Diagnostics For Mixture Regression Models: Applications To Public Health
Funder
National Health and Medical Research Council
Funding Amount
$128,250.00
Summary
In many public health studies, finite mixture regression models are often used to analyse data arising from heterogeneous populations. It is important to assess the stability of parameter estimates and the validity of statistical inferences when the underlying assumptions appear to be violated, but appropriate diagnostics are lacking in the literature. This research aims to develop effective diagnostic methods for assessing the adequacy of mixture regression models and the sensitivity of accompa ....In many public health studies, finite mixture regression models are often used to analyse data arising from heterogeneous populations. It is important to assess the stability of parameter estimates and the validity of statistical inferences when the underlying assumptions appear to be violated, but appropriate diagnostics are lacking in the literature. This research aims to develop effective diagnostic methods for assessing the adequacy of mixture regression models and the sensitivity of accompanying test statistics. The methodology developed will enable health care professionals to focus on substantive issues and to draw accurate and valid conclusions inferred from correlated and over-dispersed outcomes. In the presence of anomalous observations, the influence diagnostics can provide insights into the source of heterogeneity and the apparent over-dispersion, while accommodating the inherent correlation due to the longitudinal study design or nested data structure. Significance of the research lies in its scientific novelty and the breadth of its practical applications. The benefits to public health will accrue both nationally and internationally. For the empirical studies that motivated and are linked to this research, evaluation of health outcomes has significant implications in the prevention and control of recurrent urinary tract infections, hospital strategic planning, and post-stroke care and rehabilitation management. Moreover, appropriate assessment of a physical activity intervention for older adults is pertinent to falls prevention and reduction of musculoskeletal disorders among sedentary seniors.Read moreRead less
Hierarchical Finite Mixture Modelling Of Health Outcomes: A Risk-adjusted Random Effects Approach
Funder
National Health and Medical Research Council
Funding Amount
$117,000.00
Summary
In medical and health studies, finite mixture regression models have been used to analyze data arising from heterogeneous populations. Traditionally, the application of mixture models is mainly concerned with finite normal mixtures. Recent computational advances and methodological developments have enhanced the extension of the method to non-normal finite mixtures, such as the modelling of discrete responses in finite mixture of generalized linear models and overlapping phases of failure time da ....In medical and health studies, finite mixture regression models have been used to analyze data arising from heterogeneous populations. Traditionally, the application of mixture models is mainly concerned with finite normal mixtures. Recent computational advances and methodological developments have enhanced the extension of the method to non-normal finite mixtures, such as the modelling of discrete responses in finite mixture of generalized linear models and overlapping phases of failure time data in the context of survival analysis. However, due to the hierarchical study design or the data collection procedure, the inherent correlation structure and-or clustering effects present may contribute to extra variations and violation of the independence assumption, resulting in spurious associations and misleading inferences based on the finite mixture model. This project aims to present a unified approach to accommodate both heterogeneity and dependency of observations, by incorporating random effects into finite mixture regression models. The new methodology will provide an integrated framework to analyze heterogeneous and correlated health outcomes. Three empirical studies are considered, namely, evaluation of an occupational injury reduction intervention, length of hospital stay modeling, and analysis of survival times of patients after cardiac surgery. The long term benefits to bioscience are accurate and valid conclusions inferred from medical and health studies, as well as the correct identification of high-risk subgroups. For the three application areas of this project, the improved analyses will specifically enable the evaluation of a participatory ergonomics intervention, the assessment of hospital efficiency and factors influencing length of hospitalization, and the determination of effectiveness of treatments prescribed pre- and post- operation, respectively.Read moreRead less
Understanding Illness Trajectories And Developing Novel Therapies For Individuals With Psychosis
Funder
National Health and Medical Research Council
Funding Amount
$640,210.00
Summary
Understanding how the psychosis impacts on the patient and family will enable better planning of services and treatment, and facilitate the introduction of new rehabilitation/therapy options for patients at first episode of psychosis and beyond.
Developing Better Models Of Outcome For Psychotic Disorders
Funder
National Health and Medical Research Council
Funding Amount
$458,695.00
Summary
Research on psychosis has been focused on developing treatments for hallucinations and delusions. However, ‘outcome’ is multifaceted and must embrace functioning, and quality of life. A/Prof Cotton will develop models will comprehensively capture ‘whole person’ outcomes for people who have experienced psychosis. Understanding how the disease impacts on the individual will enable better service planning, and refinement and development of treatments for patients with psychosis.
