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You searched for +publisher:"University of Adelaide" +contributor:("Salter, Amy Beatrix"). Showing records 1 – 3 of 3 total matches.

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University of Adelaide

1. Yelland, Lisa Nicole. Statistical issues associated with the analysis of binary outcomes in randomised controlled trials when the effect measure of interest is the relative risk.

Degree: 2011, University of Adelaide

Background: Binary outcomes have traditionally been analysed using logistic regression which estimates odds ratios. A popular alternative is to estimate relative risks using log binomial regression. Due to convergence problems with this model, alternative methods have been proposed for estimating relative risks. Comparisons between methods are limited and guidance on which method(s) should be used in practice is lacking. These methods are often applied to clustered data, despite the absence of evidence supporting their use in this setting. Comparison of methods in the clustered data setting via simulation is difficult. The simulation model requires specification of the random effects variance on the log scale, but the intraclass correlation coefficient (ICC) on the probability scale is the preferred measure of dependence. The relationship between the ICC and the random effects variance has been defined under the logistic model but not the log binomial model. The appropriate method for analysing binary outcomes from perinatal trials which include infants from multiple births is a matter of debate, and relative risks have received little attention in this context. Aim: To investigate statistical issues associated with the analysis of binary outcomes in randomised controlled trials (RCTs) when the effect measure of interest is the relative risk. Specifically, the aims are: • To compare the performance of methods for estimating relative risks in RCTs with independent and clustered observations; • To determine the relationship between the ICC on the probability scale and the between cluster variance on the log scale; • To provide guidance on the analysis of binary outcomes from perinatal trials including infants from multiple births. Methods: Simulation studies are conducted to compare methods for estimating relative risks using independent and clustered data. To determine the ICC in the latter scenario, the relationship between the ICC on the probability scale and the random effects variance on the log scale is derived. Additional simulation studies are conducted to determine how different analytical methods compare in perinatal trials with multiple births. Example datasets are analysed for illustration. Results: Some methods for estimating relative risks are associated with large bias and poor coverage. Others fail to overcome the convergence problems of log binomial regression. Several methods perform well across a wide range of independent and clustered data settings, including modified Poisson regression. When simulating clustered data, the ICC can be determined from the random effects variance on the log scale based on a Taylor series expansion or properties of the lognormal distribution. Failure to account for clustering in perinatal trials including multiple births leads to inflated type I errors and undercoverage, unless both the ICC and the multiple birth rate are low. Conclusion: Relative risks are a useful measure of effect for binary outcomes. Difficulties in estimating relative risks due to convergence… Advisors/Committee Members: Ryan, Philip (advisor), Salter, Amy Beatrix (advisor), School of Population Health and Clinical Practice (school).

Subjects/Keywords: statistics; binary outcome; relative risk; randomised trial; clustered data

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Yelland, L. N. (2011). Statistical issues associated with the analysis of binary outcomes in randomised controlled trials when the effect measure of interest is the relative risk. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/74129

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Yelland, Lisa Nicole. “Statistical issues associated with the analysis of binary outcomes in randomised controlled trials when the effect measure of interest is the relative risk.” 2011. Thesis, University of Adelaide. Accessed January 18, 2020. http://hdl.handle.net/2440/74129.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Yelland, Lisa Nicole. “Statistical issues associated with the analysis of binary outcomes in randomised controlled trials when the effect measure of interest is the relative risk.” 2011. Web. 18 Jan 2020.

Vancouver:

Yelland LN. Statistical issues associated with the analysis of binary outcomes in randomised controlled trials when the effect measure of interest is the relative risk. [Internet] [Thesis]. University of Adelaide; 2011. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/2440/74129.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Yelland LN. Statistical issues associated with the analysis of binary outcomes in randomised controlled trials when the effect measure of interest is the relative risk. [Thesis]. University of Adelaide; 2011. Available from: http://hdl.handle.net/2440/74129

