Reduced kidney function confers a higher risk of acute kidney injury at the time of an inciting event, such as sepsis. Whether the same is true in those with reduced renal mass from living kidney donation is unknown.
We conducted a population-based matched cohort study of all living kidney donors in the province of Ontario, Canada who underwent donor nephrectomy from 1992 to 2009. We manually reviewed the medical records of these living kidney donors and linked this information to provincial health care databases. Non-donors were selected from the healthiest segment of the general population.
There were 2027 donors and 20 270 matched non-donors. The median age was 43 years (interquartile range 34-50) and individuals were followed for a median of 6.6 years (maximum 17.7 years). The primary outcome was acute dialysis during any hospital stay. Reasons for hospitalization included infectious diseases, cardiovascular diseases and hematological malignancies. Only one donor received acute dialysis in follow-up (6.5 events per 100 000 person-years), a rate which was statistically no different than 14 non-donors (9.4 events per 100 000 person-years).
These results are reassuring for the practice of living kidney donation. Longer follow-up of this and other donor cohorts will provide more precise estimates about this risk.
Knowledge of the long-term prognosis of patients with diarrhea-associated hemolytic uremic syndrome (HUS) is important for patient counseling and follow-up. Estimates in the literature are highly variable, and previous studies did not use a healthy control group to establish outcomes attributable to HUS.
Prospective cohort study.
19 children who recovered from HUS after contamination of their municipal water supply by Escherichia coli O157:H7.
Outcomes of children who recovered from HUS were compared with a control group of 64 children who were healthy at the time of the outbreak. Both groups were similar in their demographics and follow-up testing.
Proteinuria, blood pressure, glomerular filtration rate (GFR) estimated by using serum creatinine or cystatin C level, and biochemical measures 5 years after the outbreak.
More children who recovered from HUS showed microalbuminuria than controls (20% versus 3%; relative risk, 6.0; 95% confidence interval, 1.1 to 32.8). There were no differences between groups in blood pressure or GFR when estimated by using serum creatinine level. GFR estimated by using cystatin C level was lower after HUS compared with controls (100 versus 110 mL/min/1.73 m(2); P = 0.02), but no child had a GFR less than 80 mL/min/1.73 m(2). Other results, including fasting glucose, albumin, and C-reactive protein levels, did not differ between groups.
Although the homogenous nature of this outbreak is a strength, long-term results may generalize less well to patients with other strains of toxigenic E coli or in other settings.
The prognosis of patients with HUS in this cohort was better than in other studies. Ongoing follow-up will clarify the clinical relevance of microalbuminuria and mild decreases in GFR 5 years after HUS recovery.
Acute bacterial gastroenteritis is associated with subsequent post-infectious irritable bowel syndrome (PI-IBS) in adults. Less is known about this relationship in children. In May 2000, contamination of municipal water by Escherichia coli 0157:H7 and Campylobacter species caused a large outbreak of acute gastroenteritis in Walkerton, Ontario. We assessed this association among a cohort of children enrolled in the Walkerton Health Study (WHS).
WHS participants who were under age 16 at the time of the outbreak but who reached age 16 during the 8-year study follow-up were eligible for the pediatric PI-IBS study cohort. Eligibility also required no diagnosis of IBS or inflammatory bowel disease before the outbreak and permanent residency in the Walkerton postal code at the time of the outbreak. Validated criteria were used to classify subjects as having had no gastroenteritis (unexposed controls), self-reported gastroenteritis, or clinically suspected gastroenteritis during the outbreak. From 2002 to 2008, standardized biennial interviews used a modified Bowel Disease Questionnaire to diagnose IBS by Rome I criteria. Risk factors for IBS were identified by logistic regression.
In all, 467 subjects were eligible for the pediatric PI-IBS study cohort (47.1% female; mean age 11.6+/-2.44 years at the time of the outbreak). Of these, 305 were exposed to GE (130 clinically suspected and 175 self-reported) and 162 were unexposed controls. The cumulative incidence of IBS was significantly increased among exposed subjects vs. controls (10.5% vs. 2.5%; odds ratio 4.6, 95% confidence interval (1.6, 13.3)). In an unadjusted risk factor analysis, IBS was associated with a shorter time interval from exposure to assessment of IBS symptoms, female gender, diarrheal illness lasting more than 7 days, weight loss >10 lb, and antibiotic use during the outbreak. In adjusted analyses, both female gender and time interval to assessment of IBS symptoms remained independent predictors of PI-IBS.
Acute bacterial gastroenteritis is associated with subsequent IBS in children as in adults. Risk factors for PI-IBS in children are similar to those identified among adults. Confirmation of these findings in similar cohorts is needed.
1Division of Nephrology, St. Michael's Hospital and University of Toronto, Toronto, ON, Canada. 2Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada. 3Institute for Clinical Evaluative Sciences, Toronto, ON, Canada. 4Department of Critical Care Medicine and Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada. 5Interdepartmental Division of Critical Care, University of Toronto, Toronto, ON, Canada. 6Division of Critical Care Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada. 7Departments of Critical Care and Medicine, St. Michael's Hospital, Toronto, ON, Canada. 8Division of Nephrology, London Health Sciences Centre, London, ON, Canada. 9Division of General Internal Medicine, St. Michael's Hospital, Toronto, ON, Canada.
