What birthweight percentile is associated with optimal perinatal mortality and childhood education outcomes?

BACKGROUND: Small for gestational age, defined as birthweight <10th percentile for gestational age, is known to be associated with clinically meaningful impairments in health and development. The effects of variation within the normal range of birthweight percentile on perinatal mortality and childhood education remain less well defined. OBJECTIVE: We sought to quantify the association among birthweight percentile, perinatal mortality, and educational outcomes and to determine the optimal birthweight percentile for those outcomes in Aboriginal and non-Aboriginal Australian children. STUDY DESIGN: This was a retrospective cohort study. Perinatal data for all children born in the Northern Territory, Australia, from 1999 through 2008 were linked to measures of educational attainment at age 8-9 years. Multivariable analysis was used to determine the optimal birthweight percentile for low perinatal mortality and high reading and numeracy scores. RESULTS: The birth cohort contained 35,239 births (42% Aboriginal), of which 11,214 had linked and valid education records. Median birthweight percentile was 29.2 in Aboriginal infants and 44.0 in non-Aboriginal infants. The odds of perinatal mortality decreased by 4% with each 1-percentile increase birthweight percentile overall (adjusted odds ratio, 0.96; P = .000) and lowest mortality rates were at the 61st and 78th percentile in Aboriginal and non-Aboriginal infants, respectively. Although birthweights <10th percentile were associated with greatly increased odds of perinatal mortality, the increased risk extended well beyond this cut-off. Birthweight percentile was also positively correlated with scores in reading (P = .000) and numeracy (P = .000). In non-Aboriginal children, reading and numeracy scores peaked at the 66th percentile, but for Aboriginal children there was continuous benefit with increasing birthweight percentile. Birthweight percentile explained 1% of the variation in education outcomes, with much greater variation explained by other perinatal and sociodemographic factors. CONCLUSION: Birthweights between the 50th-93rd percentiles were most consistently associated with both low perinatal mortality and high reading and numeracy scores, suggesting that small for gestational age does not sufficiently capture the risks associated with variation in fetal growth. Our data indicate that the effect of birthweight percentile accounts for 1% of variation in perinatal and education outcomes.

Progress in closing the gap in life expectancy at birth for Aboriginal people in the Northern Territory, 1967-2012.

OBJECTIVES: To compare long term changes in mortality and life expectancy at birth (LE) of Aboriginal people in the Northern Territory and of the overall Australian population; to determine the contributions of changes in mortality in specific age groups to changes in LE for each population. DESIGN, SETTING, PARTICIPANTS: Retrospective trend analysis of death and LE data for the NT Aboriginal and Australian populations, 1967-2012. MAIN OUTCOME MEASURES: LE estimates based on abridged life tables; mortality estimates (deaths per 100 000 population); and age decomposition of LE changes by sex and time period. RESULTS: Between 1967 and 2012, LE increased for both NT Aboriginal and all Australians; the difference in LE between the two populations declined by 4.6 years for females, but increased by one year for males. Between 1967-1971 and 1980-1984, LE of NT Aboriginal people increased rapidly, particularly through reduced infant mortality; from 1980-1984 to 1994-1998, there was little change; from 1994-1998 to 2008-2012, there were modest gains in older age groups. Decomposition by age group identified the persistent and substantial contribution of the 35-74-year age groups to the difference in LE between NT Aboriginal people and all Australians. CONCLUSIONS: Early gains in LE for NT Aboriginal people are consistent with improvements in nutrition, maternal and infant care, and infectious disease control. A rapid epidemiological transition followed, when LE gains in younger age groups plateaued and non-communicable diseases became more prevalent. Recent LE gains, across all adult age groups, are consistent with improved health service access and chronic disease management. If LE is to continue improving, socio-economic disadvantage and its associated risks must be reduced.

Frequent use of hospital inpatient services during a nine year period: a retrospective cohort study.

