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
Ear Health, Hearing, Speech And Language Development In Urban Aboriginal Children
Funder
National Health and Medical Research Council
Funding Amount
$445,617.00
Summary
Studies from the Northern Territory and Western Australia have established that Aboriginal children experience earlier, more frequent and more severe middle ear disease than any other children worldwide. There is little information on Aboriginal communities in urban setings or those living in NSW. This study will fill this knowledge gap by examining the burden of middle ear disease, hearing impairment and consequent speech and language delays in urban Aboriginal children in NSW.
Limiting Weight Gain In Overweight And Obese Women During Pregnancy To Improve Health Outcomes - A Randomised Trial.
Funder
National Health and Medical Research Council
Funding Amount
$1,541,444.00
Summary
Being overweight or obese is a major health issue for women during pregnancy and childbirth in Australia. There are well documented risks associated with obesity during pregnancy for both the mother and her baby. This randomised trial will assess whether the implementation of a package of dietary and lifestyle advice to overweight and obese pregnancy women to limit weight gain during pregnancy is effective in improving health outcomes for women and their babies.
Adolescent Population Health: Application Of Best-Worst Scaling Discrete Choice Experiments To Value Health States For Use In Economic Evaluation
Funder
National Health and Medical Research Council
Funding Amount
$178,779.00
Summary
Historically, economic evaluations of health care treatment and preventive programs developed for adolescents have failed to incorporate adolescent values about their preferred health outcomes. This project will apply a novel approach known as Best-Worst Scaling to ascertain adolescent specific values for health states for incorporation into economic evaluation, thereby enabling the views of adolescents to be incorporated directly into the health care priorities decision-making process.
PSA Testing: A Population-based Longitudinal Study Of Decision Making, Psychological Effects And Patterns Of Care
Funder
National Health and Medical Research Council
Funding Amount
$576,977.00
Summary
Prostate cancer is the most commonly diagnosed cancer in Australian men and the second most common cancer- related cause of death. Since being introduced into Australia in 1988 the Prostate Specific Antigen (PSA) blood test has been widely adopted as a method for detecting early-stage asymptomatic prostate cancer. However there is controversy about the potential benefits and harms of testing for prostate cancer. Little has been documented in Australia about the information men receive when consi ....Prostate cancer is the most commonly diagnosed cancer in Australian men and the second most common cancer- related cause of death. Since being introduced into Australia in 1988 the Prostate Specific Antigen (PSA) blood test has been widely adopted as a method for detecting early-stage asymptomatic prostate cancer. However there is controversy about the potential benefits and harms of testing for prostate cancer. Little has been documented in Australia about the information men receive when considering a PSA test, what happens to men after having an abnormal PSA test and the consequences of PSA testing (including physical and psychological effects). The aim of this study is to interview a representative community sample of men aged 50 to 84 years and resident in NSW to describe: (1) the decision-making process regarding PSA testing; (2) the psychological consequences of men's PSA testing experiences; and (3) patterns of care for men who have had an abnormal PSA test. The main outcomes from this study will include substantial information on the experiences of men regarding patterns of PSA participation (frequency of, and reasons for, testing), the clinical management of men who have had an abnormal PSA test, the psychological effects of PSA testing (both positive and negative) and how decisions about testing are being made. This will provide important information to assist GPs, urologists and Australian men make decisions about PSA testing. It will highlight areas of need regarding the information required by men for informed decision-making and the support they require when undergoing PSA testing to ensure positive psychological outcomes.Read moreRead less