referral and quality of care outcomes were also evaluated. Multivariable logistic regression was used to evaluate preselected variables for their independent association with referrals that met the KidneyWise criteria.

RESULTS

The proportion of referrals for CKD among people who met the KidneyWise referral criteria did not significantly change from pre-KidneyWise to post-KidneyWise implementation (44.7% vs 45.8%, respectively, adjusted OR 1.16, 95% CI 0.85 to 1.59, p=0.36). The proportion of referrals for CKD that provided a urine albumin-creatinine ratio significantly increased post-KidneyWise (25.8% vs 43.8%, adjusted OR 1.45, 95% CI 1.06 to 1.97, p=0.02). The significant independent predictors of meeting the KidneyWise referral criteria were academic site, increased age and use of the KidneyWise referral form.

CONCLUSIONS

We did not observe any change in the proportion of appropriate referrals for CKD at two large nephrology centres 1 year after implementation of the KidneyWise toolkit.

Incidence and outcomes of invasive fungal infection among solid organ transplant recipients: A population-based cohort study

BACKGROUND

Invasive fungal infection (IFI) in solid organ transplant (SOT) recipients is associated with significant morbidity and mortality. The long-term probability of post-transplant IFI is poorly understood.

METHODS

We conducted a population-based cohort study using linked administrative healthcare databases from Ontario, Canada, to determine the incidence rate; 1-, 5-, and 10-year cumulative probabilities of IFI; and post-IFI all-cause mortality in SOT recipients from 2002 to 2016. We also determined post-IFI, death-censored renal allograft failure.

RESULTS

We included 9326 SOT recipients (median follow-up: 5.35 years). Overall, the incidence of IFI was 8.3 per 1000 person-years. The 1-year cumulative probability of IFI was 7.4% for lung, 5.4% for heart, 1.8% for liver, 1.2% for kidney-pancreas, and 1.1% for kidney-only allograft recipients. Lung transplant recipients had the highest incidence rate and 10-year probability of IFI: 43.0 per 1000 person-years and 26.4%, respectively. The 1-year all-cause mortality rate after IFI was 34.3%. IFI significantly increased the risk of mortality in SOT recipients over the entire follow-up period (hazard ratio: 6.50, 95% CI: 5.69-7.42). The 1-year probability of death-censored renal allograft failure after IFI was 9.8%.

CONCLUSION

Long-term cumulative probability of IFI varies widely among SOT recipients. Lung transplantation was associated with the highest incidence of IFI with considerable 1-year all-cause mortality.

Diagnostic accuracy of administrative codes for autosomal dominant polycystic kidney disease in clinic patients with cystic kidney disease

Background

The ability to identify patients with autosomal dominant polycystic kidney disease (ADPKD) and distinguish them from patients with similar conditions in healthcare administrative databases is uncertain. We aimed to measure the sensitivity and specificity of different ADPKD administrative coding algorithms in a clinic population with non-ADPKD and ADPKD kidney cystic disease.

Methods

We used a dataset of all patients who attended a hereditary kidney disease clinic in Toronto, Ontario, Canada between 1 January 2010 and 23 December 2014. This dataset included patients who met our reference standard definition of ADPKD or other cystic kidney disease. We linked this dataset to healthcare databases in Ontario. We developed eight algorithms to identify ADPKD using the International Classification of Diseases, 10th Revision (ICD-10) codes and provincial diagnostic billing codes. A patient was considered algorithm positive if any one of the codes in the algorithm appeared at least once between 1 April 2002 and 31 March 2015.

Results

The ICD-10 coding algorithm had a sensitivity of 33.7% [95% confidence interval (CI) 30.0–37.7] and a specificity of 86.2% (95% CI 75.7–92.5) for the identification of ADPKD. The provincial diagnostic billing code had a sensitivity of 91.1% (95% CI 88.5–93.1) and a specificity of 10.8% (95% CI 5.3–20.6).

Conclusions

ICD-10 coding may be useful to identify patients with a high chance of having ADPKD but fail to identify many patients with ADPKD. Provincial diagnosis billing codes identified most patients with ADPKD and also with other types of cystic kidney disease.

Nephrology comanagement and the quality of antibiotic prescribing in primary care for patients with chronic kidney disease: a retrospective cross-sectional study

BACKGROUND

In primary care, patients with chronic kidney disease (CKD) are frequently prescribed excessive doses of antibiotics relative to their kidney function. We examined whether nephrology comanagement is associated with improved prescribing in primary care.

METHODS

In a retrospective propensity score-matched cross-sectional study, we studied the appropriateness of antibiotic prescriptions by primary care physicians to Ontarians ≥66 years of age with CKD Stages 4 and 5 (estimated glomerular filtration rate <30 mL/min/1.73 m2 not receiving dialysis) from 1 April 2003 to 31 March 2014. Comanagement was defined as having at least one outpatient visit with a nephrologist within the year prior to antibiotic prescription date. We compared the rate of appropriately dosed antibiotics in primary care between 3937 patients who were comanaged by a nephrologist and 3937 patients who were not.

RESULTS

Only 1184 (30%) of 3937 noncomanaged patients had appropriately dosed antibiotic prescriptions prescribed by a primary care physician. Nephrology comanagement was associated with an increased likelihood that an appropriately dosed prescription was prescribed by a primary care physician; however, the magnitude of the effect was modest [1342/3937 (34%); odds ratio 1.20 (95% confidence interval 1.09-1.32); P < 0.001].

CONCLUSION

The majority of antibiotics prescribed by primary care physicians are inappropriately dosed in CKD patients, whether or not a nephrologist is comanaging the patient. Nephrologists have an opportunity to increase awareness of appropriate dosing of medications in primary care through the patients they comanage.