BACKGROUND: Frequent use (FU) of hospital services impacts on patients and health service expenditure. Studies examining FU in emergency departments and inpatient settings have found heterogeneity and the need to differentiate between potentially preventable FU and that associated with ongoing management of complex conditions. Psychosocial factors have often been reported as underpinning or exacerbating the phenomena. Most FU studies have been limited by time, to a single study site, or restricted to specific diagnoses or patient groups. This study provides a comprehensive description of adult patient characteristics, conditions and risk factors associated with FU, based on admissions to the five public hospitals in the Northern Territory (NT) of Australia over a nine year period. The study population is distinctive comprising both Aboriginal and non-Aboriginal patients. METHODS: Data on all inpatient episodes in NT public hospitals between 2005 and 2013 was analysed to identify patients with any FU (four or more episodes within any 12-month period) and measure FU duration (number of FU years) and intensity (mean number of episodes per FU year). Pregnancy, alcohol-related and mental health condition flags were assigned to patients with any episode with relevant diagnoses during the study period. Multivariate analysis was used to assess factors associated with any FU, FU duration and FU intensity, separately for Aboriginal and non-Aboriginal patients. RESULTS: Of people with any inpatient episodes during the study period, 13.6% were frequent users (Aboriginal 22%, non-Aboriginal 10%) accounting for 46.6% of all episodes. 73% of frequent users had only one FU year. Any FU and increased FU duration were more common among individuals who were: Aboriginal; older; female; and those with a pregnancy, alcohol or mental health flag. Having two or more alcohol-related episodes in the nine-year period was strongly associated with any FU for both Aboriginal (odds ratio 8.9, 95% CI. 8.20-9.66) and non-Aboriginal patients (11.5, 9.92-13.26). CONCLUSION: For many people, frequent inpatient treatment is necessary and unavoidable. This study suggests that damage arising from excessive alcohol consumption (either personal or by others) is the single most avoidable factor associated with FU, particularly for Aboriginal people.

Stroke incidence and case-fatality among Indigenous and non-Indigenous populations in the Northern Territory of Australia, 1999-2011.

BACKGROUND: Stroke is a leading cause of death and disability in Australia. The impact of stroke on the Australia Indigenous people is, however, unclear. AIM: This study describes hospital-based stroke incidence and case fatality in the Northern Territory population in Australia. METHODS: Retrospective study of Northern Territory residents with a first-ever stroke episode and case fatality among Northern Territory residents in 1999-2011. RESULTS: The rate ratio of age-adjusted stroke incidence between Indigenous and non-Indigenous populations was 2·8 for men and 2·7 for women, similar to those reported elsewhere in Australia. The rate ratio increased to 3·8 (95% confidence interval: 3·4-4·3) after adjusting for multiple risk factors. There was no change in annual incidence between 1999 and 2011 for either non-Indigenous (incidence rate ratio per year 1·01, 95% confidence interval: 1·00-1·03) or Indigenous people (incidence rate ratio: 1·00, 95% confidence interval: 0·98-1·02), although incidence did increase for non-Indigenous people in the 15-39 year age group (incidence rate ratio: 1·09, 95% confidence interval: 1·02-1·17) and for Indigenous people in the 40-64 year age group (incidence rate ratio: 1·03, 95% confidence interva1·00-1·06). The case fatality rate decreased from 22% in 1999 to 12% in 2011. In-hospital deaths were more common among; older and Indigenous people, for those with other chronic diseases, and from haemorrhagic stroke compared with ischemic stroke. CONCLUSIONS: In the Northern Territory, as elsewhere in Australia, Indigenous Australians are more likely than other Australians to suffer a stroke. Lack of falling in incidence in the Northern Territory population highlights the importance for ongoing comprehensive primary and acute care in reducing risk factors and managing stroke patients.

Better health outcomes at lower costs: the benefits of primary care utilisation for chronic disease management in remote Indigenous communities in Australia's Northern Territory.

BACKGROUND: Indigenous residents living in remote communities in Australia's Northern Territory experience higher rates of preventable chronic disease and have poorer access to appropriate health services compared to other Australians. This study compared health outcomes and costs at different levels of primary care utilisation to determine if primary care represents an efficient use of resources for Indigenous patients with common chronic diseases namely hypertension, diabetes, ischaemic heart disease, chronic obstructive pulmonary disease and renal disease. METHODS: This was an historical cohort study involving a total of 14,184 Indigenous residents, aged 15 years and over, who lived in remote communities and used a remote clinic or public hospital from 2002 to 2011. Individual level demographic and clinical data were drawn from primary care and hospital care information systems using a unique patient identifier. A propensity score was used to improve comparability between high, medium and low primary care utilisation groups. Incremental cost-effectiveness ratios and acceptability curves were used to analyse four health outcome measures: total and, avoidable hospital admissions, deaths and years of life lost. RESULTS: Compared to the low utilisation group, medium and high levels of primary care utilisation were associated with decreases in total and avoidable hospitalisations, deaths and years of life lost. Higher levels of primary care utilisation for renal disease reduced avoidable hospitalisations by 82-85%, deaths 72-75%, and years of life lost 78-81%. For patients with ischaemic heart disease, the reduction in avoidable hospitalisations was 63-78%, deaths 63-66% and years of life lost 69-73%. In terms of cost-effectiveness, primary care for renal disease and diabetes ranked as more cost-effective, followed by hypertension and ischaemic heart disease. Primary care for chronic obstructive pulmonary disease was the least cost-effective of the five conditions. CONCLUSION: Primary care in remote Indigenous communities was shown to be associated with cost-savings to public hospitals and health benefits to individual patients. Investing $1 in primary care in remote Indigenous communities could save $3.95-$11.75 in hospital costs, in addition to health benefits for individual patients. These findings may have wider applicability in strengthening primary care in the face of high chronic disease prevalence globally.

