Dialyse à domicile : évaluation du modèle de dialyse à domicile intégrée

Les modalités de dialyse à domicile, soit la dialyse péritonéale (DP) et l’hémodialyse à domicile (HDD), offrent plusieurs avantages aux patients avec insuffisance rénale terminale (IRT), que ce soit par rapport à la qualité de vie ou à une diminution des complications liées à l’IRT. Peu de données sont toutefois disponibles quant aux répercussions cliniques de l’initiation de la thérapie de suppléance rénale via la DP ou l’HDD et de l’optimisation subséquente du traitement à domicile. Le présent mémoire visait donc à répondre aux trois questions suivantes soit (1) la comparaison entre la survie des patients débutant la thérapie de suppléance rénale par une ou l’autre des modalités à domicile, (2) l’évaluation du modèle de dialyse à domicile intégrée (c’est la dire l’initiation de la suppléance rénale en DP avec un transfert subséquent en HDD) et (3) l’évaluation des prédicteurs dudit modèle de dialyse à domicile intégrée. L’évaluation de 11 416 patients ayant débuté la suppléance rénale en Australie et Nouvelle-Zélande entre 2000 et 2012 a montré une association entre une mortalité globale inférieure chez les patients traités par HDD comparativement à ceux traités par DP (rapport des risques [hazard ratio - HR] 0.47, intervalle de confiance [IC] de 95%, 0.38-0.59). Par contre, les patients ayant débuté la suppléance rénale en DP et ayant ensuite été transférés en HDD (modèle de dialyse à domicile intégrée) avaintt une survie en dialyse à domicile similaire à ceux directement traités par l’HDD (HR 0.92, IC de 95%, 0.52-1.62). Finalement, les caractéristiques démographiques de base (jeune âge, sexe masculin, ethnie), les comorbidités, la cause de l’insuffisance rénale terminale, la durée du traitement et la raison de l’arrêt de la DP étaient des prédicteurs du modèle de dialyse à domicile intégrée.

Analysing Seasonal Health Data

Seasonal patterns have been found in a remarkable range of health conditions, including birth defects, respiratory infections and cardiovascular disease. Accurately estimating the size and timing of seasonal peaks in disease incidence is an aid to understanding the causes and possibly to developing interventions. With global warming increasing the intensity of seasonal weather patterns around the world, a review of the methods for estimating seasonal effects on health is timely. This is the first book on statistical methods for seasonal data written for a health audience. It describes methods for a range of outcomes (including continuous, count and binomial data) and demonstrates appropriate techniques for summarising and modelling these data. It has a practical focus and uses interesting examples to motivate and illustrate the methods. The statistical procedures and example data sets are available in an R package called ‘season’. Adrian Barnett is a senior research fellow at Queensland University of Technology, Australia. Annette Dobson is a Professor of Biostatistics at The University of Queensland, Australia. Both are experienced medical statisticians with a commitment to statistical education and have previously collaborated in research in the methodological developments and applications of biostatistics, especially to time series data. Among other projects, they worked together on revising the well-known textbook "An Introduction to Generalized Linear Models," third edition, Chapman Hall/CRC, 2008. In their new book they share their knowledge of statistical methods for examining seasonal patterns in health.

Acute poststreptococcal glomerulonephritis : public health implications of recent clusters in New South Wales and epidemiology of hospital admissions

Acute poststreptococcal glomerulonephritis (APSGN) is an inflammatory kidney condition that can complicate Group A streptococcal infections. Two clusters of APSGN occurred recently in New South Wales (NSW), Australia; one in a rural town in December 1999 and the other in a Sydney suburb in January 2000. We interviewed carers of the affected children but found no common exposures except three of the Sydney cases were cousins in frequent contact. To assess the probability of these clusters occurring, we analysed hospital admissions for acute glomerulonephritis, as a proxy for APSGN in younger patients. The incidence of acute glomerulonephritis in NSW during 1989/90-1997/8 in residents aged under 20 years was 2(.)2/100000/year (95% CI 2(.)0-2(.)5). Incidence was highest in children aged 5-9 years, boys and Aboriginal children. We found no evidence for other clusters during that period. The recent clusters highlight the continued potential for unexpected future outbreaks of APSGN.

