Andrea Soo

Survival in pediatric dialysis and transplant patients.

BACKGROUND AND OBJECTIVES Long-term follow-up data are few in children with ESRD. We sought to describe long-term survival, assess risk factors for death, and compare survival between two time periods in pediatric ESRD patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We used a population-based retrospective cohort utilizing data from a national organ failure registry and from Canadas universal healthcare system. We included 843 children (ages, 0 to 18) initiating renal replacement therapy from 1992 to 2007 and followed them until death or date of last contact (median follow-up, 6.8 years; interquartile range, 3.0 to 10.6). We assessed risk factors for death and examined cause-specific mortality. RESULTS During 5991 patient-years of follow-up, 107 (12.7%) patients died. Unadjusted cumulative survival for the cohort was: 91.7% (95% CI, 89.8 to 93.7%) at 5 years and 85.8% (95% CI, 82.8 to 88.8%) at 10 years. Among patients commencing dialysis, overall adjusted survival was poorest among those who started dialysis at age <1 year. No secular trends in survival were noted for either dialysis or transplant patients. The proportion of incident patients receiving pre-emptive transplantation increased over time. Pre-emptively transplanted patients did not demonstrate superior adjusted survival compared with those who spent >2 years on dialysis before transplant (hazard ratio, 1.53; 95% CI, 0.63 to 3.67). CONCLUSIONS No significant improvements in survival were observed among ESRD patients over the study period. Time with transplant function had the strongest association with survival. Pre-emptive transplantation was not associated with improved survival in adjusted models.

Graft failure and adaptation period to adult healthcare centers in pediatric renal transplant patients.

Background. Transfer from pediatric to adult care may require a period of adaptation to the new healthcare environment. We sought to determine whether this adaptation period was associated with an increased risk of graft failure. Methods. Children (age, 0–18 years) recorded in the Canadian Organ Replacement Register who received a first kidney transplant in a pediatric health center between 1992 and 2007, and who had more than or equal to 3 months of graft function, were followed up until death, loss to follow-up, or December 31, 2007. Cox proportional hazards models were used to estimate the excess risk associated with a period of adaptation to adult-oriented care, defined as the interval 0.5 years before to 2.5 years after the first recorded adult care visit. Models were adjusted for age, gender, donor source, and ethnicity. Results. Of the 413 patients evaluated, 149 were transferred to adult care during study period. In total, 78 (18.9%) patients experienced graft failure—23 during the adaptation period. Compared with the period before adaptation, the adjusted hazard ratio for graft loss within the adaptation period was 2.24 (95% confidence interval [CI]: 1.19–4.20). The adjusted graft failure rate was 2.26 (1.04–4.93) times higher after 18 years of age than between 0 and 13 years. Aboriginal ethnicity and deceased donor source were also associated with a significantly higher risk of graft failure. Conclusions. The period of adaptation to adult-oriented care is associated with a high risk of graft failure in pediatric renal transplant patients.

Predictors of Nursing Home Placement from Assisted Living Settings in Canada.

Cette étude visait à évaluer l’incidence de placement dans un établissement de soins de longue durée (SLD) et d’identifier les facteurs prédictifs de placement résidentiel et d’installation parmi résidents âgés dans établissements aidant à la vie autonome en Alberta, au Canada. 1,086 résidents de 59 installations en Alberta ont été inclus. Infirmières de recherche ont effectué des évaluations de résidents interRAI-AL et ont interrogé les aidants familiaux et les administrateurs. Les prédicteurs de placement ont été identifiés avec des modèles de risques proportionnels de Cox multivariés. L’incidence cumulative SLD de l’admission était de 18,3 pour cent en 12 mois. Le risque de placement a augmenté significativement pour les résidents âgés et ceux avec des relations sociales médiocres, peu d’implication dans les activités, la dépreciation cognitive et/ou fonctionnelle, l’instabilité de la santé, une histoire des chutes et des hospitalisations récentes/visites à l’urgence, et l’incontinence urinaire sévère. Une diminution du risque de placement a été montré pour les résidents de grandes établissements avec une infirmière autorisée et/ou une infirmière auxiliaire autorisée disponible 24 heures par jour et un médecin de premier recours affilié. Nos résultats font ressortir les domaines cliniques et politiques ou des interventions ciblées peuvent retarder les admissions SLD.

