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Featured researches published by David Ansell.


JAMA | 2009

Cardiovascular and noncardiovascular mortality among patients starting dialysis

Dinanda J. de Jager; Diana C. Grootendorst; Kitty J. Jager; Paul C. van Dijk; Lonneke M. J. Tomas; David Ansell; Frederic Collart; Patrik Finne; James G. Heaf; Johan De Meester; Jack F.M. Wetzels; Frits R. Rosendaal; Friedo W. Dekker

CONTEXT Cardiovascular mortality is considered the main cause of death in patients receiving dialysis and is 10 to 20 times higher in such patients than in the general population. OBJECTIVE To evaluate if high overall mortality in patients starting dialysis is a consequence of increased cardiovascular mortality risk only or whether noncardiovascular mortality is equally increased. DESIGN, SETTING, AND PATIENTS Using data from between January 1, 1994, and January 1, 2007, age-stratified mortality in a European cohort of adults starting dialysis and receiving follow-up for a mean of 1.8 (SD, 1.1) years (European Renal Association-European Dialysis and Transplant Association [ERA-EDTA] Registry [N = 123,407]) was compared with the European general population (Eurostat). MAIN OUTCOME MEASURES Cause of death was recorded by ERA-EDTA codes in patients and matching International Statistical Classification of Diseases, 10th Revision codes in the general population. Standardized cardiovascular and noncardiovascular mortality rates, their ratio, difference, and relative excess of cardiovascular over noncardiovascular mortality were calculated. RESULTS Overall all-cause mortality rates in patients and the general population were 192 per 1000 person-years (95% confidence interval [CI], 190-193) and 12.055 per 1000 person-years (95% CI, 12.05-12.06), respectively. Cause of death was known for 90% of the patients and 99% of the general population. In patients, 16,654 deaths (39%) were cardiovascular and 21,654 (51%) were noncardiovascular. In the general population, 7,041,747 deaths (40%) were cardiovascular and 10,183,322 (58%) were noncardiovascular. Cardiovascular and noncardiovascular mortality rates in patients were respectively 38.1 per 1000 person-years (95% CI, 37.2-39.0) and 50.1 per 1000 person-years (95% CI, 48.9-51.2) higher than in the general population. On a relative scale, standardized cardiovascular and noncardiovascular mortality were respectively 8.8 (95% CI, 8.6-9.0) and 8.1 (95% CI, 7.9-8.3) times higher than in the general population. The ratio of these rates, ie, relative excess of cardiovascular over noncardiovascular mortality in patients starting dialysis compared with the general population, was 1.09 (95% CI, 1.06-1.12). Relative excess in a sensitivity analysis in which unknown/missing causes of death were regarded either as noncardiovascular or cardiovascular varied between 0.90 (95% CI, 0.88-0.93) and 1.39 (95% CI, 1.35-1.43). CONCLUSION Patients starting dialysis have a generally increased risk of death that is not specifically caused by excess cardiovascular mortality.


The New England Journal of Medicine | 1986

Transfers to a Public Hospital

Robert L. Schiff; David Ansell; James E. Schlosser; Ahamed H. Idris; Ann Morrison; Steven Whitman

In recent years there has been a dramatic increase in the number of patients transferred to public hospitals in the United States. We prospectively studied 467 medical and surgical patients who were transferred from the emergency departments of other hospitals in the Chicago area to Cook County Hospital and subsequently admitted. Eighty-nine percent of the transferred patients were black or Hispanic, and 81 percent were unemployed. Most (87 percent) were transferred because they lacked adequate medical insurance. Only 6 percent of the patients had given written informed consent for transfer. Twenty-two percent required admission to an intensive care unit, usually within 24 hours of arrival. Twenty-four percent were in an unstable clinical condition at the transferring hospital. The proportion of transferred medical-service patients who died was 9.4 percent, which was significantly higher than the proportion of medical-service patients who were not transferred (3.8 percent, P less than 0.01). There was no significant difference in the proportion of deaths on the surgical service between patients who were transferred and those who were not (1.5 vs. 2.4 percent). We conclude that patients are transferred to public hospitals predominantly for economic reasons, in spite of the fact that many of them are in an unstable condition at the time of transfer.


Nephron Clinical Practice | 2013

UK Renal Registry 17th Annual Report: Chapter 5 Survival and Cause of Death in UK Adult Patients on Renal Replacement Therapy in 2013: National and Centre-specific Analyses.