Stone Prevalence in Autosomal Dominant Polycystic Kidney Disease: A Systematic Review and Meta-Analysis

Background:

It is uncertain how often patients with autosomal dominant polycystic kidney disease (ADPKD) develop kidney stones.

Objective:

To review English-language studies reporting the incidence and prevalence of stones and stone interventions in adults with ADPKD.

Design:

Systematic review and meta-analysis.

Setting:

Any country of origin.

Patients:

Adult patients with ADPKD.

Measurements:

Incidence or prevalence of kidney stones and stone interventions.

Methods:

We reviewed 1812 citations from bibliographic databases, abstracted data from 49 eligible studies, and assessed methodological quality in duplicate. In some studies, the proportion of adults with ADPKD with the outcome were compared to adults without ADPKD; for these studies, prevalence risk ratios were calculated and pooled using a random effects model.

Results:

We identified 49 articles that met our review criteria. The methodological quality of many studies was limited (scores ranging from 2 to 14 out of 22, with a higher score indicating higher quality). No study clearly reported stone incidence, and in the cross-sectional studies, the definition of stones was often unclear. The prevalence of stones ranged from 3% to 59%, and a prevalence of stone interventions ranged from 1% to 8%; the average patient age at the time of assessment ranged from 26 to 61 years across the studies. Two studies reported a nonstatistically significant higher stone prevalence in patients with ADPKD compared to unaffected family members. Compared to unaffected family members, patients with ADPKD had a higher prevalence of kidney stones (6 cross-sectional studies; unadjusted prevalence ratio: 1.8; 95% confidence interval: 1.3 to 2.6; P = .0007; test for heterogeneity: I² = 0%, P = .8).

Limitations:

Studies were limited to articles published in English.

Conclusions:

The prevalence of kidney stones and stone interventions in adults with ADPKD remains uncertain. Future studies of higher methodological quality are needed to better characterize the incidence and prevalence of kidney stones in patients with ADPKD.

Trial registration:

We did not register the protocol for this systematic review.

Predicting mortality among critically ill patients with acute kidney injury treated with renal replacement therapy: Development and validation of new prediction models

PURPOSE

Severe acute kidney injury (AKI) is associated with a significant risk of mortality and persistent renal replacement therapy (RRT) dependence. The objective of this study was to develop prediction models for mortality at 90-day and 1-year following RRT initiation in critically ill patients with AKI.

METHODS

All patients who commenced RRT in the intensive care unit for AKI at a tertiary care hospital between 2007 and 2014 constituted the development cohort. We evaluated the external validity of our mortality models using data from the multicentre OPTIMAL-AKI study.

RESULTS

The development cohort consisted of 594 patients, of whom 320(54%) died and 40 (15% of surviving patients) remained RRT-dependent at 90-day Eleven variables were included in the model to predict 90-day mortality (AUC:0.79, 95%CI:0.76-0.82). The performance of the 90-day mortality model declined upon validation in the OPTIMAL-AKI cohort (AUC:0.61, 95%CI:0.54-0.69) and showed modest calibration. Similar results were obtained for mortality model at 1-year.

CONCLUSIONS

Routinely collected variables at the time of RRT initiation have limited ability to predict mortality in critically ill patients with AKI who commence RRT.

The Frequency of Routine Blood Sampling and Patient Outcomes Among Maintenance Hemodialysis Recipients

RATIONALE & OBJECTIVE

Surveillance blood work is routinely performed in maintenance hemodialysis (HD) recipients. Although more frequent blood testing may confer better outcomes, there is little evidence to support any particular monitoring interval.

STUDY DESIGN

Retrospective population-based cohort study.

SETTING & PARTICIPANTS

All prevalent HD recipients in Ontario, Canada, as of April 1, 2011, and a cohort of incident patients commencing maintenance HD in Ontario, Canada, between April 1, 2011, and March 31, 2016.

EXPOSURE

Frequency of surveillance blood work, monthly versus every 6 weeks.

OUTCOMES

The primary outcome was all-cause mortality. Secondary outcomes were major adverse cardiovascular events, all-cause hospitalization, and episodes of hyperkalemia.

ANALYTICAL APPROACH

Cox proportional hazards with adjustment for demographic and clinical characteristics was used to evaluate the association between blood testing frequency and all-cause mortality. Secondary outcomes were evaluated using the Andersen-Gill extension of the Cox model to allow for potential recurrent events.

RESULTS

7,454 prevalent patients received care at 17 HD programs with monthly blood sampling protocols (n=5,335 patients) and at 8 programs with blood sampling every 6 weeks (n=2,119 patients). More frequent monitoring was not associated with a lower risk for all-cause mortality compared to blood sampling every 6 weeks (adjusted HR, 1.16; 95% CI, 0.99-1.38). Monthly monitoring was not associated with a lower risk for any of the secondary outcomes. Results were consistent among incident HD recipients.

LIMITATIONS

Unmeasured confounding; limited data for center practices unrelated to blood sampling frequency; no information on frequency of unscheduled blood work performed outside the prescribed sampling interval.

CONCLUSIONS

Monthly routine blood testing in HD recipients was not associated with a lower risk for death, cardiovascular events, or hospitalizations as compared with testing every 6 weeks. Given the health resource implications, the frequency of routine blood sampling in HD recipients deserves careful reassessment.

Kidney disease and care among First Nations people with diabetes in Ontario: a population-based cohort study

BACKGROUND

End-stage kidney disease is a serious complication of diabetes. We describe the prevalence of chronic kidney disease, prevalence and incidence of end-stage kidney disease and quality of care of early-stage chronic kidney disease for First Nations people with diabetes compared to other Ontarians with diabetes.