Trends in hospital admissions for conditions associated with child maltreatment, Northern Territory, 1999-2010.

OBJECTIVE: To use hospital admissions data to investigate trends in maltreatment among Northern Territory Aboriginal and non-Aboriginal children. DESIGN, SETTING AND PARTICIPANTS: A historical cohort study using diagnosis and external cause codes from hospital admissions among children aged 0-17 years. MAIN OUTCOME MEASURES: Annual rates of admission with either a definitive or indicative code for child maltreatment. RESULTS: From 1 January 1999 to 31 December 2010, the average annual rates of hospital admission of NT Aboriginal and non-Aboriginal children with a definitive code of maltreatment were 8.8 (95% CI, 7.4-10.2) and 0.91 (95% CI, 0.59-1.22) per 10 000 children, respectively. There was no evidence for change over time in either population. The corresponding rates of admission with a code indicative of maltreatment were 28.4 (95% CI, 25.8-31.1) and 5.2 (95% CI, 4.4-6.0) per 10 000 children, with average annual increases of 3% (incidence rate ratio [IRR], 1.03; 95% CI, 1.00-1.07) and 4% (IRR, 1.04; 95% CI, 0.96-1.11). Physical abuse was the prominent type of maltreatment-related admission in both populations. There were increases in rates of admission for older Aboriginal children (13-17 years) and older non-Aboriginal boys. Most perpetrators in the assault of younger children were family members, while among older children most were not specified. CONCLUSION: Our study shows the utility of hospital admissions for population surveillance of child maltreatment. The relatively stable rate of maltreatment-related hospital admissions among NT Aboriginal children shown here is in contrast to substantial increases reported from child protection data. The results also highlight the overlap between violence within families and in the wider community, particularly for older children, and lends support for population-level interventions to protect vulnerable children.

The cost-effectiveness of primary care for Indigenous Australians with diabetes living in remote Northern Territory communities.

OBJECTIVE: To evaluate the costs and health outcomes associated with primary care use by Indigenous people with diabetes in remote communities in the Northern Territory. DESIGN, SETTING AND PARTICIPANTS: A population-based retrospective cohort study from 1 January 2002 to 31 December 2011 among Indigenous NT residents ≥ 15 years of age with diabetes who attended one of five hospitals or 54 remote clinics in the NT. MAIN OUTCOME MEASURES: Hospitalisations, potentially avoidable hospitalisations (PAH), mortality and years of life lost (YLL). Variables included disease stage (new, established or complicated cases) and primary care use (low, medium or high). RESULTS: 14 184 patients were eligible for inclusion in the study. Compared with the low primary care use group, the medium-use group (patients who used primary care 2-11 times annually) had lower rates of hospitalisation, lower PAH, lower death rates and fewer YLL. Among complicated cases, this group showed a significantly lower mean annual hospitalisation rate (1.2 v 6.7 per person [P < 0.001]) and PAH rate (0.72 v 3.64 per person [P < 0.001]). Death rate and YLL were also significantly lower (1.25 v 3.77 per 100 population [P < 0.001] and 0.29 v 1.14 per person-year [P < 0.001], respectively). The cost of preventing one hospitalisation for diabetes was $248 for those in the medium-use group and $739 for those in the high-use group. This compares to $2915, the average cost of one hospitalisation. CONCLUSION: Improving access to primary care in remote communities for the management of diabetes results in net health benefits to patients and cost savings to government.