Among critically ill patients with acute kidney injury, the impact of renal replacement therapy modality on long-term kidney function is unknown. Compared with conventional intermittent hemodialysis, continuous renal replacement therapy may promote kidney recovery by conferring greater hemodynamic stability; yet continuous renal replacement therapy may not enhance patient survival and is resource intense. Our objective was to determine whether continuous renal replacement therapy was associated with a lower risk of chronic dialysis as compared with intermittent hemodialysis, among survivors of acute kidney injury.
Retrospective cohort study.
Linked population-wide administrative databases in Ontario, Canada.
Critically ill adults who initiated dialysis for acute kidney injury between July 1996 and December 2009. In the primary analysis, we considered those who survived to at least 90 days after renal replacement therapy initiation.
Initial receipt of continuous renal replacement therapy versus intermittent hemodialysis.
Continuous renal replacement therapy recipients were matched 1:1 to intermittent hemodialysis recipients based on a history of chronic kidney disease, receipt of mechanical ventilation, and a propensity score for the likelihood of receiving continuous renal replacement therapy. Cox proportional hazards were used to evaluate the relationship between initial renal replacement therapy modality and the primary outcome of chronic dialysis, defined as the need for dialysis for a consecutive period of 90 days. We identified 2,315 continuous renal replacement therapy recipients of whom 2,004 (87%) were successfully matched to 2,004 intermittent hemodialysis recipients. Participants were followed over a median duration of 3 years. The risk of chronic dialysis was significantly lower among patients who initially received continuous renal replacement therapy versus intermittent hemodialysis (hazard ratio, 0.75; 95% CI, 0.65-0.87). This relation was more prominent among those with preexisting chronic kidney disease (p value for interaction term = 0.065) and heart failure (p value for interaction term = 0.035).
Compared with intermittent hemodialysis, initiation of continuous renal replacement therapy in critically ill adults with acute kidney injury is associated with a lower likelihood of chronic dialysis.
Comment In: Crit Care Med. 2014 Jul;42(7):e540-124933070
Comment In: Crit Care Med. 2014 Apr;42(4):990-124633101
Comment In: Crit Care Med. 2014 Jul;42(7):e54124933071
In living kidney donation, transplant professionals consider the rights of a living kidney donor and recipient to keep their personal health information confidential and the need to disclose this information to the other for informed consent. In incompatible kidney exchange, personal health information from multiple living donors and recipients may affect decision making and outcomes.
We conducted a survey to understand and compare the preferences of potential donors (n = 43), potential recipients (n = 73), and health professionals (n = 41) toward sharing personal health information (in total 157 individuals).
When considering traditional live-donor transplantation, donors and recipients generally agreed that a recipient's health information should be shared with the donor (86 and 80%, respectively) and that a donor's information should be shared with the recipient (97 and 89%, respectively). When considering incompatible kidney exchange, donors and recipients generally agreed that a recipient's information should be shared with all donors and recipients involved in the transplant (85 and 85%, respectively) and that a donor's information should also be shared with all involved (95 and 90%, respectively). These results were contrary to attitudes expressed by transplant professionals, who frequently disagreed about whether such information should be shared.
Future policies and practice could facilitate greater sharing of personal health information in living kidney donation. This requires a consideration of which information is relevant, how to put it in context, and a plan to obtain consent from all concerned.
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Beta-blockers may be cardioprotective in patients receiving chronic dialysis. We examined cardiovascular outcomes among incident dialysis patients receiving beta-blocker therapy.
We conducted a retrospective cohort study employing linked healthcare databases in Ontario, Canada. We studied all consecutive chronic dialysis patients aged=66 years who initiated dialysis between 1 July 1991 and 31 July 2007. Patients were divided into three groups according to new medication use after the initiation of chronic dialysis. The three groups were patients initiated on beta-blockers, calcium channel blockers and statins only. Patients in the beta-blocker and calcium channel blocker groups could also be concurrently receiving a statin. The primary outcome was time to a composite endpoint of death, myocardial infarction, stroke or coronary revascularization.
There were a total of 1836 patients (504 beta-blocker, 570 calcium channel blocker and 762 statin-only users). Compared to statin-only use, beta-blocker use was not associated with improved cardiovascular outcomes [adjusted hazard ratio (aHR) 1.07, 95% confidence interval (CI) 0.92-1.23]. As expected, calcium channel blocker use was also not associated with improved cardiovascular outcomes (aHR 0.91, 95% CI 0.79-1.06). Among all subgroup analyses by beta-blocker attributes, only high-dose beta-blocker therapy was associated with better cardiovascular outcomes as compared to low-dose beta-blockers (aHR 0.50, 95% CI 0.29-0.88).
We observed no beneficial effect of beta-blocker use among patients receiving chronic dialysis relative to our comparator groups. Given current uncertainty around the cardioprotective benefits of beta-blockers in patients receiving dialysis, a large randomized clinical trial is warranted.