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


University of Adelaide

2. Gillam, Marianne Knarberg Hansen. Time to event analysis of arthroplasty registry data.

Degree: 2013, University of Adelaide

Background: Arthroplasty registry data are traditionally analysed using standard survival methods, that is, Kaplan-Meier survival curves and the Cox proportional hazards model. The outcome of interest is usually the time from the primary procedure until occurrence of a single event – revision of the prosthesis. Other outcomes may also be of interest, for example, time to death, time to receiving another arthroplasty and the association between covariates and these events. The rise in life expectancy of the population combined with an increasing number of joint replacements being performed has resulted in many patients experiencing several joint replacement procedures during their lifetime. The analyses of registry data such as these require the use of more sophisticated statistical methods. Application and evaluation of statistical methods to analyse registry data containing complex arthroplasty histories are lacking. Aim: The aim of this thesis was to investigate the use of statistical methods in the analysis of multiple event data contained in arthroplasty registries. Within this broad aim the objectives were to investigate the use of competing risks methods in estimating the risk and rate of revision, investigate methods for handling covariates with time-varying effect, investigate the use of multi-state modelling techniques in providing a more comprehensive analysis and description of complex arthroplasty histories than traditional survival methods and to develop a notation system to facilitate the description and analysis of arthroplasty event history data. Methods: Data were obtained from the Australian Orthopaedic Association National Joint Replacement Registry and the Norwegian Arthroplasty Register. Estimates of revision from the Kaplan-Meier method were compared to estimates from the cumulative incidence function which accounts for the competing risk of death. Effects of covariates on the rate and risk of revision were estimated with competing risk regression and compared to estimates from the Cox proportional hazards model. Multi-state models were set up and applied to the data. The Summary Notation for Arthroplasty Histories (SNAH) was developed in order to help manage and analyse this type of data. Results: The Kaplan-Meier method substantially overestimated the risk of revision compared to estimates using competing risks methods when the incidence of the competing risk of death was high. The influence of some covariates on the hazard rate was different to the influence on the actual probability of occurrence of the event as this was modulated by their relationship with the competing event. Multi-state models, in combination with SNAH codes, were well suited to the management and analysis of arthroplasty registry data on patients who had multiple joint procedures over time. Multi-state modelling techniques proved useful in the investigation of the progression of end-stage osteoarthritis in data from two national arthroplasty registries. Conclusion: In the presence of competing risks, the Kaplan-Meier… Advisors/Committee Members: Ryan, Philip (advisor), Salter, Amy Beatrix (advisor), School of Population Health (school).

Subjects/Keywords: arthroplasty; hip; knee; statistical analysis; multi-state models; registry data

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Gillam, M. K. H. (2013). Time to event analysis of arthroplasty registry data. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/82454

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Gillam, Marianne Knarberg Hansen. “Time to event analysis of arthroplasty registry data.” 2013. Thesis, University of Adelaide. Accessed January 18, 2020. http://hdl.handle.net/2440/82454.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Gillam, Marianne Knarberg Hansen. “Time to event analysis of arthroplasty registry data.” 2013. Web. 18 Jan 2020.

Vancouver:

Gillam MKH. Time to event analysis of arthroplasty registry data. [Internet] [Thesis]. University of Adelaide; 2013. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/2440/82454.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Gillam MKH. Time to event analysis of arthroplasty registry data. [Thesis]. University of Adelaide; 2013. Available from: http://hdl.handle.net/2440/82454

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

3. AlMarzooqi, Mazna Abdulrahman. Physical activity among young educated Saudi women.

Degree: 2018, University of Adelaide

Physical inactivity is an important risk factor for the long term health of young people. Health risk behaviours established during youth often persist into adulthood, resulting in potentially harmful effects on long-term health. Although research on physical activity in Saudi Arabia is limited, the few available studies reveal high rates of physical inactivity, especially among youth and women. Hence, there is an urgent need to understand the factors that may shape engagement of young Saudi women in physical activity in Saudi Arabia. This study uses the Social Ecological Model of physical activity to analyse the effects of multiple factors (individual, social environment, physical environment, and policy) on physical activity behaviour among young educated Saudi women (YESW). A sample of YESW aged between 18 and 24 years old currently enrolled as undergraduate students in the Faculty of Health Sciences at one University in Riyadh, Saudi Arabia were recruited. The study used a combination of in-depth interviews, focus groups and self-reported surveys to explore YESW’s understanding of physical activity and the factors that affect their engagement in it. The findings highlight a range of individual, environmental and policy barriers to physical activity behaviour among YESW. In addition, findings show how gender influences these factors and shapes physical activity behaviour. Potential intervention strategies include empowering young women in decision making, raising family and male guardians’ support for physical activity, and increasing affordable and accessible physical activity options at individual and environmental levels. Advisors/Committee Members: Braunack-Mayer, Annette Joy (advisor), Xafis, Vicki (advisor), Salter, Amy Beatrix (advisor), Mahmmod, Afzal (advisor), Gawwad, Ensaf (advisor), School of Public Health (school).

Subjects/Keywords: physical activity; walking behaviour; social determinants of health; women's health

…institution without the prior approval of the University of Adelaide and where applicable, any… …support and help are much appreciated. Next, I would like to thank the University of Adelaide… 

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

AlMarzooqi, M. A. (2018). Physical activity among young educated Saudi women. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/114427

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

AlMarzooqi, Mazna Abdulrahman. “Physical activity among young educated Saudi women.” 2018. Thesis, University of Adelaide. Accessed January 18, 2020. http://hdl.handle.net/2440/114427.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

AlMarzooqi, Mazna Abdulrahman. “Physical activity among young educated Saudi women.” 2018. Web. 18 Jan 2020.

Vancouver:

AlMarzooqi MA. Physical activity among young educated Saudi women. [Internet] [Thesis]. University of Adelaide; 2018. [cited 2020 Jan 18]. Available from: http://hdl.handle.net/2440/114427.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

AlMarzooqi MA. Physical activity among young educated Saudi women. [Thesis]. University of Adelaide; 2018. Available from: http://hdl.handle.net/2440/114427

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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