METHODS

We conducted a retrospective cohort study in Ontario using linked administrative data at ICES. We included adults with incident diabetes between 1994 and 2014, and used laboratory values to identify kidney disease and quality indicators for care for early-stage disease. We compared measures in First Nations people to those in other people in Ontario, and used direct age and sex standardization. We used Cox proportional hazards regression to compare the incidence of end-stage kidney disease between groups.

RESULTS

Our study included 21 968 First Nations people with diabetes. The age- and sex-standardized prevalence of chronic kidney disease was higher for First Nations people than for other Ontarians (20.7% v. 18.4%), as was the prevalence of end-stage kidney disease (2.9% v. 1.0%). The incidence of end-stage kidney disease was higher among First Nations people than among other people in Ontario (9.3 v. 4.7 events per 10 000 person-years; age- and sex-adjusted hazard ratio 2.23, 95% confidence interval 1.72-2.89). The 2 groups were similarly likely to receive recommended medications, but First Nations people were less likely to receive laboratory tests for their kidney disease.

INTERPRETATION

Despite receiving similar quality of care for early-stage kidney disease, First Nations people with diabetes had higher rates of end-stage kidney disease than other Ontarians. Further research is needed to better understand contributing factors to help inform future interventions.

Identifying Ontario geographic regions to assess adults who present to hospital with laboratory-defined conditions: a descriptive study

BACKGROUND

In 2007, an electronic repository called the Ontario Laboratories Information System (OLIS) was introduced to allow health care providers timely access to laboratory test results. Since not all laboratories began submitting their data to OLIS simultaneously, we sought to create a date-dependent table of geographic regions (forward sortation areas [FSAs]) from which people would likely present to a hospital linked to OLIS.

METHODS

In this descriptive study, we used administrative data to capture adults in Ontario who presented to the emergency department for any reason from 2007 to 2017. To assess changes over time, we classified all emergency department visits into fiscal quarters. The primary outcome measure was the proportion of people in a given FSA presenting to an emergency department at an OLIS-linked hospital (v. a hospital not linked to OLIS). To be included in the catchment area, at least 90% of all emergency department visits in a given quarter from a given FSA must have occurred at an OLIS-linked hospital.

RESULTS

By Dec. 31, 2017, 323 (61.4%) of 526 Ontario FSAs were in the catchment area (a population of about 8.5 million). There were no differences in selected demographic characteristics or comorbidities between people residing within the catchment area of OLIS-linked hospitals and those residing in the catchment area of unlinked hospitals on Dec. 31, 2017. We used the FSA information to construct a date-dependent table of geographic areas likely to have hospital laboratory data available in OLIS for future studies.

INTERPRETATION

We identified relevant Ontario geographic regions from which people would likely present to a hospital linked to OLIS. These geographic regions constitute a catchment area that may be used in future studies to capture adults who present to an OLIS-linked hospital with laboratory-defined conditions such as acute kidney injury, hyperkalemia and hyponatremia.

Direct Exports of Phosphorus from Fertilizers Applied to Grazed Pastures

Since its discovery in 1669, phosphorus (P) in the form of fertilizer has become an essential input for many agroecosystems. By introducing a concentrated P source, fertilizers increase short-term P export potential soon after their application and longer-term export potential by increasing soil fertility (legacy P). The 4R concept was developed to help mitigate P exports from the fertilizers that sustain agricultural productivity. This review investigates the factors affecting P exports soon after the application of mineral fertilizers to pasture-based grazing systems and studies quantifying its potential impact in different systems, with an emphasis on Australasia. Initially, P fertilizers and reactions that might affect their short-term P export potential are reviewed, along with P transport pathways, the forms of P exported from grazing systems, factors affecting P mobilization into water, and studies demonstrating the possible short-term effects of fertilizer application on P exports. Using that foundation, we review studies quantifying the short-term impact of fertilizer application in different regions; they show that under poor management, recently applied fertilizer can contribute a considerable proportion (30-80%) of total farm P exports in drainage, but when fertilizer is well-managed, that figure is expected to be <10%. We then use three model systems of varying hydrology that are common to Australasia to demonstrate the principles for selecting fertilizers that are likely to minimize P exports soon after their application.

Nonsteroidal anti-inflammatory drug use and risk of acute kidney injury and hyperkalemia in older adults: a population-based study

BACKGROUND

Clinical guidelines caution against nonsteroidal anti-inflammatory drug (NSAID) use in older adults. The study objective was to quantify the 30-day risk of acute kidney injury (AKI) and hyperkalemia in older adults after NSAID initiation and to develop a model to predict these outcomes.

METHODS

We conducted a population-based retrospective cohort study in Ontario, Canada from 2007 to 2015 of patients ≥66 years. We matched 46 107 new NSAID users with 46 107 nonusers with similar baseline health. The primary outcome was 30-day risk of AKI and secondary outcomes were hyperkalemia and all-cause mortality.

RESULTS

NSAID use versus nonuse was associated with a higher 30-day risk of AKI {380 [0.82%] versus 272 [0.59%]; odds ratio (OR) 1.41 [95% confidence interval (CI) 1.20-1.65]} and hyperkalemia [184 (0.40%) versus 123 (0.27%); OR 1.50 (95% CI 1.20-1.89); risk difference 0.23% (95% CI 0.13-0.34)]. There was no association between NSAID use and all-cause mortality. A prediction model incorporated six predictors of AKI or hyperkalemia: older age, male gender, lower baseline estimated glomerular filtration rate, higher baseline serum potassium, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use or diuretic use. This model had moderate discrimination [C-statistic 0.72 (95% CI 0.70-0.74)] and good calibration.