Introduction to disaster epidemiology for public health personnel

There has been a renewed interest in disaster epidemiology after the World Trade Center and Pentagon terrorist attacks of 2001, the devastation of Hurricane Katrina and the overwhelming loss of life that resulted from the tsunami that originated in the Indian Ocean and struck Indonesia and other adjacent countries on December 26, 2004. Institutions that have accepted the challenge of training the next generation of public health professionals as well as to continue the education of the dedicated professionals already serving in public health fields have a responsibility to train practitioners in the basic principles of disaster epidemiology as well as in practical applications of these principles. This culminating experience project involved developing an on-line course complete with the background information as well as relevant case studies that can be used as a curriculum for an introductory course in disaster epidemiology. ^

A Bayesian analysis for spatial processes with application to mapping

In geographical epidemiology, maps of disease rates and disease risk provide a spatial perspective for researching disease etiology. For rare diseases or when the population base is small, the rate and risk estimates may be unstable. Empirical Bayesian (EB) methods have been used to spatially smooth the estimates by permitting an area estimate to "borrow strength" from its neighbors. Such EB methods include the use of a Gamma model, of a James-Stein estimator, and of a conditional autoregressive (CAR) process. A fully Bayesian analysis of the CAR process is proposed. One advantage of this fully Bayesian analysis is that it can be implemented simply by using repeated sampling from the posterior densities. Use of a Markov chain Monte Carlo technique such as Gibbs sampler was not necessary. Direct resampling from the posterior densities provides exact small sample inferences instead of the approximate asymptotic analyses of maximum likelihood methods (Clayton & Kaldor, 1987). Further, the proposed CAR model provides for covariates to be included in the model. A simulation demonstrates the effect of sample size on the fully Bayesian analysis of the CAR process. The methods are applied to lip cancer data from Scotland, and the results are compared. ^

A STUDY ON THE EPIDEMIOLOGY OF POSITIVE PHYSICAL HEALTH (NHANES I)

HANES 1 detailed sample data were used to operationalize a definition of health in the absence of disease and to describe and compare the characteristics of the normal (healthy) group versus an abnormal (unhealthy) group.^ Parallel screening gave a 3.8 percent prevalence proportion of physical health, with a female:male ratio of 2:1 and younger ages in the healthy group. Statistically significant Mantel-Haenszel gender-age-adjusted odds ratios (MHOR) were estimated among abnormal non-migrants (1.53), skilled workers/unemployed (1.76), annual family incomes of less than $10,000 (1.56), having ever smoked (1.58), and started smoking before 18 years of age (1.58). Significant MHOR were also found for abnormals for health promoting measures: non-iodized salt use (1.94), needed dental care (1.91); and for fair to poor perceived health (4.28), perceiving health problems (2.52), and low energy level (1.68). Significant protective effects for much to moderate recreational exercise (MHOR 0.42) and very active to moderate non-recreational activity (MHOR 0.49) were also obtained. Covariance analysis additive models detected statistically significant higher mean values for abnormals than normals for serum magnesium, hemoglobin, hematocrit, urinary creatinine, and systolic and diastolic blood pressures, and lower values for abnormals than normals for serum iron. No difference was detected for serum cholesterol. Significant non-additive joint effects were found for body mass index.^ The results suggest positive physical health can be measured with cross-sectional survey data. Gender differentials, and associations between ecologic, socioeconomic, hazardous risk factors, health promoting activities and physical health are in general agreement with published findings on studies of morbidity. Longitudinal prospective studies are suggested to establish the direction of the associations and to enhance present knowledge of health and its promoting factors. ^

THE EPIDEMIOLOGY AND HEALTH ECONOMICS OF ANKLE INJURIES

The thesis focuses on a central theme of the epidemiology and health economics of ankle sprains to inform health policy and the provision of health services. It describes the burden, prognosis, resource utilization, and costs attributed to these injuries. The first manuscript systematically reviewed 34 studies on the direct and indirect costs of treating ankle and foot injuries. The overall costs per patient ranged from $2,075- $3,799 (2014 USD) for ankle sprains; $290-$20,132 for ankle fractures; and $6,345-$45,731 for foot fractures, reflecting differences in injury severity, treatment methods, and study characteristics. The second manuscript provided an epidemiological and economic profile of non-fracture ankle and foot injuries in Ontario using linked databases from the Institute for Clinical Evaluative Sciences. The incidence rate of ankle sprains was 16.9/1,000 person-years. Annually, ankle and foot injuries cost $21,685,876 (2015 CAD). The mean expenses per case were $99.98 (95% CI, $99.70-100.26) for any injury. Costs ranged from $133.78-$210.75 for ankle sprains and $1,497.12-$1,755.69 for dislocations. The third manuscript explored the impact of body mass index on recovery from medically attended grade 1 and 2 ankle sprains using the Foot and Ankle Outcome Score. Data came from a randomized controlled trial of a physiotherapy intervention in Kingston, Ontario. At six months, the odds ratio of recovery for participants with obesity was 0.60 (0.37-0.97) before adjustment and 0.74 (0.43-1.29) after adjustment compared to non-overweight participants. The fourth manuscript used trial data to examine the health-related quality of life among ankle sprain patients using the Health Utilities Index version 3 (HUI-3). The greatest improvements in scores were seen at one month post-injury (HUI-3: 0.88, 95% CI: 0.86-0.90). Individuals with grade 2 sprains had significantly lower ambulation scores than those with grade 1 sprains (0.70 vs. 0.84; p<0.05). The final manuscript used trial data to describe the financial burden (direct and indirect costs) of ankle sprains. The overall mean costs were $1,508 (SD: $1,452) at one month and increased to $2,206 (SD: $3,419) at six months. Individuals with more severe injuries at baseline had significantly higher (p<0.001) costs compared to individuals with less severe injuries, after controlling for confounders.

