In-hospital outcomes by insurance type among patients undergoing percutaneous coronary interventions for acute myocardial infarction in New South Wales public hospitals.

BACKGROUND: International evidence suggests patients receiving cardiac interventions experience differential outcomes by their insurance status. We investigated outcomes of in-hospital care according to insurance status among patients admitted in public hospitals with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI). METHODS: We conducted a cohort study within the Australian universal health care system with supplemental private insurance. Using linked hospital and mortality data, we included patients aged 18 + years admitted to New South Wales public hospitals with AMI and undergoing their first PCI from 2017-2020. We measured hospital-acquired complications (HACs), length of stay (LOS) and in-hospital mortality among propensity score-matched private and publicly funded patients. Matching was based on socio-demographic, clinical, admission and hospital-related factors. RESULTS: Of 18,237 inpatients, 30.0% were privately funded. In the propensity-matched cohort (n = 10,630), private patients had lower rates of in-hospital mortality than public patients (odds ratio: 0.59, 95% CI: 0.45-0.77; approximately 11 deaths avoided per 1,000 people undergoing PCI procedures). Mortality differences were mostly driven by STEMI patients and those from major cities. There were no significant differences in rates of HACs or average LOS in private, compared to public, patients. CONCLUSION: Our findings suggest patients undergoing PCI in Australian public hospitals with private health insurance experience lower in-hospital mortality compared with their publicly insured counterparts, but in-hospital complications are not related to patient health insurance status. Our findings are likely due to unmeasured confounding of broader patient selection, socioeconomic differences and pathways of care (e.g. access to emergency and ambulatory care; delays in treatment) that should be investigated to improve equity in health outcomes.

Population-wide contribution of medically assisted reproductive technologies to overall births in Australia: temporal trends and parental characteristics.