CONCLUSIONS

In older adults, new NSAID use compared with nonuse was associated with a higher 30-day risk of AKI and hyperkalemia but not all-cause mortality. Prescription NSAID use among many older adults may be safe, but providers should use caution and assess individual risk.

Primary care provider perceptions of enablers and barriers to following guideline-recommended laboratory tests to confirm chronic kidney disease: a qualitative descriptive study

Background

Patients should receive follow-up serum creatinine tests after an initial abnormal result to diagnose chronic kidney disease. However, half of the time this fails to occur in primary care. We interviewed primary care providers to better understand their perceptions of enablers and barriers to following this guideline-recommended care.

Methods

We performed a qualitative descriptive study guided by the Theoretical Domains Framework (TDF), a framework for behavioural change. We used purposeful sampling to recruit primary care providers (physicians and nurse practitioners) based on provider and practice characteristics (rural, solo versus team practice, etc.) from Ontario, Canada. We completed one-on-one interviews with providers using a semi-structured and open-ended interview guide based on the 14 TDF domains. We alternated between data collection and analysis, where we used directed content analysis to identify frequent, important, and conflicting enablers and barriers.

Results

We completed 13 interviews with nine primary care physicians and four nurse practitioners. Nine themes related to the TDF emerged from the data: 1) environmental context and resources, 2) knowledge, 3) memory, attention, and decision processes, 4) beliefs about consequences, 5) goals, 6) social or professional role, 7) behavioural regulation, 8) skills, and 9) optimism. Within these themes, we identified 16 enablers and five barriers. Some enablers included, providers’ knowledge on appropriate testing, their motivation to order these tests, and their use of tools and resources to help order follow-up serum creatinine tests. However, providers perceived some barriers including that ordering confirmatory laboratory tests for chronic kidney disease was not always a priority in regards to other care they wish to provide. Providers also noted that a perceived barrier is patients not going to the laboratory to complete the test.

Conclusions

We identified novel enablers and barriers to primary care providers completing guideline recommended repeat testing for the diagnosis of chronic kidney disease. Similar research is needed to understand the views of patients. These research findings can be used to inform strategies to improve the quality of care.

Electronic supplementary material

The online version of this article (10.1186/s12875-018-0879-2) contains supplementary material, which is available to authorized users.

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.

The Health and Health Care of Adults With Type 1 And 2 Diabetes Across the Spectrum of Estimated Glomerular Filtration Rates

OBJECTIVES

Little is known about the health and health-care patterns of patients with diabetes according to their estimated glomerular filtration rates, especially within a publicly funded health-care system.

METHODS

Using linked health-care databases in Ontario, Canada, we performed a population-based study of adults 50 years of age and older (mean age, 68 years) with prevalent diabetes on January 1, 2014. We categorized patients according to their levels of kidney function (estimated glomerular filtration rate ≥90, 60 to 89, 30 to 59, 15 to 29 or <15 mL/min/1.73 m², or the receipt of ongoing maintenance dialysis). We then followed patients for 2 years to determine: 1) their level of contact with health-care providers (i.e. visits to family doctors, specialists); 2) their use and repeated use of acute medical services (i.e. hospitalizations and emergency department encounters; 3) diabetes-related monitoring and screening (i.e. glycated hemoglobin and cholesterol tests, vision screening); 4) glycemic and lipid control; and 5) diabetes-related outcomes.

RESULTS

There were 569,384 patients in our study. Most had estimated glomerular filtration rates between 60 and 89 mL/min/1.73 m². At baseline, patients with lower kidney function had longer durations of diabetes and more comorbidities. Over 2 years of follow up, they had higher burdens of medical care, excessive diabetes monitoring and were underscreened for diabetes-related complications. Although metabolic control was reasonable across groups, patients with low kidney function had more hospital encounters and more diabetes-related complications.

CONCLUSIONS

Patients with diabetes and low kidney function are a vulnerable population that faces health system challenges and care gaps. Suggestions for policy and practice are discussed.

Predicting timing of clinical outcomes in patients with chronic kidney disease and severely decreased glomerular filtration rate

Patients with chronic kidney disease and severely decreased glomerular filtration rate (GFR) are at high risk for kidney failure, cardiovascular disease (CVD) and death. Accurate estimates of risk and timing of these clinical outcomes could guide patient counseling and therapy. Therefore, we developed models using data of 264,296 individuals in 30 countries participating in the international Chronic Kidney Disease Prognosis Consortium with estimated GFR (eGFR)s under 30 ml/min/1.73m2. Median participant eGFR and urine albumin-to-creatinine ratio were 24 ml/min/1.73m2 and 168 mg/g, respectively. Using competing-risk regression, random-effect meta-analysis, and Markov processes with Monte Carlo simulations, we developed two- and four-year models of the probability and timing of kidney failure requiring kidney replacement therapy (KRT), a non-fatal CVD event, and death according to age, sex, race, eGFR, albumin-to-creatinine ratio, systolic blood pressure, smoking status, diabetes mellitus, and history of CVD. Hypothetically applied to a 60-year-old white male with a history of CVD, a systolic blood pressure of 140 mmHg, an eGFR of 25 ml/min/1.73m2 and a urine albumin-to-creatinine ratio of 1000 mg/g, the four-year model predicted a 17% chance of survival after KRT, a 17% chance of survival after a CVD event, a 4% chance of survival after both, and a 28% chance of death (9% as a first event, and 19% after another CVD event or KRT). Risk predictions for KRT showed good overall agreement with the published kidney failure risk equation, and both models were well calibrated with observed risk. Thus, commonly-measured clinical characteristics can predict the timing and occurrence of clinical outcomes in patients with severely decreased GFR.