David Ansell; Paul Roderick; Alex Hodsman; Daniel Ford; Retha Steenkamp; Charles R.V. Tomson

Introduction: These analyses examine survival from the start of renal replacement therapy (RRT), based on the total incident UK dialysis population reported to the Registry, including the 21% who started on PD and the 5% who received a pre-emptive transplant. Survival of prevalent patients and changes in survival between 1997–2006 are reported. The article includes a discussion on the technical definition for the date of start of both PD and HD. Methods: Survival was calculated for both incident and prevalent patients on RRT and compared between the UK countries after adjustment for age. Survival of incident patients (starting during 2006) was calculated with and without a 90 day RRT start cut off. Survival of incident patients is shown with and without censoring at transplantation. Both the Kaplan–Meier and Cox adjusted models were used to calculate survival. Causes of death were analysed for both groups. Relative risk of death was calculated compared with the general UK population. Results: The 2006 unadjusted 1 year after 90 day survival for patients starting RRT was 86%. In incident 18–64 year olds the unadjusted 1 year survival had risen from 85.9% in 1997 to 91.5% in 2006 and for those aged ≥ 65 it had risen from 63.8% to 72.9%. The age adjusted survival of prevalent dialysis patients rose from 85% in 2000 to 89% in 2007. Diabetic patient survival rose from 76.6% in 2000 to 84.0% in 2007. The relative risk of death on RRT compared with the general population was 30 at age 30 years compared with 3 at age 80 years. In the prevalent RRT dialysis population, cardiovascular disease accounted for 34% of deaths, infection 20% and treatment withdrawal 14%. Conclusions: Incident and prevalent patient survival on RRT in all the UK countries for all age ranges and also for patients with diabetes continued to improve. The relative risk of death on RRT compared with the general population has fallen since 2001. Death rates on dialysis in the UK remained lower than when compared with a similar aged population on dialysis in the USA.


Nephrology Dialysis Transplantation | 2009

Residual renal function at the start of dialysis and clinical outcomes

Vianda S. Stel; Friedo W. Dekker; David Ansell; Hans Augustijn; Francesco G. Casino; Frederic Collart; Patrik Finne; George A. Ioannidis; Mario Salomone; Jamie P. Traynor; Oscar Zurriaga; Enrico Verrina; Kitty J. Jager

BACKGROUND This study evaluates the association between estimated GFR (eGFR) at the start of dialysis and mortality within Europe. METHODS Renal registries participating in the ERA-EDTA Registry were asked to provide data on serum creatinine recorded 0-4 weeks before the start of dialysis in incident dialysis patients in 1999 and 2003. Within this cohort study, data were available in 11 472 patients from nine national or regional European renal registries. Cox regression analyses were performed to examine the association between GFR estimated by the four-variable MDRD equation (eGFR) and all-cause mortality, using a follow-up through 31 December 2005. RESULTS In the 2003 data, the mean eGFR was 8.6 ml/min/1.73 m(2). The unadjusted survival analyses showed that an increase in eGFR of 1 ml/min/1.73 m(2) was associated with a higher mortality risk (HR = 1.03; 95% CI: 1.03-1.04) that remained similar after adjustment for age, gender, primary renal disease, treatment modality, country and comorbidity. The findings were consistent across gender, treatment modalities, geographical regions and time periods (2003 versus 1999), but the association between a higher eGFR at the start of dialysis and mortality was the strongest in the youngest age groups and in patients with glomerulonephritis. Analyses at centre level showed that a 10% increase in the percentage of patients starting dialysis at high eGFR levels (>or=10.5 ml/min) was associated with a 22% higher mortality risk (HR = 1.22; 95% CI: 1.18-1.26). CONCLUSIONS This European study showed that a higher eGFR at the start of dialysis was associated with a higher mortality risk. However, an answer to the question when to start dialysis needs to come from randomized controlled trials.