The Epidemiology and Health Economics of Ankle Injuries

Thesis (Ph.D, Community Health & Epidemiology) -- Queen's University, 2016-10-03 22:59:05.858

The waddlia genome: A window into chlamydial biology

Growing evidence suggests that a novel member of the Chlamydiales order, Waddlia chondrophila, is a potential agent of miscarriage in humans and abortion in ruminants. Due to the lack of genetic tools to manipulate chlamydia, genomic analysis is proving to be the most incisive tool in stimulating investigations into the biology of these obligate intracellular bacteria. 454/Roche and Solexa/Illumina technologies were thus used to sequence and assemble de novo the full genome of the first representative of the Waddliaceae family, W. chondrophila. The bacteria possesses a 2′116′312bp chromosome and a 15′593 bp low-copy number plasmid that might integrate into the bacterial chromosome. The Waddlia genome displays numerous repeated sequences indicating different genome dynamics from classical chlamydia which almost completely lack repetitive elements. Moreover, W. chondrophila exhibits many virulence factors also present in classical chlamydia, including a functional type III secretion system, but also a large complement of specific factors for resistance to host or environmental stresses. Large families of outer membrane proteins were identified indicating that these highly immunogenic proteins are not Chlamydiaceae specific and might have been present in their last common ancestor. Enhanced metabolic capability for the synthesis of nucleotides, amino acids, lipids and other co-factors suggests that the common ancestor of the modern Chlamydiales may have been less dependent on their eukaryotic host. The fine-detailed analysis of biosynthetic pathways brings us closer to possibly developing a synthetic medium to grow W. chondrophila, a critical step in the development of genetic tools. As a whole, the availability of the W. chondrophila genome opens new possibilities in Chlamydiales research, providing new insights into the evolution of members of the order Chlamydiales and the biology of the Waddliaceae.

The impact of temperature on mortality in Tianjin, China : a case-crossover design with a distributed lag non-linear model

Background There has been increasing interest in assessing the impacts of temperature on mortality. However, few studies have used a case–crossover design to examine non-linear and distributed lag effects of temperature on mortality. Additionally, little evidence is available on the temperature-mortality relationship in China, or what temperature measure is the best predictor of mortality. Objectives To use a distributed lag non-linear model (DLNM) as a part of case–crossover design. To examine the non-linear and distributed lag effects of temperature on mortality in Tianjin, China. To explore which temperature measure is the best predictor of mortality; Methods: The DLNM was applied to a case¬−crossover design to assess the non-linear and delayed effects of temperatures (maximum, mean and minimum) on deaths (non-accidental, cardiopulmonary, cardiovascular and respiratory). Results A U-shaped relationship was consistently found between temperature and mortality. Cold effects (significantly increased mortality associated with low temperatures) were delayed by 3 days, and persisted for 10 days. Hot effects (significantly increased mortality associated with high temperatures) were acute and lasted for three days, and were followed by mortality displacement for non-accidental, cardiopulmonary, and cardiovascular deaths. Mean temperature was a better predictor of mortality (based on model fit) than maximum or minimum temperature. Conclusions In Tianjin, extreme cold and hot temperatures increased the risk of mortality. Results suggest that the effects of cold last longer than the effects of heat. It is possible to combine the case−crossover design with DLNMs. This allows the case−crossover design to flexibly estimate the non-linear and delayed effects of temperature (or air pollution) whilst controlling for season.

Challenges to environmental toxicology and epidemiology : where do we stand and which way do we go?

Modern toxicology investigates a wide array of both old and new health hazards. Priority setting is needed to select agents for research from the plethora of exposure circumstances. The changing societies and a growing fraction of the aged have to be taken into consideration. A precise exposure assessment is of importance for risk estimation and regulation. Toxicology contributes to the exploration of pathomechanisms to specify the exposure metrics for risk estimation. Combined effects of co-existing agents are not yet sufficiently understood. Animal experiments allow a separate administration of agents which can not be disentangled by epidemiological means, but their value is limited for low exposure levels in many of today’s settings. As an experimental science, toxicology has to keep pace with the rapidly growing knowledge about the language of the genome and the changing paradigms in cancer development. During the pioneer era of assembling a working draft of the human genome, toxicogenomics has been developed. Gene and pathway complexity have to be considered when investigating gene–environment interactions. For a best conduct of studies, modern toxicology needs a close liaison with many other disciplines like epidemiology and bioinformatics.