Validity of administrative database code algorithms to identify vascular access placement, surgical revisions, and secondary patency

BACKGROUND:

We assessed the validity of physician billing codes and hospital admission using International Classification of Diseases 10th revision codes to identify vascular access placement, secondary patency, and surgical revisions in administrative data.

METHODS:

We included adults (≥18 years) with a vascular access placed between 1 April 2004 and 31 March 2013 at the University Health Network, Toronto. Our reference standard was a prospective vascular access database (VASPRO) that contains information on vascular access type and dates of placement, dates for failure, and any revisions. We used VASPRO to assess the validity of different administrative coding algorithms by calculating the sensitivity, specificity, and positive predictive values of vascular access events.

RESULTS:

The sensitivity (95% confidence interval) of the best performing algorithm to identify arteriovenous access placement was 86% (83%, 89%) and specificity was 92% (89%, 93%). The corresponding numbers to identify catheter insertion were 84% (82%, 86%) and 84% (80%, 87%), respectively. The sensitivity of the best performing coding algorithm to identify arteriovenous access surgical revisions was 81% (67%, 90%) and specificity was 89% (87%, 90%). The algorithm capturing arteriovenous access placement and catheter insertion had a positive predictive value greater than 90% and arteriovenous access surgical revisions had a positive predictive value of 20%. The duration of arteriovenous access secondary patency was on average 578 (553, 603) days in VASPRO and 555 (530, 580) days in administrative databases.

CONCLUSION:

Administrative data algorithms have fair to good operating characteristics to identify vascular access placement and arteriovenous access secondary patency. Low positive predictive values for surgical revisions algorithm suggest that administrative data should only be used to rule out the occurrence of an event.

Causes of Death after a Hospitalization with AKI

Mortality after AKI is high, but the causes of death are not well described. To better understand causes of death in patients after a hospitalization with AKI and to determine patient and hospital factors associated with mortality, we conducted a population-based study of residents in Ontario, Canada, who survived a hospitalization with AKI from 2003 to 2013. Using linked administrative databases, we categorized cause of death in the year after hospital discharge as cardiovascular, cancer, infection-related, or other. We calculated standardized mortality ratios to compare the causes of death in survivors of AKI with those in the general adult population and used Cox proportional hazards modeling to estimate determinants of death. Of the 156,690 patients included, 43,422 (28%) died in the subsequent year. The most common causes of death were cardiovascular disease (28%) and cancer (28%), with respective standardized mortality ratios nearly six-fold (5.81; 95% confidence interval [95% CI], 5.70 to 5.92) and eight-fold (7.87; 95% CI, 7.72 to 8.02) higher than those in the general population. The highest standardized mortality ratios were for bladder cancer (18.24; 95% CI, 17.10 to 19.41), gynecologic cancer (16.83; 95% CI, 15.63 to 18.07), and leukemia (14.99; 95% CI, 14.16 to 15.85). Along with older age and nursing home residence, cancer and chemotherapy strongly associated with 1-year mortality. In conclusion, cancer-related death was as common as cardiovascular death in these patients; moreover, cancer-related deaths occurred at substantially higher rates than in the general population. Strategies are needed to care for and counsel patients with cancer who experience AKI.

Quality of Care for Patients With Chronic Kidney Disease in the Primary Care Setting: A Retrospective Cohort Study From Ontario, Canada

BACKGROUND

Patients with chronic kidney disease may not be receiving recommended primary renal care.

OBJECTIVE

To use recently established primary care quality indicators for chronic kidney disease to determine the proportion of patients receiving recommended renal care.

DESIGN

Retrospective cohort study using administrative data with linked laboratory information.

SETTING

The study was conducted in Ontario, Canada, from 2006 to 2012.

PATIENTS

Patients over 40 years with chronic kidney disease or abnormal kidney function in primary care were included.

MEASUREMENTS

In total, 11 quality indicators were assessed for chronic kidney disease identified through a Delphi panel in areas of screening, monitoring, drug prescribing, and laboratory monitoring after initiating an angiotensin converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB).

METHODS

We calculated the proportion and cumulative incidence at the end of follow-up of patients meeting each indicator and stratified results by age, sex, cohort entry, and chronic kidney disease stage.

RESULTS

Less than half of patients received follow-up tests after an initial abnormal kidney function result. Most patients with chronic kidney disease received regular monitoring of serum creatinine (91%), but urine albumin-to-creatinine monitoring was lower (70%). A total of 84% of patients age 66 and older did not receive a non-steroidal anti-inflammatory drug prescription of at least 2-week duration. Three quarters of patients age 66 and older were on an ACE inhibitor or ARB, and 96% did not receive an ACE inhibitor and ARB concurrently. Among patients 66 to 80 years of age with chronic kidney disease, 65% were on a statin. One quarter of patients age 66 and older who initiated an ACE inhibitor or ARB had their serum creatinine and potassium monitored within 7 to 30 days.

LIMITATIONS

This study was limited to people in Ontario with linked laboratory information.

CONCLUSIONS

There was generally strong performance across many of the quality of care indicators. Areas where more attention may be needed are laboratory testing to confirm initial abnormal kidney function test results and monitoring serum creatinine and potassium after initiating a new ACE inhibitor or ARB.

Systematic review and meta-analysis of renal replacement therapy modalities for acute kidney injury in the intensive care unit

PURPOSE

To compare clinical outcomes among critically ill adults with acute kidney injury (AKI) treated with continuous renal replacement therapy (CRRT), intermittent hemodialysis (IHD) or sustained low efficiency dialysis (SLED).