STUDY QUESTION: In a country with supportive funding for medically assisted reproduction (MAR) technologies, what is the proportion of MAR births over-time? SUMMARY ANSWER: In 2017, 6.7% of births were conceived by MAR (4.8% ART and 1.9% ovulation induction (OI)/IUI) with a 55% increase in ART births and a stable contribution from OI/IUI births over the past decade. WHAT IS KNOWN ALREADY: There is considerable global variation in utilization rates of ART despite a similar infertility prevalence worldwide. While the overall contribution of ART to national births is known in many countries because of ART registries, very little is known about the contribution of OI/IUI treatment or the socio-demographic characteristics of the parents. Australia provides supportive public funding for all forms of MAR with no restrictions based on male or female age, and thus provides a unique setting to investigate the contribution of MAR to national births as well as the socio-demographic characteristics of parents across the different types of MAR births. STUDY DESIGN, SIZE, DURATION: This is a novel population-based birth cohort study of 898 084 births using linked ART registry data and administrative data including birth registrations, medical services, pharmaceuticals, hospital admissions and deaths. Birth (a live or still birth of at least one baby of ≥400 g birthweight or ≥20 weeks' gestation) was the unit of analysis in this study. Multiple births were considered as one birth in our analysis. PARTICIPANTS/MATERIALS, SETTING, METHODS: This study included a total of 898 084 births (606 488 mothers) in New South Wales and the Australian Capital Territory, Australia 2009-2017. We calculated the prevalence of all categories of MAR-conceived births over the study period. Generalized estimating equations were used to examine the association between parental characteristics (parent's age, parity, socio-economic status, maternal country of birth, remoteness of mother's dwelling, pre-existing medical conditions, smoking, etc.) and ART and OI/IUI births relative to naturally conceived births. MAIN RESULTS AND THE ROLE OF CHANCE: The proportion of MAR births increased from 5.1% of all births in 2009 to 6.7% in 2017, representing a 30% increase over the decade. The proportion of OI/IUI births remained stable at around 2% of all births, representing 32% of all MAR births. Over the study period, ART births conceived by frozen embryo-transfer increased nearly 3-fold. OI/IUI births conceived using clomiphene citrate decreased by 39%, while OI/IUI births conceived using letrozole increased 56-fold. Overall, there was a 55% increase over the study period in the number of ART-conceived births, rising to 56% of births to mothers aged 40 years and older. In 2017, almost one in six births (17.6%) to mothers aged 40 years and over were conceived using ART treatment. Conversely, the proportion of OI/IUI births was similar across different mother's age groups and remained stable over the study period. ART children, but not OI/IUI children, were more likely to have parents who were socio-economically advantaged compared to naturally conceived children. For example, compared to naturally conceived births, ART births were 16% less likely to be born to mothers who live in the disadvantaged neighbourhoods after accounting for other covariates (adjusted relative risk (aRR): 0.84 [95% CI: 0.81-0.88]). ART- or OI/IUI-conceived children were 25% less likely to be born to immigrant mothers than births after natural conception (aRR: 0.75 [0.74-0.77]). LIMITATIONS, REASONS FOR CAUTION: The social inequalities that we observed between the parents of children born using ART and naturally conceived children may not directly reflect disparities in accessing fertility care for individuals seeking treatment. WIDER IMPLICATIONS OF THE FINDINGS: With the ubiquitous decline in fertility rates around the world and the increasing trend to delay childbearing, this population-based study enhances our understanding of the contribution of different types of MARs to population profiles among births in high-income countries. The parental socio-demographic characteristics of MAR-conceived children differ significantly from naturally conceived children and this highlights the importance of accounting for such differences in studies investigating the health and development of MAR-conceived children. STUDY FUNDING/COMPETING INTEREST(S): This study was funded through Australian National Health and Medical Research Council (NHMRC) grant: APP1127437. G.M.C. is an employee of The University of New South Wales (UNSW) and Director of the National Perinatal Epidemiology and Statistics Unit (NPESU), UNSW. The NPESU manages the Australian and New Zealand Assisted Reproduction Database with funding support from the Fertility Society of Australia and New Zealand. C.V. is an employee of The University of New South Wales (UNSW), Director of Clinical Research of IVFAustralia, Member of the Board of the Fertility Society of Australia and New Zealand, and Member of Research Committee of School of Women's and Children's Health, UNSW. C.V. reports grants from Australian National Health and Medical Research Council (NHMRC), and Merck KGaA. C.V. reports consulting fees, and payment or honoraria for lectures, presentations, speakers, bureaus, manuscript, writing or educational events or attending meeting or travel from Merck, Merck Sparpe & Dohme, Ferring, Gedon-Richter and Besins outside this submitted work. C.V. reported stock or stock options from Virtus Health Limited outside this submitted work. R.J.N. is an employee of The University of Adelaide, and Chair DSMC for natural therapies trial of The University of Hong Kong. R.J.N. reports grants from NHMRC. R.J.N. reports lecture fees and support for attending or travelling for lecture from Merck Serono which is outside this submitted work. L.R.J. is an employee of The UNSW and Foundation Director of the Centre for Big Data Research in Health at UNSW Sydney. L.R.J. reports grants from NHMRC. The other co-authors have no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Rates of Low-Value Service in Australian Public Hospitals and the Association With Patient Insurance Status.

Importance: Low-value services have limited or no benefit to patients. Rates of low-value service in public hospitals may vary by patient insurance status, given that there may be different financial incentives for treatment of privately insured patients. Objective: To assess the variation in rates of 5 low-value services performed in Australian public hospitals according to patient funding status (ie, private or public). Design, Setting, and Participants: This retrospective cross-sectional study analyzed New South Wales public hospital data from January 2013 to June 2018. Patients included in the sample were over age 18 years and eligible to receive low-value services based on diagnoses and concomitant procedures. Data analysis was conducted from June to December 2020. Main Outcomes and Measures: Hospital-specific rates of low-value knee arthroscopic debridement, vertebroplasty for osteoporotic spinal fractures, hyperbaric oxygen therapy, oophorectomy with hysterectomy, and laparoscopic uterine nerve ablation for chronic pelvic pain were measured. For each measure, rates within each public hospital were compared by patient funding status descriptively and using multilevel models. Results: A total of 219 862 inpatients were included in analysis from 58 public hospitals across the 5 measures. A total of 38 365 (22 904 [59.7%] women; 12 448 [32.4%] aged 71-80 years) were eligible for knee arthroscopic debridement for osteoarthritis; 2520 (1924 [76.3%] women; 662 [26.3%] aged 71-80 years), vertebroplasty for osteoporotic spinal fractures; 162 285 (82 046 [50.6%] women; 28 255 [17.4%] aged 61-70 years), hyperbaric oxygen therapy; 15 916 (7126 [44.8%] aged 41-50 years), oophorectomy with hysterectomy; and 776 (327 [42.1%] aged 18-30 years), uterine nerve ablation for chronic pelvic pain. Overall rates of low-value services varied considerably between measures, with the lowest rate for hyperbaric oxygen therapy (0.3 procedures per 1000 inpatients [47 of 158 220 eligible inpatients]) and the highest for vertebroplasty (30.8 procedures per 1000 eligible patients [77 of 2501 eligible inpatients]). There was significant variation in rates between hospitals, with a few outlying hospitals (ie, <10), particularly for knee arthroscopy (range from 1.8 to 21.0 per 1000 eligible patients) and vertebroplasty (range from 13.1 to 70.4 per 1000 eligible patients), with higher numerical rates of low-value services among patients with private insurance than for those without. However, there was no association overall between patient insurance status and low-value services. Overall differences in rates among those with and without private insurance by individual procedure type were not statistically significant. Conclusions and Relevance: There was significant variation in rates of low-value services in public hospitals. While there was no overall association between private insurance and rate of low-value services, private insurance may be associated with low-value service rates in some hospitals. Further exploration of factors specific to local hospitals and practices are needed to reduce this unnecessary care.