Nephrology Dialysis Transplantation | 2009

An update on renal replacement therapy in Europe: ERA–EDTA Registry data from 1997 to 2006

Anneke Kramer; Vianda S. Stel; Carmine Zoccali; James G. Heaf; David Ansell; Carola Grönhagen-Riska; Torbjørn Leivestad; Keith Simpson; Runolfur Palsson; Kitty J. Jager

BACKGROUND Recent studies have indicated a stabilization in the incidence rates of renal replacement therapy (RRT) for end-stage renal disease (ESRD) in a number of European countries. The aim of this study was to provide an update on the incidence, prevalence and outcomes of RRT in Europe over the past decade. METHODS Nineteen European national or regional renal registries with registry data from 1997 to 2006 participated in the study. Incidence and prevalence trends were analysed with Poisson and Joinpoint regression. Cox regression methods were used to examine patient survival. RESULTS The total adjusted incidence rate of RRT for ESRD increased from 109.9 per million population (pmp) in 1997 to 119.7 pmp in 2000, i.e. an average annual percentage change (AAPC) of 2.9% (95% CI 2.1-3.8%). Thereafter, the incidence increased at a much lower rate to 125.4 pmp in 2006 [AAPC 0.6% (95% CI 0.3-0.8%)]. This change in the trend of the incidence of RRT was largely due to a stabilization in the incidence rates of RRT for females aged 65-74 years, males aged 75-84 years and patients receiving RRT for ESRD due to hypertension/renal vascular disease. The overall adjusted prevalence in Europe continued to increase linearly at 2.7% per year. Between the periods 1997-2001 and 2002-2006, the risk of death decreased for all treatment modalities, with the most substantial improvement in patients starting peritoneal dialysis [19% (95% CI 15-22%)] and in patients receiving a kidney transplant [17% (95% CI 11-23%)]. CONCLUSION This European study shows that the annual rise of the overall incidence rate of RRT for ESRD has diminished and that in several age groups the incidence rates have now stabilized. The survival of dialysis patients and kidney transplant recipients has continued to improve.


American Journal of Kidney Diseases | 2011

Predicting Mortality in Incident Dialysis Patients: An Analysis of the United Kingdom Renal Registry

Martin Wagner; David Ansell; David M. Kent; John L. Griffith; David Naimark; Christoph Wanner; Navdeep Tangri

BACKGROUND The risk of death in dialysis patients is high, but varies significantly among patients. No prediction tool is used widely in current clinical practice. We aimed to predict long-term mortality in incident dialysis patients using easily obtainable variables. STUDY DESIGN Prospective nationwide multicenter cohort study in the United Kingdom (UK Renal Registry); models were developed using Cox proportional hazards. SETTING & PARTICIPANTS Patients initiating hemodialysis or peritoneal dialysis therapy in 2002-2004 who survived at least 3 months on dialysis treatment were followed up for 3 years. Analyses were restricted to participants for whom information for comorbid conditions and laboratory measurements were available (n = 5,447). The data set was divided into data sets for model development (n = 3,631; training) and validation (n = 1,816) using random selection. PREDICTORS Basic patient characteristics, comorbid conditions, and laboratory variables. OUTCOMES All-cause mortality censored for kidney transplant, recovery of kidney function, and loss to follow-up. RESULTS In the training data set, 1,078 patients (29.7%) died within the observation period. The final model for the training data set included patient characteristics (age, race, primary kidney disease, and treatment modality), comorbid conditions (diabetes, history of cardiovascular disease, and smoking), and laboratory variables (hemoglobin, serum albumin, creatinine, and calcium levels); reached a C statistic of 0.75 (95% CI, 0.73-0.77); and could discriminate accurately among patients with low (6%), intermediate (19%), high (33%), and very high (59%) mortality risk. The model was applied further to the validation data set and achieved a C statistic of 0.73 (95% CI, 0.71-0.76). LIMITATIONS Number of missing comorbidity data and lack of an external validation data set. CONCLUSIONS Basic patient characteristics, comorbid conditions, and laboratory variables can predict 3-year mortality in incident dialysis patients with sufficient accuracy. Identification of subgroups of patients according to mortality risk can guide future research and subsequently target treatment decisions in individual patients.


Cancer | 1993

Referral adherence in an inner city breast and cervical cancer screening program

Loretta Lacey; Jennifer Whitfield; Wini Dewhite; David Ansell; Steven Whitman; Edwin H. Chen; Clyde W. Phillips

Background. Early detection and immediate follow‐up treatment for cancer of the breast and cervix can reduce morbidity and mortality. This report describes adherence to follow‐up appointments for suspected breast and cervical malignancies in a population of low‐income black women who participated in a community‐based nurse‐managed screening program.