MATERIALS AND METHODS

We completed a systematic review and meta-analysis of studies published in 2015 or earlier using MEDLINE®, EMBASE®, Cochrane databases and grey literature. Eligible studies included randomized clinical trials (RCTs) or prospective cohort studies comparing outcomes of mortality, dialysis dependence or length of stay among critically ill adults receiving CRRT, IHD or SLED to treat AKI. Mortality and dialysis dependence from RCTs were pooled using meta-analytic techniques. Length of stay from RCTs and results from prospective cohort studies were described qualitatively.

RESULTS

Twenty-one studies were eligible. RRT modality was not associated with in-hospital mortality (CRRT vs IHD: RR 1.00 [95% CI, 0.92-1.09], CRRT vs SLED: RR 1.23 [95% CI, 1.00-1.51]) or dialysis dependence (CRRT vs IHD: RR 0.90 [95% CI, 0.59-1.38], CRRT vs SLED: RR 1.15 [95% CI, 0.67-1.99]).

CONCLUSIONS

We did not find a definitive advantage for any RRT modality on short-term patient or kidney survival. Well-designed, adequately-powered trials are needed to better define the role of RRT modalities for treatment of critically ill patients with AKI.

Kidney Disease Among Registered Métis Citizens of Ontario: A Population-Based Cohort Study

Background:

Indigenous peoples in Canada have higher rates of kidney disease than non-Indigenous Canadians. However, little is known about the risk of kidney disease specifically in the Métis population in Canada.

Objective:

To compare the prevalence of chronic kidney disease and incidence of acute kidney injury and end-stage kidney disease among registered Métis citizens in Ontario and a matched sample from the general Ontario population.

Design:

Population-based, retrospective cohort study using data from the Métis Nation of Ontario’s Citizenship Registry and administrative databases.

Setting:

Ontario, Canada; 2003-2013.

Patients:

Ontario residents ≥18 years.

Measurements:

Prevalence of chronic kidney disease and incidence of acute kidney injury and end-stage kidney disease. Secondary outcomes among patients hospitalized with acute kidney injury included non-recovery of kidney function and mortality within 1 year of discharge.

Methods:

Database codes and laboratory values were used to determine study outcomes. Métis citizens were matched (1:4) to Ontario residents on age, sex, and area of residence. The analysis included 12 229 registered Métis citizens and 48 916 adults from the general population.

Results:

We found the prevalence of chronic kidney disease was slightly higher among Métis citizens compared with the general population (3.1% vs 2.6%, P = 0.002). The incidence of acute kidney injury was 1.2 per 1000 person-years in both Métis citizens and the general population (P = 0.54). Of those hospitalized with acute kidney injury, outcomes were similar among Métis citizens and the general population except 1-year mortality, which was higher for Métis citizens (24.5% vs 15.3%, P = 0.03). The incidence of end-stage kidney disease did not differ between groups (<3.0 per 10 000 person-years, P = 0.73).

Limitations:

The Métis Nation of Ontario Citizenship Registry only captures about 20% of Métis people in Ontario. Administrative health care codes used to identify kidney disease are highly specific but have low sensitivity.

Conclusions:

Rates of kidney disease were similar or slightly higher for Métis citizens in Ontario compared with the matched general population.

Improving Care for Patients With or at Risk for Chronic Kidney Disease Using Electronic Medical Record Interventions: A Pragmatic Cluster-Randomized Trial Protocol

BACKGROUND

Many patients with or at risk for chronic kidney disease (CKD) in the primary care setting are not receiving recommended care.

OBJECTIVE

The objective of this study is to determine whether a multifaceted, low-cost intervention compared with usual care improves the care of patients with or at risk for CKD in the primary care setting.

DESIGN

A pragmatic cluster-randomized trial, with an embedded qualitative process evaluation, will be conducted.

SETTING

The study population comes from the Electronic Medical Record Administrative data Linked Database®, which includes clinical data for more than 140 000 rostered adults cared for by 194 family physicians in 34 clinics across Ontario, Canada. The 34 primary care clinics will be randomized to the intervention or control group.

INTERVENTION

The intervention group will receive resources from the "CKD toolkit" to help improve care including practice audit and feedback, printed educational materials for physicians and patients, electronic decision support and reminders, and implementation support.

MEASUREMENTS

Patients with or at risk for CKD within participating clinics will be identified using laboratory data in the electronic medical records. Outcomes will be assessed after dissemination of the CKD tools and after 2 rounds of feedback on performance on quality indicators have been sent to the physicians using information from the electronic medical records. The primary outcome is the proportion of patients aged 50 to 80 years with nondialysis-dependent CKD who are on a statin. Secondary outcomes include process of care measures such as screening tests, CKD recognition, monitoring tests, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker prescriptions, blood pressure targets met, and nephrologist referral. Hierarchical analytic modeling will be performed to account for clustering. Semistructured interviews will be conducted with a random purposeful sample of physicians in the intervention group to understand why the intervention achieved the observed effects.

CONCLUSIONS

If our intervention improves care, then the CKD toolkit can be adapted and scaled for use in other primary care clinics which use electronic medical records.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02274298.

30-Day Readmissions After an Acute Kidney Injury Hospitalization

BACKGROUND

The risk of hospital readmission in acute kidney injury survivors is not well understood. We estimated the proportion of acute kidney injury patients who were rehospitalized within 30 days and identified characteristics associated with hospital readmission.

METHODS

We conducted a population-based study of patients who survived a hospitalization complicated by acute kidney injury from 2003-2013 in Ontario, Canada. The primary outcome was 30-day hospital readmission. We used a propensity score model to match patients with and without acute kidney injury, and a Cox proportional hazards model with death as a competing risk to identify predictors of 30-day readmission.