How Much Is a Human Life Worth? A Systematic Review.

OBJECTIVES: To systematically review studies eliciting monetary value of a statistical life (VSL) estimates within, and across, different sectors and other contexts; compare the reported estimates; and critically review the elicitation methods used. METHODS: In June 2019, we searched the following databases to identify methodological and empirical studies: Cochrane Library, Compendex, Embase, Environment Complete, Informit, ProQuest, PubMed, Scopus, and Web of Science. We used the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines for reporting and a modified Consolidated Health Economic Evaluation Reporting Standards checklist to assess the quality of included studies. RESULTS: We identified 1455 studies, of which we included 120 in the systematic review. A stated-preference approach was used in 76 articles, with 51%, 41%, and 8% being contingent valuation studies, discrete-choice experiments, or both, respectively. A revealed-preference approach was used in 43 articles, of which 74% were based on compensating-wage differentials. The human capital approach was used in only 1 article. We assessed most publications (87%) as being of high quality. Estimates for VSL varied substantially by context (sector, developed/developing country, socio-economic status, etc), with the median of midpoint purchasing power parity-adjusted estimates of 2019 US$5.7 million ($6.8 million, $8.7 million, and $5.3 million for health, labor market, and transportation safety sectors, respectively). CONCLUSIONS: The large variation observed in published VSLs depends mainly on the context rather than the method used. We found higher median values for labor markets and developed countries. It is important that health economists and policymakers use context-specific VSL estimates. Methodological innovation and standardization are needed to maximize comparability of VSL estimates within, and across, sectors and methods.

Medications used disproportionately during pregnancy: Priorities for research on the risks and benefits of medications when used during pregnancy.

PURPOSE: To identify medications used disproportionately more or less among pregnant women relative to women of childbearing age. METHODS: Medication use among pregnant women in New South Wales, Australia was identified using linked perinatal and pharmaceutical dispensing data from 2006 to 2012. Medication use in women of childbearing age (including pregnant women) was identified using pharmaceutical dispensing data for a 10% random sample of the Australian population. Pregnant social security beneficiaries (n = 111 612) were age-matched (1:3) to female social security beneficiaries in the 10% sample. For each medication, the risk it was dispensed during pregnancy relative to being dispensed during an equivalent time period among matched controls was computed. Medications were mapped to Australian pregnancy risk categories. RESULTS: Of the 181 included medications, 35 were statistically significantly more commonly dispensed to pregnant women than control women. Of these, 23 are categorised as posing no increased risk to the foetus. Among medications suspected of causing harm or having insufficient safety data, the strongest associations were observed for hydralazine, ondansetron, dalteparin sodium and ranitidine. Use was less likely during pregnancy than control periods for 127 medications, with the strongest associations observed for hormonal contraceptives and progestogens. CONCLUSIONS: Most medications found to be used disproportionately more by pregnant women are indicated for pregnancy-related problems. A large number of medications were used disproportionately less among pregnant women, where avoidance of some of these medications may pose a greater risk of harm. For many other medications avoided during pregnancy, current data are insufficient to inform this risk-benefit assessment.