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

OBJECTIVE: To estimate the prevalence and incidence of dementia in Northern Territory Indigenous and non-Indigenous populations. DESIGN, SETTING AND PARTICIPANTS: Four data sources were used to identify clients with a diagnosis of dementia, from 1 January 2008 to 31 December 2011. The data sources included hospital admissions, aged care services, primary care and death registration. A capture-recapture method was used to estimate prevalence and incidence, including both diagnosed and unknown cases. MAIN OUTCOME MEASURES: Prevalence and incidence of dementia among the NT Indigenous and non-Indigenous populations. RESULTS: In 2011, the estimated prevalence in the NT Indigenous population aged 45 years and over was 3.7 per 100, and 1.1 per 100 in the corresponding NT non-Indigenous population. The age-adjusted prevalence for the NT Indigenous population was 6.5 per 100, compared with the NT non-Indigenous prevalence of 2.6 per 100, which was similar to the national rate. The prevalence rate ratios of NT Indigenous to NT non-Indigenous men and women, respectively, were: 6.5 and 5.5 for the 45-64-years age group, 4.0 and 4.1 for those aged 65-74 years and 2.1 and 1.9 for those aged 75 years and over. The age-adjusted incidence among the NT Indigenous population aged 45 years and over (27.3 per 1000 person-years) was higher than that among the NT non-Indigenous population (10.7 per 1000 person-years). CONCLUSION: The NT Indigenous population has a much higher prevalence and incidence of dementia and younger onset of disease compared with their non-Indigenous counterparts. The results highlight the urgent need for interventions to moderate the emerging impact of dementia in the Australian Indigenous population.

Health inequity in the Northern Territory, Australia.

INTRODUCTION: Understanding health inequity is necessary for addressing the disparities in health outcomes in many populations, including the health gap between Indigenous and non-Indigenous Australians. This report investigates the links between Indigenous health outcomes and socioeconomic disadvantage in the Northern Territory of Australia (NT). METHODS: Data sources include deaths, public hospital admissions between 2005 and 2007, and Socio-Economic Indexes for Areas from the 2006 Census. Age-sex standardisation, standardised rate ratio, concentration index and Poisson regression model are used for statistical analysis. RESULTS: There was a strong inverse association between socioeconomic status (SES) and both mortality and morbidity rates. Mortality and morbidity rates in the low SES group were approximately twice those in the medium SES group, which were, in turn, 50% higher than those in the high SES group. The gradient was present for most disease categories for both deaths and hospital admissions. Residents in remote and very remote areas experienced higher mortality and hospital morbidity than non-remote areas. Approximately 25-30% of the NT Indigenous health disparity may be explained by socioeconomic disadvantage. CONCLUSIONS: Socioeconomic disadvantage is a shared common denominator for the main causes of deaths and principal diagnoses of hospitalisations for the NT population. Closing the gap in health outcomes between Indigenous and non-Indigenous populations will require improving the socioeconomic conditions of Indigenous Australians.

Trends in reports of child maltreatment in the Northern Territory, 1999-2010.

OBJECTIVE: To examine trends in reports of child maltreatment to the Northern Territory Department of Children and Families among Aboriginal and non-Aboriginal children. DESIGN, SETTING AND SUBJECTS: A historical cohort study using administrative data collections of notifications and substantiated cases of maltreatment among children aged from 0 to 17 years. MAIN OUTCOME MEASURES: Annual rates of notification and substantiation of different types of child maltreatment. RESULTS: From 1999 to 2010, the overall annual rates of notification for maltreatment of Aboriginal children showed an average increase of 21% (incidence rate ratio [IRR], 1.21; 95% CI, 1.19-1.24). The greatest increases were in notifications for neglect and emotional abuse. There were parallel increases in rates of substantiated cases of maltreatment. Among non-Aboriginal children, the overall annual rates of notification also increased (IRR, 1.10; 95% CI, 1.07-1.14); however, changes in annual rates of substantiated cases for all types of maltreatment were not statistically significant. CONCLUSION: There have been considerable increases in both notifications and substantiated cases of child maltreatment, most prominently among Aboriginal children. It is possible that the observed increases reflect increasing incidence of maltreatment; however, they are also consistent with a mix of increased surveillance, improved service access, changes in policy and a shift in public attitudes.

Trends in alcohol-attributable hospitalisation in the Northern Territory, 1998-99 to 2008-09.