Avoidable Hospitalizations in Youth With Kidney Failure After Transfer to or With Only Adult Care

OBJECTIVE: Hospital admissions for ambulatory care–sensitive conditions (also called avoidable hospitalizations) are a measure of quality and access to outpatient care. We determined if young patients with end-stage renal disease (ESRD) are at increased risk of avoidable hospitalizations. METHODS: A national organ failure registry was used to identify patients with ESRD onset at <22 years of age between April 1, 2001, and March 31, 2010, who had received care in an adult care facility after age 15 years. The cohort was linked to the national hospitalizations database to identify avoidable hospitalizations relevant for young patients with ESRD. Patients were followed up until death, loss to follow-up, or study end. Two groups were studied: (1) patients transferred from pediatric to adult care; and (2) patients receiving ESRD care exclusively in adult centers. We determined the association between overall and avoidable hospitalization rates and both age and transfer status by using Poisson regression models. RESULTS: Our cohort included 349 patients. Among the 92 (26.4%) patients transferred to adult care during the study period, avoidable hospitalization rates were highest during the period 3 to <4 years after transfer (rate ratio: 3.19 [95% confidence interval: 1.42–7.18]) compared with the last year in pediatric care. Among the 257 (73.6%) patients who received ESRD care exclusively in adult centers, avoidable hospitalization rates increased with age. CONCLUSIONS: Among those who were transferred to adult care, avoidable hospitalization rates increased after transfer. Avoidable hospitalization rates increased with age in ESRD patients who received care in adult centers. Young patients with ESRD are at increased risk of avoidable hospitalizations.

Classification with discrete and continuous variables via general mixed-data models

We study the problem of classifying an individual into one of several populations based on mixed nominal, continuous, and ordinal data. Specifically, we obtain a classification procedure as an extension to the so-called location linear discriminant function, by specifying a general mixed-data model for the joint distribution of the mixed discrete and continuous variables. We outline methods for estimating misclassification error rates. Results of simulations of the performance of proposed classification rules in various settings vis-à-vis a robust mixed-data discrimination method are reported as well. We give an example utilizing data on croup in children.

Association between residence location and likelihood of transplantation among pediatric dialysis patients.

Samuel SM, Hemmelgarn B, Nettel‐Aguirre A, Foster B, Soo A, Alexander RT, Tonelli M, Pediatric Renal Outcomes Canada Group. Association between residence location and likelihood of transplantation among pediatric dialysis patients.

Quality of care for First Nations and non-First Nations People with diabetes.

BACKGROUND AND OBJECTIVES Compared with non-First Nations, First Nations People with diabetes experience higher rates of kidney failure and death, which may be related to disparities in care. This study examined First Nations and non-First Nations People with diabetes for differences in quality indicators and their association with kidney failure and death. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Adults with diabetes and an outpatient creatinine in Alberta from 2005 to 2008 were identified. Logistic regression was used to determine the likelihood of process of care indicators (measurement of urine albumin/creatinine ratio [ACR], LDL, and hemoglobin A1C [A1C]) and surrogate outcome indicators (achievement of LDL and A1C targets). Cox regression was used to determine the association between lack of achievement of indicator targets and each of kidney failure and death. RESULTS This study identified 140,709 non-First Nations and 6574 First Nations People with diabetes. There was a significant interaction between First Nations status and CKD for the outcomes (P<0.01); therefore, results are stratified by CKD. Among participants without CKD, First Nations People were less likely to receive process of care indicators and achieve target A1C compared with non-First Nations People. For those with CKD, First Nations People were as likely to receive these indicators (other than LDL) and achieve LDL and A1C targets. Lack of LDL and A1C assessment and achievement of targets were associated with increased risk of kidney failure and death similarly for both groups. CONCLUSIONS Compared with non-First Nations, First Nations People with diabetes but without CKD experience disparities in assessment of quality indicators and achievement of A1C target.