Identifying patients using antidepressants for the treatment of depression: A predictive algorithm for use in pharmaceutical and medical claims data.

PURPOSE: Records of antidepressant dispensings are often used as a surrogate measure of depression. However, as antidepressants are frequently prescribed for indications other than depression, this is likely to result in misclassification. This study aimed to develop a predictive algorithm that identifies patients using antidepressants for the treatment of depression. METHODS: Pharmaceutical Benefits Scheme (PBS) and Medicare Benefits Schedule (MBS) claims data were linked to follow-up questionnaires (completed in 2012-2013) for participants of the 45 and Up Study-a cohort study of residents of New South Wales, Australia, aged 45 years and older. The sample composed participants who were dispensed an antidepressant in the 30 days prior to questionnaire completion (n = 3162). An algorithm based on patient characteristics, pharmaceutical dispensings, and claims for mental health services was built using group-lasso interaction network (glinternet), with self-reported receipt of treatment for depression as the outcome. The predictive performance of the algorithm was assessed via bootstrap resampling. RESULTS: The algorithm composes 15 main effects and 11 interactions, with type of antidepressant dispensed and claims for mental health services the strongest predictors. The ability of the algorithm to discriminate between antidepressant users with and without depression was 0.73. At a predicted probability cut-off of 0.6, specificity was 93.8% and sensitivity was 23.6%. CONCLUSIONS: Using this algorithm with a high probability cut-off yields high specificity and facilitates the exclusion of individuals using antidepressants for indications other than depression, thereby mitigating the risk of confounding by indication when evaluating the outcomes of antidepressant use.

Compliance with telephone triage advice among adults aged 45 years and older: an Australian data linkage study.

BACKGROUND: Middle-aged and older patients are prominent users of telephone triage services for timely access to health information and appropriate referrals. Non-compliance with advice to seek appropriate care could potentially lead to poorer health outcomes among those patients. It is imperative to assess the extent to which middle-aged and older patients follow triage advice and how this varies according to their socio-demographic, lifestyle and health characteristics as well as features of the call. METHODS: Records of calls to the Australian healthdirect helpline (July 2008-December 2011) were linked to baseline questionnaire data from the 45 and Up Study (participants age ≥ 45 years), records of emergency department (ED) presentations, hospital admissions, and medical consultation claims. Outcomes of the call included compliance with the advice "Attend ED immediately"; "See a doctor (immediately, within 4 hours, or within 24 hours)"; "Self-care"; and self-referral to ED or hospital within 24 h when given a self-care or low-urgency care advice. Multivariable logistic regression was used to investigate associations between call outcomes and patient and call characteristics. RESULTS: This study included 8406 adults (age ≥ 45 years) who were subjects of 11,088 calls to the healthdirect helpline. Rates of compliance with the advices "Attend ED immediately", "See a doctor" and "Self-care" were 68.6%, 64.6% and 77.5% respectively, while self-referral to ED within 24 h followed 7.0% of calls. Compliance with the advice "Attend ED immediately" was higher among patients who had three or more positive lifestyle behaviours, called after-hours, or stated that their original intention was to attend ED, while it was lower among those who lived in rural and remote areas or reported high or very high levels of psychological distress. Compliance with the advice "See a doctor" was higher in patients who were aged ≥65 years, worked full-time, or lived in socio-economically advantaged areas, when another person made the call on the patient's behalf, and when the original intention was to seek care from an ED or a doctor. It was lower among patients in rural and remote areas and those taking five medications or more. Patients aged ≥65 years were less likely to comply with the advice "Self-care". The rates of self-referral to ED within 24 h were greater in patients from disadvantaged areas, among calls made after-hours or by another person, and when the original intention was to attend ED. Patients who were given a self-care or low-urgency care advice, whose calls concerned bleeding, cardiac, gastrointestinal, head and facial injury symptoms, were more likely to self-refer to ED. CONCLUSIONS: Compliance with telephone triage advice among middle-age and older patients varied substantially according to both patient- and call-related factors. Knowledge about the patients who are less likely to comply with telephone triage advice, and about characteristics of calls that may influence compliance, will assist in refining patient triage protocols and referral pathways, training staff and tailoring service design and delivery to achieve optimal patient compliance.