OBJECTIVE: To examine trends in hospitalisation for alcohol-attributable conditions in the Northern Territory Aboriginal and non-Aboriginal populations between the financial years 1998-99 and 2008-09. DESIGN AND SETTING: Retrospective descriptive analysis of inpatient discharge data from NT public hospitals. MAIN OUTCOME MEASURES: Alcohol-attributable hospitalisation by age, sex, Aboriginality, region of residence and medical conditions, with annual time trends. RESULTS: Annual rates of hospitalisation for alcohol-attributable conditions across the NT increased from 291.3 per 10,000 population to 460.0 per 10,000 (57.9%) among Aboriginal males and from 181.8 per 10,000 to 387.4 per 10,000 (113.1%) among Aboriginal females over the study period. The alcohol-attributable hospitalisation rate also increased from 58.8 per 10,000 population to 87.4 per 10,000 (48.6%) among non-Aboriginal males and from 16.8 per 10,000 to 37.2 per 10,000 (121.4%) among non-Aboriginal females. Alcohol-attributable hospitalisation rates among Aboriginal people living in Central Australia were much higher than in the Top End. In Central Australia, the rates for Aboriginal females increased throughout the study period, but for Aboriginal males declined from 2004-05 onwards. CONCLUSION: Rates of hospitalisation for alcohol-attributable conditions were high among NT Aboriginal people and increased during the study period. Although not statistically significant, the moderation in rates among Central Australian Aboriginal males after 2004-05 is encouraging. This apparent improvement is consistent with another recent study and provides tentative support that recent policy changes and interventions may be having an impact. The results of this study highlight the burden of alcohol use in the NT and emphasise the need for ongoing investment in comprehensive alcohol-management programs.

Trend analysis of hospital admissions attributable to tobacco smoking, Northern Territory Aboriginal and non-Aboriginal populations, 1998 to 2009.

BACKGROUND: Tobacco smoking is a well-recognised risk factor for many diseases [1]. This study assesses the extent of smoking-attributable hospitalisation in the Northern Territory (NT) Aboriginal and non-Aboriginal populations, and examines smoking-attributable hospitalisation trends for the years 1998/99 to 2008/09. METHODS: Hospital discharge data were used for the analysis. The proportion of conditions attributable to tobacco smoking was calculated using the aetiological fraction method. Age-adjusted smoking-attributable hospitalisation rates were calculated to describe the impact of tobacco smoking on the health of Territorians. A negative binominal regression model was applied to examine trends in smoking-attributable hospitalisations. RESULTS: Aboriginal Territorians were found to have higher rates of smoking-attributable hospitalisation, with Aboriginal males more than three times and Aboriginal females more than four times more likely to be hospitalised for smoking-attributable conditions than their non-Aboriginal counterparts. The age-adjusted hospitalisation rate for Aboriginal males increased by 31% and for Aboriginal females by 18% during the study period. There were more modest increases for NT non-Aboriginal males and females (5% and 17% respectively). The increase among Aboriginal males occurred up until 2005/06 followed by moderation in the trend. There were small reductions in smoking-attributable hospitalisation rates among all populations in younger age groups (less than 25 years). CONCLUSIONS: Aboriginal Territorians experience much higher smoking-attributable hospitalisation rates than non-Aboriginal Territorians. The scale of the smoking burden and suggestion of recent moderation among Aboriginal men reinforce the importance of tobacco control interventions that are designed to meet the needs of the NT's diverse population groups. Preventing smoking and increasing smoking cessation rates remain priorities for public health interventions in the NT.

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

BACKGROUND: The 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. METHODS: We 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. RESULTS: This 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. CONCLUSIONS: Socio-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.

Long-term trends in Indigenous deaths from chronic diseases in the Northern Territory: a foot on the brake, a foot on the accelerator.

OBJECTIVE: To examine trends in Northern Territory Indigenous mortality from chronic diseases other than cancer. DESIGN: A comparison of trends in rates of mortality from six chronic diseases (ischaemic heart disease [IHD], chronic obstructive pulmonary disease [COPD], cerebrovascular disease [CVD], diabetes mellitus [DM], renal failure [RF] and rheumatic heart disease [RHD]) in the NT Indigenous population with those of the total Australian population. PARTICIPANTS: NT Indigenous and total Australian populations, 1977-2001. MAIN OUTCOME MEASURES: Estimated average annual change in chronic disease mortality rates and in mortality rate ratios. RESULTS: Death rates from IHD and DM among NT Indigenous peoples increased between 1977 and 2001, but this increase slowed after 1990. Death rates from COPD rose before 1990, but fell thereafter. There were non-significant declines in death rates from CVD and RHD. Mortality rates from RF rose in those aged > or = 50 years. The ratios of mortality rates for NT Indigenous to total Australian populations from these chronic diseases increased throughout the period. CONCLUSIONS: Mortality rates from IHD and DM in the NT Indigenous population have been increasing since 1977, but there is evidence of a slower rise (or even a fall) in death rates in the 1990s. These early small changes give reason to hope that some improvements (possibly in medical care) have been putting the brakes on chronic disease mortality among Aboriginal and Torres Strait Islander peoples.