Dialysis and transplantation among Aboriginal children with kidney failure

Background: Relatively little is known about the management and outcomes of Aboriginal children with renal failure in Canada. We evaluated differences in dialysis modality, time spent on dialysis, rates of kidney transplantation, and patient and allograft survival between Aboriginal children and non-Aboriginal children. Methods: For this population-based cohort study, we used data from a national pediatric end-stage renal disease database. Patients less than 18 years old who started renal replacement treatment (dialysis or kidney transplantation) in nine Canadian provinces (Quebec data were not available) and all three territories between 1992 and 2007 were followed until death, loss to follow-up or end of the study period. We compared initial modality of dialysis and time to first kidney transplant between Aboriginal children, white children and children of other ethnicity. We examined the association between ethnicity and likelihood of kidney transplantation using adjusted Cox proportional hazard models for Aboriginal and white children (data for the children of other ethnicity did not meet the assumptions of proportional hazards). Results: Among 843 pediatric patients included in the study, 104 (12.3%) were Aboriginal, 521 (61.8%) were white, and 218 (25.9%) were from other ethnic minorities. Hemodialysis was the initial modality of dialysis for 48.0% of the Aboriginal patients, 42.7% of the white patients and 62.6% of those of other ethnicity (p < 0.001). The time from start of dialysis to first kidney transplant was longer among the Aboriginal children (median 1.75 years, interquartile range 0.69–2.81) than among the children in the other two groups (p < 0.001). After adjustment for confounders, Aboriginal children were less likely than white children to receive a transplant from a living donor (hazard ratio [HR] 0.36, 95% confidence interval [CI] 0.21–0.61) or a transplant from any donor (HR 0.54, 95% CI 0.40–0.74) during the study period. Interpretation: The time from start of dialysis to first kidney transplant was longer among Aboriginal children than among white children. Further evaluation is needed to determine barriers to transplantation among Aboriginal children.

Overview of the Canadian pediatric end-stage renal disease database

BackgroundPerforming clinical research among pediatric end-stage renal disease patients is challenging. Barriers to successful initiation and completion of clinical research projects include small sample sizes and resultant limited statistical power and lack of longitudinal follow-up for hard clinical end-points in most single center studies.DescriptionExisting longitudinal organ failure disease registry and administrative health datasets available within a universal access health care system can be used to study outcomes of end-stage renal disease among pediatric patients in Canada. To construct the Canadian Pediatric End-Stage Renal Disease database, registry data were linked to administrative health data through deterministic linkage techniques creating a research database which consists of socio-demographic variables, clinical variables, all-cause hospitalizations, and relevant outcomes (death and renal allograft loss) for this patient population. The research database also allows study of major cardiovascular events using previously validated administrative data definitions.ConclusionOrgan failure registry linked to health administrative data can be a powerful tool to perform longitudinal studies in pediatric end-stage renal disease patients. The rich clinical and demographic information found in this database will facilitate study of important medical and non-medical risk factors for death, graft loss and cardiovascular disease among pediatric end-stage renal disease patients.

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

Background: Although Aboriginal adults have a higher risk of end-stage renal disease than non-Aboriginal adults, the incidence and causes of end-stage renal disease among Aboriginal children and young adults are not well described. Methods: We calculated age- and sex-specific incidences of end-stage renal disease among Aboriginal people less than 22 years of age using data from a national organ failure registry. Incidence rate ratios were used to compare rates between Aboriginal and white Canadians. To contrast causes of end-stage renal disease by ethnicity and age, we calculated the odds of congenital diseases, glomerulonephritis and diabetes for Aboriginal people and compared them with those for white people in the following age strata: 0 to less than 22 years, 22 to less than 40 years, 40 to less than 60 years and older than 60 years. Results: Incidence rate ratios of end-stage renal disease for Aboriginal children and young adults (age < 22 yr, v. white people) were 1.82 (95% confidence interval [CI] 1.40–2.38) for boys and 3.24 (95% CI 2.60–4.05) for girls. Compared with white people, congenital diseases were less common among Aboriginal people aged less than 22 years (odds ratio [OR] 0.56, 95% CI 0.36–0.86), and glomerulonephritis was more common (OR 2.18, 95% CI 1.55–3.07). An excess of glomerulonephritis, but not diabetes, was seen among Aboriginal people aged 22 to less than 40 years. The converse was true (higher risk of diabetes, lower risk of glomerulonephritis) among Aboriginal people aged 40 years and older. Interpretation: The incidence of end-stage renal disease is higher among Aboriginal children and young adults than among white children and young adults. This higher incidence may be driven by an increased risk of glomerulonephritis in this population.