Access to Subsidized Smoking Cessation Medications by Australian Smokers Aged 45 Years and Older: A Population-Based Cohort Study.

INTRODUCTION: The principal aim of this study was to assess the accessibility of subsidized cessation medications to socioeconomically disadvantaged smokers, including smokers living in regional and remote communities. METHODS: Analyses used baseline questionnaire and linked Pharmaceutical Benefits Scheme data for 18 686 regular smokers participating in the 45 and Up Study, a large-scale Australian cohort study of people aged 45 years and older. Participants who were dispensed nicotine replacement therapy, varenicline, or bupropion were identified from the Pharmaceutical Benefits Scheme data, which provide an essentially complete record of participants' access to subsidized pharmaceuticals. Associations between the supply of each pharmacotherapy and a range of sociodemographic and health-related variables were evaluated using multiple logistic regression. RESULTS: The odds that participants were supplied with a cessation medication declined markedly with increasing age for participants older than 60 years and were substantially higher for participants who smoked 20 or more cigarettes/day than for participants who smoked fewer than 10 cigarettes/day. Participants with no formal qualification and those residing in socioeconomically disadvantaged areas had higher odds of receiving nicotine replacement therapy or varenicline than university-educated participants and participants living in the least disadvantaged areas. There was no evidence that participants residing in regional and remote communities had lower odds of receiving a cessation medication than participants residing in major cities. CONCLUSIONS: Older Australian smokers' access to cessation pharmacotherapies is determined predominantly by age and daily cigarette consumption and does not appear to be limited by educational achievement, socioeconomic disadvantage, or remoteness. IMPLICATIONS: Promoting the use of cessation medications is a principal measure proposed to achieve Australia's National Tobacco Strategy 2012-2018 goal of reducing cigarette consumption among socioeconomically disadvantaged smokers. The results of this large-scale cohort study indicate that access to cessation pharmacotherapies is determined primarily by age and daily cigarette consumption, and is not limited by socioeconomic circumstances, providing some reassurance that existing government subsidies are sufficient to ensure that pharmaceutical aids are accessible to all Australian smokers.

Variation in the use of primary care services for diabetes management according to country of birth and geography among older Australians.

AIMS: To investigate variation according to country of birth and geography in the use of primary care services funded through Medicare Australia-Australian universal health insurance-for diabetes annual cycle of care among older overseas-born Australians with type-2 diabetes. METHODS: Records of Medicare claims for medical services were linked to self-administered questionnaire data for people with type-2 diabetes enrolled in the 45 and Up Study, including 840 participants born in Italy, Greece, Vietnam, Lebanon, China, India, or the Philippines and 12,444 participants born in Australia, living in 195 statistical local areas (SLAs) in New South Wales, Australia. Study outcomes included ≥6 claims for general practitioner (GP) visits, at least one claim for specialist, optometrist, Practice Incentive Payment for completion of diabetes annual cycle of care (PIP), GP Management Plan or Team Care Arrangement (GPMP/TCA), allied health, blood tests for glycosylated haemoglobin (HbA1c) and cholesterol, and urine test for micro-albumin. Multivariable multilevel logistic regression was performed, controlling for personal socio-demographic and health characteristics and geographical area remoteness and socio-economic status. RESULTS: Compared with Australia-born participants, people born in Vietnam and China had significantly lower rates of claims for allied health services (odds ratio [OR] 0.14, 95% confidence interval [CI] 0.05-0.43, and OR 0.40, 95%CI 0.18-0.87, respectively), those born in Italy had lower rates of PIP claims (OR 0.60, 95%CI 0.39-0.92) and micro-albuminuria testings (OR 0.65, 95%CI 0.47-0.89), and those born in the Philippines had lower claims for specialist services (OR 0.59, 95%CI 0.38-0.91). Participants born in Greece and China (GP visits), Vietnam (optometrist services), and India (micro-albuminuria tests) were more likely to claims for these services than Australia-born people. Significant geographic variation was observed for all study outcomes, with the greatest variations in claims for allied health services (variation 9.3%, median odds ratio [MOR] 1.74, 95% credible interval [CrI] 1.60-2.01), PIP (7.8%, MOR 1.65, 95%CrI 1.55-1.83), and GPMP/TCA items (6.6%, MOR 1.58, 95%CrI 1.49-1.73). CONCLUSIONS: Different approach among geographical areas and intervention programs for identified cultural groups and their providers are warranted to improve disparities in diabetes care.