RESULTS

We identified 156,690 patients who were discharged from 197 hospitals after an episode of acute kidney injury. In the subsequent 30 days, 27,457 (18%) patients were readmitted; 15,988 (10%) visited the emergency department and 7480 (5%) died. We successfully matched 111,778 patients with acute kidney injury 1:1 to patients without acute kidney injury. The likelihood of 30-day readmission was higher in acute kidney injury patients than those without acute kidney injury (hazard ratio [HR] 1.53; 95% confidence interval [CI], 1.50-1.57). Factors most strongly associated with 30-day rehospitalization were the number of hospitalizations in the preceding year (adjusted HR 1.45 for ≥2 hospitalizations; 95% CI, 1.40-1.51) and receipt of inpatient chemotherapy (adjusted HR 1.44; 95% CI, 1.32-1.58).

CONCLUSIONS

One in 5 patients who survive a hospitalization complicated by acute kidney injury is readmitted in the next 30 days. Better strategies are needed to identify and care for acute kidney injury survivors in the community.

Patterns and Predictors of Screening for Breast and Cervical Cancer in Women with CKD

BACKGROUND AND OBJECTIVES

Breast and cervical cancers are prevalent in women with CKD, but it is uncertain how often screening for these cancers should be undertaken given concerns that the benefits of screening may be fewer and the harms greater in women with CKD than in the general population. We examined patterns of breast and cervical cancer screening in women on the basis of CKD stage and age and assessed predictors of screening.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted two population-based cohort studies (breast and cervical cancer screening) from 2002 to 2013 using linked administrative health care data from Ontario, Canada. A total of 141,326 and 324,548 women were included in the breast and cervical cancer screening cohorts, respectively.

RESULTS

The 2-year cumulative incidences were 61% among women without CKD, 54% for those with CKD stages 3a and 3b, 37% for those with CKD stages 4 and 5, and 26% for women on dialysis. Similar patterns were observed for the 3-year cumulative incidences of cervical cancer screening. The associations of breast and cervical cancer screening with CKD were modified by age and CKD stage, where lower incidence of screening in women with advanced CKD compared with no CKD was most pronounced in older age groups (P<0.001). Older age, higher comorbidity burden, and lower-income groups were associated with a lower rate of screening.

CONCLUSIONS

Most women with advanced CKD do not receive breast or cervical cancer screening. A better understanding of patient and health professional preferences toward cancer screening in CKD is needed along with the outcomes of such screening.

Dialysis Modality and Readmission Following Hospital Discharge: A Population-Based Cohort Study

BACKGROUND

Readmissions following hospital discharge among maintenance dialysis patients are common, potentially modifiable, and costly. Compared with patients receiving in-center hemodialysis (HD), patients receiving peritoneal dialysis (PD) have fewer routine dialysis clinic encounters and as a result may be more susceptible to a hospital readmission following discharge.

STUDY DESIGN

Population-based retrospective-cohort observational study.

SETTINGS & PARTICIPANTS

Patients treated with maintenance dialysis who were discharged following an acute-care hospitalization during January 1, 2003, to December 31, 2013, across 164 acute-care hospitals in Ontario, Canada. For those with multiple hospitalizations, we randomly selected a single hospitalization as the index hospitalization.

PREDICTOR

Dialysis modality PD or in-center HD. Propensity scores were used to match each patient on PD therapy to 2 patients on in-center HD therapy to ensure that baseline indicators of health were similar between the 2 groups.

OUTCOME

All-cause 30-day readmission following the index hospital discharge.

RESULTS

28,026 dialysis patients were included in the study. 4,013 PD patients were matched to 8,026 in-center HD patients. Among the matched cohort, 30-day readmission rates were 7.1 (95% CI, 6.6-7.6) per 1,000 person-days for patients on PD therapy and 6.0 (95% CI, 5.7-6.3) per 1,000 person-days for patients on in-center HD therapy. The risk for a 30-day readmission among patients on PD therapy was higher compared with those on in-center HD therapy (adjusted HR, 1.19; 95% CI, 1.08-1.31). The primary results were consistent across several key prespecified subgroups.

LIMITATIONS

Lack of information for the frequency of nephrology physician encounters following discharge from the hospital in both the PD and in-center HD cohorts. Limited validation of International Classification of Diseases, Tenth Revision codes.

CONCLUSIONS

The risk for 30-day readmission is higher for patients on home-based PD compared to in-center HD therapy. Interventions to improve transitions in care between the inpatient and outpatient settings are needed, particularly for patients on PD therapy.

Positive Predictive Values of International Classification of Diseases, 10th Revision Coding Algorithms to Identify Patients With Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

International Classification of Diseases, 10th Revision codes (ICD-10) for autosomal dominant polycystic kidney disease (ADPKD) is used within several administrative health care databases. It is unknown whether these codes identify patients who meet strict clinical criteria for ADPKD.

OBJECTIVE

The objective of this study is (1) to determine whether different ICD-10 coding algorithms identify adult patients who meet strict clinical criteria for ADPKD as assessed through medical chart review and (2) to assess the number of patients identified with different ADPKD coding algorithms in Ontario.

DESIGN

Validation study of health care database codes, and prevalence.

SETTING

Ontario, Canada.

PATIENTS

For the chart review, 201 adult patients with hospital encounters between April 1, 2002, and March 31, 2014, assigned either ICD-10 codes Q61.2 or Q61.3.

MEASUREMENTS

This study measured positive predictive value of the ICD-10 coding algorithms and the number of Ontarians identified with different coding algorithms.

METHODS

We manually reviewed a random sample of medical charts in London, Ontario, Canada, and determined whether or not ADPKD was present according to strict clinical criteria.