Impact Of Extreme Prematurity Or Extreme Low Birthweight On Young Adult Health And Well-Being: The Victorian Infant Collaborative Study (VICS) 1991-92 Longitudinal Cohort
Funder
National Health and Medical Research Council
Funding Amount
$725,496.00
Summary
Significant advances in medical care have increased survival of the tiniest and most premature babies. Those who have benefited from modern medicine are now in their mid-20s. We know they have more problems in childhood and adolescence compared with those born full term. However, we know little about their health problems in adulthood. This study will inform us of adult health problems in this vulnerable group and provide vital information about the best care for this increasing group of adults.
Reducing The Impact Of Early Life Disadvantage Via The Home Learning Environment
Funder
National Health and Medical Research Council
Funding Amount
$658,283.00
Summary
Australian children from disadvantaged families are 2-3 times more likely to be behind their peers at school entry. This project investigates the long-term effects of smalltalk, a parenting program to help parents support their children’s early development by enriching the home learning environment. We will examine the effects of smalltalk on the home environment, children’s school readiness and socio-emotional development, and assess its long-term health, education and economic benefits.
The Australia And New Zealand Fontan Registry: A Growing Population Of Young Adults With Heart Failure
Funder
National Health and Medical Research Council
Funding Amount
$129,103.00
Summary
The Fontan procedure is an operation performed for all children with heart defects who cannot be repaired with 2 pumping chambers like a normal heart. It is expected that after 2 or 3 decades, these patients will either die or need a heart transplantation. We want to establish a registry to evaluate the number and status of this increasing patient population. This study may foresee and even prevent a sudden burden on the health system caused by their needs.
Determinants Of Successfully Living With Aphasia After Stroke: A Prospective Cohort Mixed Methods Study
Funder
National Health and Medical Research Council
Funding Amount
$469,003.00
Summary
People with the communication disability of aphasia following stroke are critical of rehabilitation services. This project seeks to determine what it takes to live successfully with aphasia so that aphasia rehabilitation can be improved. Participants will be interviewed over the first 12 months following the stroke. The most important factors contributing to success will be identified and barriers and facilitators described. The most important factors can then be targeted in rehabilitation.
Towards Evidence-based Care For Rett Syndrome: A Research Model To Inform Management Of Rare Disorders
Funder
National Health and Medical Research Council
Funding Amount
$458,046.00
Summary
Rett syndrome is a rare but serious genetic neurological disorder affecting mainly girls and often complicated by spinal curvature and poor growth. This project will use national register data collected over 16 years to examine change in functional abilities and progression of the scoliosis curve. It will develop guidelines and improve processes to assist with diagnosis and will comprehensively evaluate the surgical treatments used in the management of scoliosis and growth problems.
A Population-based Longitudinal Study Of Cancer Survivors' Psychosocial And Physical Well Being
Funder
National Health and Medical Research Council
Funding Amount
$454,600.00
Summary
Cancer control is a National Health Priority Area. About 345,000 new cases of cancer are diagnosed in Australia each year. It is the second highest cause of death accounting for 27% of all deaths in Australia each year. Improvements in diagnosis and treatment have resulted in a growing number of people living with a history of cancer and for longer periods. Many cancer survivors report experiencing negative effects of cancer such as fatigue, anxiety, depression, and disrupted family and social r ....Cancer control is a National Health Priority Area. About 345,000 new cases of cancer are diagnosed in Australia each year. It is the second highest cause of death accounting for 27% of all deaths in Australia each year. Improvements in diagnosis and treatment have resulted in a growing number of people living with a history of cancer and for longer periods. Many cancer survivors report experiencing negative effects of cancer such as fatigue, anxiety, depression, and disrupted family and social relationships well after treatment has finished. Despite the large burden of this disease, little is known about the later effects that cancer and its treatment has on cancer survivors, their ongoing concerns, how the issues they face change over time and the type of support they need. This will be the first population-based longitudinal survey of the physical and psychosocial effects that cancer has on adult cancer survivors to be undertaken in Australia. It will follow cancer survivors for the first five years from diagnosis to provide data on important outcomes including anxiety, depression, quality of life and unmet needs. It will also provide the first population-based data on the predictors of these outcomes, including social support, coping style and patient demographic, treatment and disease characteristics. Given the large-scale cancer survivorship initiatives underway internationally, it is timely for high quality and comprehensive Australian data to be obtained. These data will provide new information on how the physical, social and emotional impact of cancer changes with time since diagnosis and a better understanding of the support desired by cancer survivors at various stages of recovery or disease progression. This information will help guide the development of policies and services that are tailored to the needs of Australian cancer survivors.Read moreRead less