Pregnancy losses in young Australian women : findings from the Australian Longitudinal Study on Women's Health

INTRODUCTION: Little research has examined recognized pregnancy losses in a general population. Data from an Australian cohort study provide an opportunity to quantify this aspect of fecundity at a population level. METHOD: Participants in the Australian Longitudinal Study on Women's Health who were aged 28-33 years in 2006 (n = 9,145) completed up to 4 mailed surveys over 10 years. Participants were categorized according to the recognized outcome of their pregnancies, including live birth, miscarriage/stillbirth, termination/ectopic, or no pregnancy. RESULTS: At age 18-23, more women reported terminations (7%) than miscarriages (4%). By 28-33 years, the cumulative frequency of miscarriage (15%) was as common as termination (16%). For women aged 28-33 years who had ever been pregnant (n = 5,343), pregnancy outcomes were as follows: birth only (50%); loss only (18%); and birth and loss (32%), of which half (16%) were birth and miscarriage. A comparison between first miscarriage and first birth (no miscarriage) showed that most first miscarriages occurred in women aged 18-23 years who also reported a first birth at the same survey (15%). Half (51%) of all first births and first miscarriages in women aged 18-19 ended in miscarriage. Early childbearers (<28 years) often had miscarriages around the same time period as their first live birth, suggesting proactive family formation. Delayed childbearers (32-33 years) had more first births than first miscarriages. CONCLUSION: Recognized pregnancy losses are an important measure of fecundity in the general population because they indicate successful conception and maintenance of pregnancy to varying reproductive endpoints.

Infertility, medical advice and treatment with fertility hormones and/or in vitro fertilisation: a population perspective from the Australian Longitudinal Study on Women's Health

OBJECTIVE: To identify the factors associated with infertility, seeking advice and treatment with fertility hormones and/or in vitro fertilisation (IVF) among a general population of women. METHODS: Participants in the Australian Longitudinal Study on Women's Health aged 28-33 years in 2006 had completed up to four mailed surveys over 10 years (n=9,145). Parsimonious multivariate logistic regression was used to identify the socio-demographic, biological (including reproductive histories), and behavioural factors associated with infertility, advice and hormonal/IVF treatment. RESULTS: For women who had tried to conceive or had been pregnant (n=5,936), 17% reported infertility. Among women with infertility (n=1031), 72% (n=728) sought advice but only 50% (n=356) used hormonal/IVF treatment. Women had higher odds of infertility when: they had never been pregnant (OR=7.2, 95% CI 5.6-9.1) or had a history of miscarriage (OR range=1.5-4.0) than those who had given birth (and never had a miscarriage or termination). CONCLUSION: Only one-third of women with infertility used hormonal and/or IVF treatment. Women with PCOS or endometriosis were the most proactive in having sought advice and used hormonal/IVF treatment. IMPLICATIONS: Raised awareness of age-related declining fertility is important for partnered women aged approximately 30 years to encourage pregnancy during their prime reproductive years and reduce the risk of infertility.

Predictors of sexually transmitted infection in Australian women : evidence from the Australian longitudinal study on women’s health

This longitudinal study examined characteristics of women diagnosed with sexually transmitted infections (STI) for the first time in their later 20s and early 30s. Participants were 6,840 women (born 1973–1978) from the Australian Longitudinal Study on Women’s Health. Women aged 18–23 years were surveyed in 1996 (S1), 2000 (S2), 2003 (S3), and 2006 (S4). There were 269 women reporting an STI for the first time at S3 or S4. Using two multivariable logistic regression analyses (examining 18 predictor variables), these 269 women were compared (1) with 306 women who reported an STI at S2 and (2) with 5,214 women who never reported an STI across the four surveys. Women who reported an STI for the first time at S3 or S4 were less likely to have been pregnant or had a recent Pap smear compared to women reporting an STI at S2.Women reporting a first STI at S3 or S4 were less likely to have been pregnant or had a recent Pap smear compared to women reporting an STI at S2. Women were more likely to report an STI for the first time at S3 or S4 compared to women not reporting an STI at any survey if they were younger, unpartnered, had a higher number of sexual partners, had never been pregnant, were recently divorced or separated, and reported poorer access to Women’s Health or Family Planning Centres at S2. These findings demonstrate the value of longitudinal studies of sexual health over the life course beyond adolescence.