RESULTS

The presence of either ICD-10 code Q61.2 or Q61.3 in a hospital encounter had a positive predictive value of 85% (95% confidence interval [CI], 79%-89%) and identified 2981 Ontarians (0.02% of the Ontario adult population). The presence of ICD-10 code Q61.2 in a hospital encounter had a positive predictive value of 97% (95% CI, 86%-100%) and identified 394 adults in Ontario (0.003% of the Ontario adult population).

LIMITATIONS

(1) We could not calculate other measures of validity; (2) the coding algorithms do not identify patients without hospital encounters; and (3) coding practices may differ between hospitals.

CONCLUSIONS

Most patients with ICD-10 code Q61.2 or Q61.3 assigned during their hospital encounters have ADPKD according to the clinical criteria. These codes can be used to assemble cohorts of adult patients with ADPKD and hospital encounters.

Hospitalization Rates for Patients on Assisted Peritoneal Dialysis Compared with In-Center Hemodialysis

BACKGROUND AND OBJECTIVES

Assisted peritoneal dialysis is a treatment option for individuals with barriers to self-care who wish to receive home dialysis, but previous research suggests that this treatment modality is associated with a higher rate of hospitalization. The objective of our study was to determine whether assisted peritoneal dialysis has a different rate of hospital days compared to in-center hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a multicenter, retrospective cohort study by linking a quality assurance dataset to administrative health data in Ontario, Canada. Subjects were accrued between January 1, 2004 and July 9, 2013. Individuals were grouped into assisted peritoneal dialysis (family or home care assisted) or in-center hemodialysis on the basis of their first outpatient dialysis modality. Inverse probability of treatment weighting using a propensity score was used to create a sample in which the baseline covariates were well balanced.

RESULTS

The study included 872 patients in the in-center hemodialysis group and 203 patients in the assisted peritoneal dialysis group. Using an intention to treat approach, patients on assisted peritoneal dialysis had a similar hospitalization rate of 11.1 d/yr (95% confidence interval, 9.4 to 13.0) compared with 12.9 d/yr (95% confidence interval, 10.3 to 16.1) in the hemodialysis group (P=0.19). Patients on assisted peritoneal dialysis were more likely to be hospitalized for dialysis-related reasons (admitted for 2.4 d/yr [95% confidence interval, 1.8 to 3.2] compared with 1.6 d/yr [95% confidence interval, 1.1 to 2.3] in the hemodialysis group; P=0.04). This difference was partly explained by more hospital days because of peritonitis. Modality switching was associated with high rates of hospital days per year.

CONCLUSIONS

Assisted peritoneal dialysis was associated with similar rates of all-cause hospitalization compared with in-center hemodialysis. Patients on assisted peritoneal dialysis who experienced peritonitis and technique failure had high rates of hospitalization.

Risk of Ventricular Arrhythmia with Citalopram and Escitalopram: A Population-Based Study

Background

The risk of ventricular arrhythmia with citalopram and escitalopram is controversial. In this study we investigated the association between these two drugs and the risk of ventricular arrhythmia.

Methods

We conducted a population-based retrospective cohort study of older adults (mean age 76 years) from 2002 to 2012 in Ontario, Canada, newly prescribed citalopram (n = 137 701) or escitalopram (n = 38 436), compared to those prescribed referent antidepressants sertraline or paroxetine (n = 96 620). After inverse probability of treatment weighting using a propensity score, the baseline characteristics of the comparison groups were similar. The primary outcome was a hospital encounter with ventricular arrhythmia within 90 days of a new prescription, assessed using hospital diagnostic codes. The secondary outcome was all-cause mortality within 90 days.

Results

Citalopram was associated with a higher risk of a hospital encounter with ventricular arrhythmia compared with referent antidepressants (0.06% vs. 0.04%, relative risk [RR] 1.53, 95% confidence intervals [CI]1.03 to 2.29), and a higher risk of mortality (3.49% vs. 3.12%, RR 1.12, 95% CI 1.06 to 1.18). Escitalopram was not associated with a higher risk of ventricular arrhythmia compared with the referent antidepressants (0.03% vs. 0.04%, RR 0.84, 95% CI 0.42 to 1.68), but was associated with a higher risk of mortality (2.86% vs. 2.63%, RR 1.09, 95% CI 1.01 to 1.18).

Conclusion

Among older adults, initiation of citalopram compared to two referent antidepressants was associated with a small but statistically significant increase in the 90-day risk of a hospital encounter for ventricular arrhythmia.

Teaching surgery takes time: the impact of surgical education on time in the operating room

BACKGROUND

It is generally accepted that surgical training is associated with increased surgical duration. The purpose of this study was to determine the magnitude of this increase for common surgical procedures by comparing surgery duration in teaching and nonteaching hospitals.

METHODS

This retrospective population-based cohort study included all adult residents of Ontario, Canada, who underwent 1 of 14 surgical procedures between 2002 and 2012. We used several linked administrative databases to identify the study cohort in addition to patient-, surgeon- and procedure-related variables. We determined surgery duration using anesthesiology billing records. Negative binomial regression was used to model the association between teaching versus nonteaching hospital status and surgery duration.

RESULTS

Of the 713 573 surgical cases included in this study, 20.8% were performed in a teaching hospital. For each procedure, the mean surgery duration was significantly longer for teaching hospitals, with differences ranging from 5 to 62 minutes across individual procedures in unadjusted analyses (all p < 0.001). In regression analysis, procedures performed in teaching hospitals were associated with an overall 22% (95% confidence interval 20%-24%) increase in surgery duration, adjusting for patient-, surgeon- and procedure-related variables as well as the clustering of patients within surgeons and hospitals.

CONCLUSION

Our results show that a wide range of surgical procedures require significantly more time to perform in teaching than nonteaching hospitals. Given the magnitude of this difference, the impact of surgical training on health care costs and clinical outcomes should be a priority for future studies.