Escherichia coli O157:H7 is one cause of acute bacterial gastroenteritis, which can be devastating in outbreak situations. We studied the risk of cardiovascular disease following such an outbreak in Walkerton, Ontario, in May 2000.
In this community-based cohort study, we linked data from the Walkerton Health Study (2002-2008) to Ontario's large healthcare databases. We included 4 groups of adults: 3 groups of Walkerton participants (153 with severe gastroenteritis, 414 with mild gastroenteritis, 331 with no gastroenteritis) and a group of 11 263 residents from the surrounding communities that were unaffected by the outbreak. The primary outcome was a composite of death or first major cardiovascular event (admission to hospital for acute myocardial infarction, stroke or congestive heart failure, or evidence of associated procedures). The secondary outcome was first major cardiovascular event censored for death. Adults were followed for an average of 7.4 years.
During the study period, 1174 adults (9.7%) died or experienced a major cardiovascular event. Compared with residents of the surrounding communities, the risk of death or cardiovascular event was not elevated among Walkerton participants with severe or mild gastroenteritis (hazard ratio [HR] for severe gastroenteritis 0.74, 95% confidence interval [CI] 0.38-1.43, mild gastroenteritis HR 0.64, 95% CI 0.42-0.98). Compared with Walkerton participants who had no gastroenteritis, risk of death or cardiovascular event was not elevated among participants with severe or mild gastroenteritis.
There was no increase in the risk of cardiovascular disease in the decade following acute infection during a major E. coli O157:H7 outbreak.
Knowledge of any harm associated with living kidney donation guides informed consent and living donor follow-up. Risk estimates in the literature are variable, and most studies did not use a healthy control group to assess outcomes attributable to donation.
We observed a retrospective cohort using health administrative data for donations which occurred in Ontario, Canada between the years 1993 and 2005. There were a total of 1278 living donors and 6359 healthy adults who acted as a control group. Individuals were followed for a mean of 6.2 years (range, 1-13 years) after donation. The primary outcome was a composite of time to death or first cardiovascular event (myocardial infarction, stroke, angioplasty, and bypass surgery). The secondary outcome was time to a diagnosis of hypertension.
There was no significant difference in death or cardiovascular events between donors and controls (1.3% vs. 1.7%; hazard ratio 0.7, 95% confidence interval 0.4-1.2). Donors were more frequently diagnosed with hypertension than controls (16.3% vs. 11.9%, hazard ratio 1.4, 95% confidence interval 1.2-1.7) but were also seen more often by their primary care physicians (median [interquartile range] 3.6 [1.9-6.1] vs. 2.6 [1.4-4.3] visits per person year, P
To determine whether people who donate a kidney have an increased risk of cardiovascular disease.
Retrospective population based matched cohort study.
All people who were carefully selected to become a living kidney donor in the province of Ontario, Canada, between 1992 and 2009. The information in donor charts was manually reviewed and linked to provincial healthcare databases. Matched non-donors were selected from the healthiest segment of the general population. A total of 2028 donors and 20,280 matched non-donors were followed for a median of 6.5 years (maximum 17.7 years). Median age was 43 at the time of donation (interquartile range 34-50) and 50 at the time of follow-up (42-58).
The primary outcome was a composite of time to death or first major cardiovascular event. The secondary outcome was time to first major cardiovascular event censored for death.
The risk of the primary outcome of death and major cardiovascular events was lower in donors than in non-donors (2.8 v 4.1 events per 1000 person years; hazard ratio 0.66, 95% confidence interval 0.48 to 0.90). The risk of major cardiovascular events censored for death was no different in donors than in non-donors (1.7 v 2.0 events per 1000 person years; 0.85, 0.57 to 1.27). Results were similar in all sensitivity analyses. Older age and lower income were associated with a higher risk of death and major cardiovascular events in both donors and non-donors when each group was analysed separately.
The risk of major cardiovascular events in donors is no higher in the first decade after kidney donation compared with a similarly healthy segment of the general population. While we will continue to follow people in this study, these interim results add to the evidence base supporting the safety of the practice among carefully selected donors.
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Patients choosing between hemodialysis (HD) and peritoneal dialysis (PD) should be well informed of the risks and benefits of each modality. Invasive access interventions are important outcomes because frequent interventions lower patient's quality of life and consume limited resources. The objective of this study was to compare the risk of access interventions between the two modalities.
Three hundred and sixty-nine incident chronic dialysis patients were prospectively enrolled at four Canadian centers that were eligible for both modalities, received at least 4 months of pre-dialysis care and started dialysis electively as an outpatient. Two hundred and twenty-four (61%) chose PD and 145 (39%) chose HD. Patients were followed for an average of 1.3 years (range 0.07-3.6 years).
In the PD group, there were fewer access interventions (2.5 versus 3.1 interventions per patient, adjusted odds ratio of 0.79 for PD versus HD, P = 0.005) and a lower intervention rate (2.3 versus 1.9 per patient-year, adjusted rate ratio of 0.81 for PD versus HD, P = 0.04). PD catheters were less likely to experience primary failure (4.6 versus 32%, P