Annals of Internal Medicine | 2011

Narrative review: tetanus--a health threat after natural disasters in developing countries

Majid Afshar; Mahesh Raju; David Ansell; Thomas P. Bleck

Tetanus is an expected complication when disasters strike in developing countries, where tetanus immunization coverage is often low or nonexistent. Collapsing structures and swirling debris inflict numerous crush injuries, fractures, and serious wounds. Clostridium tetani infects wounds contaminated with dirt, feces, or saliva and releases neurotoxins that may cause fatal disease. Clusters of infections have recently occurred after tsunamis and earthquakes in Indonesia, Kashmir, and Haiti. The emergency response to clusters of tetanus infections in developing countries after a natural disaster requires a multidisciplinary approach in the absence of an intensive care unit, readily available resources, and a functioning cold-chain system. It is essential that injured people receive immediate surgical and medical care of contaminated, open wounds with immunization and immunoglobulin therapy. Successful treatment of tetanus depends on prompt diagnosis of clinical tetanus, treatment to ensure neutralization of circulating toxin and elimination of C. tetani infection, control of spasms and convulsions, maintenance of the airway, and management of respiratory failure and autonomic dysfunction.


Cancer Causes & Control | 2007

The black:white disparity in breast cancer mortality: the example of Chicago

Jocelyn Hirschman; Steven Whitman; David Ansell

ObjectiveThe black:white disparity in breast cancer mortality has been increasing in the U.S. In order to gain insight into this disparity in Chicago, we examined mortality data together with other important measures associated with breast cancer.MethodsTrends in black:white female breast cancer mortality, incidence, stage at diagnosis, and mammography screening in Chicago were examined using data from the Illinois State Cancer Registry, Illinois Department of Public Health Vital Records, and the Illinois Behavioral Risk Factor Surveillance System.ResultsThe breast cancer mortality rate for black women in Chicago for 1999–2003 was 49% higher than that of white women, but the disparity is a recent phenomenon that is increasing rapidly. In 2003 the black rate was 68% higher than the white rate. Mortality rates were similar in the 1980’s and only started to diverge in the 1990’s as a result of a sharp improvement in mortality among white women contrasted with no improvement for black women. This lack of progress for black women is perplexing given that self-reported mammography screening rates have been the same for blacks and whites in Chicago since at least 1996 and that the early detection of breast cancer for black women has been increasing.ConclusionsThere has been no improvement in mortality from breast cancer for black women in Chicago in 23 years. This study, along with a review of the literature, lends support to the hypothesis that the disparities in breast cancer mortality are due to differential access to mammography, differential quality in mammography, and differential access to treatment for breast cancer. Fortunately, all three are amenable to intervention, which would help ameliorate this unacceptable disparity.


Transplantation | 2009

Factors That Influence Access to the National Renal Transplant Waiting List

Christopher Dudley; Rachel J. Johnson; Helen L. Thomas; Rommel Ravanan; David Ansell

Background. Registry data can be used to examine whether there are differences between individual renal units in the proportion of dialysis patients listed for renal transplantation, to investigate possible reasons for any differences observed, and to discover whether highlighting these anomalies can influence practice. Methods. A cross-sectional study of 12, 401 prevalent adult dialysis patients from 41 renal units across England and Wales was performed. The proportion of patients registered on the deceased donor transplant waiting list was determined for each renal unit. Patient- and center-specific factors that influence the probability of being listed for transplantation were identified and used to adjust for differences observed between units. The annual change in the size of the transplant waiting list was examined before and after presentation of these data. Results. A total of 23.3% of patients were active on the transplant waiting list. Patient. Specific variables significantly associated with listing were age, primary renal disease, graft number, social deprivation, and ethnicity but not gender. Centre-specific variables included size of renal unit, size of living donor program, and listing practice for living donor transplantation. Whether the renal unit was also a transplant unit was not significant. After adjusting for these variables, there remained unexplained variation between renal units in the proportion of dialysis patients on the waiting list. An increase in the number of patients listed for transplantation has been observed since presenting these data. Conclusions. Differences in listing practice exist between centers that cannot be explained by the patient case mix or center characteristics examined.

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Ken Farrington

University of Hertfordshire

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Paul Roderick

University of Southampton

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Farida Hussain

University of Nottingham

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