Trends in mortality rates on hemodialysis in Canada, 1981–1997

Significant improvements in hemodialysis (HD) have occurred during recent years. Few previous studies have explicitly examined trends in patient outcomes over time. In order to evaluate whether improvements in HD have resulted in decreased mortality, we analyzed trends in mortality rates among the 28,700 patients who initiated HD in Canada during the 1981–1997 period. Mortality rate ratios (RR) were estimated using Poisson regression, and adjusted simultaneously for age, race, gender, primary renal diagnosis and follow-up time. Adjusted mortality rates decreased significantly by calendar period, with RR = 0.90 (95% CI: 0.83–0.96) for 1990–93 and RR = 0.74 (0.69–0.80) for 1994–97, relative to 1981–85 (reference; RR = 1). The decrease was concentrated in the first two years of follow-up. Among causes of death, mortality due to cardiovascular disease showed the sharpest decline. Among subgroups defined by age and diabetes status, mortality improvement was strongest among diabetics age <65 years and weakest among non-diabetics age <65 years. The observed decreases in HD mortality could be due to enhancements in dialysis technology, including improvements in dialysis machines, water purification systems, dialysate composition, and biocompatibility of dialyzer membranes. Key roles were likely played by increased attention to HD adequacy on the part of clinicians, improved nutrition, better management of comorbid conditions, and increased erythropoietin utilization. Detailed data on practice patterns are required in order that the degree of association between trends in dialysis methodology and mortality may be quantitatively evaluated

Projecting renal replacement therapy–specific end-stage renal disease prevalence using registry data

End-stage renal disease incidence and prevalence are increasing in many countries worldwide. Projections of ESRD prevalence are useful for forecasting future resource requirements, and organ failure registry databases are valuable for the development of appropriate projection models. We outline one method of generating renal replacement therapy (RRT)–specific ESRD prevalence projections based on data obtained from the Canadian Organ Replacement Register (CORR). To illustrate the methods, we present national RRT-specific prevalence projections for Canada to the year 2005. Continued large increases in ESRD incidence and prevalence are projected, particularly among diabetics. As of December 31, 1996, there were 17,807 patients receiving RRT in Canada. This number is projected to climb to 32,952 by the end of 2005, for a relative increase of 85% (average relative increase of 5.8% per year). Registry data are a useful basis for future health care planning

The Incidence of Cancer in a Population-Based Cohort of Canadian Heart Transplant Recipients

To assess the long-term risk of developing cancer among heart transplant recipients compared to the Canadian general population, we carried out a retrospective cohort study of 1703 patients who received a heart transplant between 1981 and 1998, identified from the Canadian Organ Replacement Register database. Vital status and cancer incidence were determined through record linkage to the Canadian Mortality Database and Canadian Cancer Registry. Cancer incidence rates among heart transplant patients were compared to those of the general population. The observed number of incident cancers was 160 with 58.9 expected in the general population (SIR = 2.7, 95% CI = 2.3, 3.2). The highest ratios were for non-Hodgkin's lymphoma (NHL) (SIR = 22.7, 95% CI = 17.3, 29.3), oral cancer (SIR = 4.3, 95% CI = 2.1, 8.0) and lung cancer (SIR = 2.0, 95% CI = 1.2, 3.0). Compared to the general population, SIRs for NHL were particularly elevated in the first year posttransplant during more recent calendar periods, and among younger patients. Within the heart transplant cohort, overall cancer risks increased with age, and the 15-year cumulative incidence of all cancers was estimated to be 17%. There is an excess of incident cases of cancer among heart transplant recipients. The relative excesses are most marked for NHL, oral and lung cancer.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79130/1/j.1600-6143.2009.02973.x.pd

Cancer Incidence Among Canadian Kidney Transplant Recipients

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73838/1/j.1600-6143.2007.01736.x.pd

Effect of renal center characteristics on mortality and technique failure on peritoneal dialysis

BACKGROUND: Recent studies report decreased mortality in patients on peritoneal dialysis (PD) over time, suggesting that advances in PD have resulted in improved patient outcomes. Our investigation sought to assess the effect of renal center characteristics on mortality and technique failure (TF) rates. METHODS: Covariates of interest included center-specific cumulative number of PD patients treated, percentage of patients who initiated dialysis on PD, and academic status. Using data obtained from the Canadian Organ Replacement Register, the 17,900 patients who received PD during the 1981 to 1997 period were studied. Mortality and TF rate ratios (RR) were estimated using Poisson regression, adjusting for age, gender, race, primary renal diagnosis, province, follow-up time, and type of PD. RESULTS: As the cumulative number of PD patients treated increased, covariate-adjusted mortality significantly decreased (P < 0.05); a weaker yet significant association was observed between number of PD patients treated and TF. As the percentage of patients initiating dialysis on PD increased, TF rates decreased significantly. No association was observed between center academic status and PD mortality or TF rates. CONCLUSIONS: These results imply that a center's experience with and degree of specialization toward PD impact strongly on PD outcomes. One hypothesis is that a center's propensity to exploit technical and non-technical advances in PD increases directly with these variables. It is also possible that, through experience, centers become more adept at identifying appropriate patients to receive PD. More detailed research is required to evaluate these hypotheses

