Yuejen Zhao

Cancer incidence and survival for Indigenous Australians in the Northern Territory

Objective: To compare cancer incidence and survival for the Northern Territory (NT) Indigenous population with that of other Australians, and to assess NT Indigenous incidence time trends.

Estimating chronic disease prevalence among the remote Aboriginal population of the Northern Territory using multiple data sources.

Objective: To determine the prevalence rates of hypertension, diabetes, ischaemic heart disease (IHD), renal disease and chronic obstructive pulmonary disease (COPD), and their co‐occurrence among the remote Aboriginal population of the Northern Territory (NT) in 2005.

Decomposing Indigenous life expectancy gap by risk factors: a life table analysis

BackgroundThe estimated gap in life expectancy (LE) between Indigenous and non-Indigenous Australians was 12 years for men and 10 years for women, whereas the Northern Territory Indigenous LE gap was at least 50% greater than the national figures. This study aims to explain the Indigenous LE gap by common modifiable risk factors.MethodsThis study covered the period from 1986 to 2005. Unit record death data from the Northern Territory were used to assess the differences in LE at birth between the Indigenous and non-Indigenous populations by socioeconomic disadvantage, smoking, alcohol abuse, obesity, pollution, and intimate partner violence. The population attributable fractions were applied to estimate the numbers of deaths associated with the selected risks. The standard life table and cause decomposition technique was used to examine the individual and joint effects on health inequality.ResultsThe findings from this study indicate that among the selected risk factors, socioeconomic disadvantage was the leading health risk and accounted for one-third to one-half of the Indigenous LE gap. A combination of all six selected risks explained over 60% of the Indigenous LE gap.ConclusionsImproving socioeconomic status, smoking cessation, and overweight reduction are critical to closing the Indigenous LE gap. This paper presents a useful way to explain the impact of risk factors of health inequalities, and suggests that reducing poverty should be placed squarely at the centre of the strategies to close the Indigenous LE gap.

A cost-consequences analysis of a Midwifery Group Practice for Aboriginal mothers and infants in the Top End of the Northern Territory, Australia

OBJECTIVE to compare the cost-effectiveness of two models of service delivery: Midwifery Group Practice (MGP) and baseline cohort. DESIGN a retrospective and prospective cohort study. SETTING a regional hospital in Northern Territory (NT), Australia. METHODS baseline cohort included all Aboriginal mothers (n=412), and their infants (n=416), from two remote communities who gave birth between 2004 and 2006. The MGP cohort included all Aboriginal mothers (n=310), and their infants (n=315), from seven communities who gave birth between 2009 and 2011. The baseline cohort mothers and infants medical records were retrospectively audited and the MGP cohort data were prospectively collected. All the direct costs, from the Department of Health (DH) perspective, occurred from the first antenatal presentation to six weeks post partum for mothers and up to 28 days post births for infants were included for analysis. ANALYSIS analysis was performed with SPSS 19.0 and Stata 12.1. Independent sample of t-tests and χ2 were conducted. FINDINGS women receiving MGP care had significantly more antenatal care, more ultrasounds, were more likely to be admitted to hospital antenatally, and had more postnatal care in town. The MGP cohort had significantly reduced average length of stay for infants admitted to Special Care Nursery (SCN). There was no significant difference between the two cohorts for major birth outcomes such as mode of birth, preterm birth rate and low birth weight. Costs savings (mean A

Theory and Methods: Influence Diagnostics for Simultaneous Equations Models

703) were found, although these were not statistically significant, for women and their infants receiving MGP care compared to the baseline cohort. CONCLUSIONS for remote dwelling Aboriginal women of all risk who travelled to town for birth, MGP was likely to be cost effective, and women received better care and resulting in equivalent birth outcomes compared with the baseline maternity care.

Dementia prevalence and incidence among the Indigenous and non-Indigenous populations of the Northern Territory.

This paper presents influence diagnostics for simultaneous equations models. It proposes residuals, leverage and other influence measures. A missing data method is adopted to minimize the masking effect due to case deletions. The assessment of local influence is also considered. The paper shows how to evaluate the effects that perturbations to the endogenous variables, predetermined variables and case weights may have on the parameter estimates. The diagnostics are illustrated with two examples.

A discordancy test approach to identify outliers of length of hospital stay

Objective: To estimate the prevalence and incidence of dementia in Northern Territory Indigenous and non‐Indigenous populations.

A multilevel analysis on the relationship between neighbourhood poverty and public hospital utilization: is the high Indigenous morbidity avoidable?

A discordancy test approach is proposed to identify outliers of inpatient length of stay. This has implications not only for benchmarking service delivery but also for linking budget allocation procedures to efficiency of health service provisions. The effects of shifting trim point thresholds on hospital payments are assessed in a case study of a group of obstetrical patients.

Sensitivity of pearson's goodness-of-fit statistic in generalized linear models

BackgroundThe estimated life expectancy at birth for Indigenous Australians is 10-11 years less than the general Australian population. The mean family income for Indigenous people is also significantly lower than for non-Indigenous people. In this paper we examine poverty or socioeconomic disadvantage as an explanation for the Indigenous health gap in hospital morbidity in Australia.MethodsWe utilised a cross-sectional and ecological design using the Northern Territory public hospitalisation data from 1 July 2004 to 30 June 2008 and socio-economic indexes for areas (SEIFA) from the 2006 census. Multilevel logistic regression models were used to estimate odds ratios and confidence intervals. Both total and potentially avoidable hospitalisations were investigated.ResultsThis study indicated that lifting SEIFA scores for family income and education/occupation by two quintile categories for low socio-economic Indigenous groups was sufficient to overcome the excess hospital utilisation among the Indigenous population compared with the non-Indigenous population. The results support a reframing of the Indigenous health gap as being a consequence of poverty and not simplistically of ethnicity.ConclusionsSocio-economic disadvantage is a likely explanation for a substantial proportion of the hospital morbidity gap between Indigenous and non-Indigenous populations. Efforts to improve Indigenous health outcomes should recognise poverty as an underlying determinant of the health gap.

Influence diagnostics for generalized linear measurement error models.

This paper investigates the local influence estimation of the-goodness-of-fit sia,listic in generalized linear model settings. Inspired by Cook (1986), a loral influence approach is adopted to assess model adequacy with respert to the contours uf the unperturbed generalized Pearsons statistic. Based on local perturbations to the vectors of case weights, covariates and responses, the approach can detect different aspects of influence and yield additional insight to likelihood displacement Two examples demonstrate the effectiveness of the proposed method.