Effect of renal center characteristics on mortality and technique failure on peritoneal dialysis

BACKGROUND: Recent studies report decreased mortality in patients on peritoneal dialysis (PD) over time, suggesting that advances in PD have resulted in improved patient outcomes. Our investigation sought to assess the effect of renal center characteristics on mortality and technique failure (TF) rates. METHODS: Covariates of interest included center-specific cumulative number of PD patients treated, percentage of patients who initiated dialysis on PD, and academic status. Using data obtained from the Canadian Organ Replacement Register, the 17,900 patients who received PD during the 1981 to 1997 period were studied. Mortality and TF rate ratios (RR) were estimated using Poisson regression, adjusting for age, gender, race, primary renal diagnosis, province, follow-up time, and type of PD. RESULTS: As the cumulative number of PD patients treated increased, covariate-adjusted mortality significantly decreased (P < 0.05); a weaker yet significant association was observed between number of PD patients treated and TF. As the percentage of patients initiating dialysis on PD increased, TF rates decreased significantly. No association was observed between center academic status and PD mortality or TF rates. CONCLUSIONS: These results imply that a center's experience with and degree of specialization toward PD impact strongly on PD outcomes. One hypothesis is that a center's propensity to exploit technical and non-technical advances in PD increases directly with these variables. It is also possible that, through experience, centers become more adept at identifying appropriate patients to receive PD. More detailed research is required to evaluate these hypotheses

The impact of Cenozoic cooling on assemblage diversity in planktonic foraminifera

© 2016 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. The attached file is the published version of the article

End-stage renal disease in Canada: prevalence projections to 2005

BACKGROUND: The incidence and prevalence of end-stage renal disease (ESRD) have increased greatly in Canada over the last 2 decades. Because of the high cost of therapy, predicting numbers of patients who will require dialysis and transplantation is necessary for nephrologists and health care planners. METHODS: The authors projected ESRD incidence rates and therapy-specific prevalence by province to the year 2005 using 1981-1996 data obtained from the Canadian Organ Replacement Register. The model incorporated Poisson regression to project incidence rates, and a Markov model for patient follow-up. RESULTS: Continued large increases in ESRD incidence and prevalence were projected, particularly among people with diabetes mellitus. As of Dec. 31, 1996, there were 17,807 patients receiving renal replacement therapy in Canada. This number was projected to climb to 32,952 by the end of 2005, for a relative increase of 85% and a mean annual increase of 5.8%. The increased prevalence was projected to be greatest for peritoneal dialysis (6.0% annually), followed by hemodialysis (5.9%) and functioning kidney transplant (5.7%). The projected annual increases in prevalence by province ranged from 4.4%, in Saskatchewan, to 7.5%, in Alberta. INTERPRETATION: The projected increases are plausible when one considers that the incidence of ESRD per million population in the United States and other countries far exceeds that in Canada. The authors predict a continued and increasing short-fall in resources to accommodate the expected increased in ESRD prevalence

Phylogeography and cryptic diversity of the solitary-dwelling silvery mole-rat, genus Heliophobius (family: Bathyergidae)

Alongside the eusocial naked mole-rat, Heterocephalus glaber, Heliophobius argenteocinereus represents the second oldest lineage within the African mole-rat family Bathyergidae, and phylogenetically intermediate between the East African Het. glaber and the South African genera Bathyergus and Georychus. Across its geographic range, Hel.. argenteocinereus is widely distributed on both sides of the East African Rift System (EARS), and is a key taxon for understanding the phylogeographic patterns of divergence of the family as a whole. Phylogenetic analysis of 62 mitochondrial cyt b sequences, representing 48 distinct haplotypes from 26 geographic locations across the range of Heliophobius, consistently and robustly resolved six genetically divergent clades that we recognize as distinct evolutionary species. Early species descriptions of Heliophobius were synonymized into a monotypic taxonomy that recognized only Hel. argentocinereus. These synonyms constitute available names for these rediscovered cryptic lineages, for which combined morphological and genetic evidence for topotypical populations endorses the recognition of six to eight distinct taxa. Bayesian estimates of diver- gence times using the fossil Proheliophobius as a calibration for the molecular clock suggest that the adaptive radiation of the genus began in the early Miocene, and that cladogenesis, represented in the extant species, reflects a strident signa- ture of tectonic activity that forged the principal graben in the EARS.SYNTHESYS grant (BE-TAF-289), grants from the National Research Foundation, the University of Pretoria South Africa (to NCB) and the ERANDA and Bay Foundations (FC).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1469-7998ab201