The relationship between body mass index and hospitalisation rates, days in hospital and costs: findings from a large prospective linked data study.

BACKGROUND: Internationally there is limited empirical evidence on the impact of overweight and obesity on health service use and costs. We estimate the burden of hospitalisation-admissions, days and costs-associated with above-normal BMI. METHODS: Population-based prospective cohort study involving 224,254 adults aged ≥45y in Australia (45 and Up Study). Baseline questionnaire data (2006-2009) were linked to hospitalisation and death records (median follow-up 3.42y) and hospital cost data. The relationships between BMI and hospital admissions and days were modelled using zero-inflated negative binomial regression; generalised gamma models were used to model costs. Analyses were stratified by sex and age (45-64, 65-79, ≥80y), and adjusted for age, area of residence, education, income, smoking, alcohol-intake and private health insurance status. Population attributable fractions were also calculated. RESULTS: There were 459,346 admissions (0.55/person-year) and 1,483,523 hospital days (1.76/person-year) during follow-up. For ages 45-64y and 65-79y, rates of admissions, days and costs increased progressively with increments of above-normal BMI. Compared to BMI 22.5-<25kg/m2, rates of admissions and days were 1.64-2.54 times higher for BMI 40-50kg/m2; costs were 1.14-1.24 times higher for BMI 27.5-<30kg/m2, rising to 1.77-2.15 times for BMI 40-50kg/m2. The BMI-hospitalisation relationship was less clear for ≥80y. We estimated that among Australians 45-79y, around 1 in every 8 admissions are attributable to overweight and obesity (2% to overweight, 11% to obesity), as are 1 in every 6 days in hospital (2%, 16%) and 1 in every 6 dollars spent on hospitalisation (3%, 14%). CONCLUSIONS: The dose-response relationship between BMI and hospital use and costs in mid-age and older Australians in the above-normal BMI range suggests even small downward shifts in BMI among these people could result in considerable reductions in their annual health care costs; whether this would result in long-term savings to the health care system is not known from this study.

Sociodemographic and health characteristics, rather than primary care supply, are major drivers of geographic variation in preventable hospitalizations in Australia.

BACKGROUND: Geographic rates of preventable hospitalization are used internationally as an indicator of accessibility and quality of primary care. Much research has correlated the indicator with the supply of primary care services, yet multiple other factors may influence these admissions. OBJECTIVE: To quantify the relative contributions of the supply of general practitioners (GPs) and personal sociodemographic and health characteristics, to geographic variation in preventable hospitalization. METHODS: Self-reported questionnaire data for 267,091 participants in the 45 and Up Study, Australia, were linked with administrative hospital data to identify preventable hospitalizations. Multilevel Poisson models, with participants clustered in their geographic area of residence, were used to explore factors that explain geographic variation in hospitalization. RESULTS: GP supply, measured as full-time workload equivalents, was not a significant predictor of preventable hospitalization, and explained only a small amount (2.9%) of the geographic variation in hospitalization rates. Conversely, more than one-third (36.9%) of variation was driven by the sociodemographic composition, health, and behaviors of the population. These personal characteristics explained a greater amount of the variation for chronic conditions (37.5%) than acute (15.5%) or vaccine-preventable conditions (2.4%). CONCLUSIONS: Personal sociodemographic and health characteristics, rather than GP supply, are major drivers of preventable hospitalization. Their contribution varies according to condition, and if used for performance comparison purposes, geographic rates of preventable hospitalization should be reported according to individual condition or potential pathways for intervention.

Linking birth records to hospital admission records enhances the identification of women who smoke during pregnancy.

OBJECTIVE: Birth records and hospital admission records are valuable for research on maternal smoking, but individually are known to under-estimate smokers. This study investigated the extent to which combining data from these records enhances the identification of pregnant smokers, and whether this affects research findings such as estimates of maternal smoking prevalence and risk of adverse pregnancy outcomes associated with smoking. METHODS: A total of 846,039 birth records in New South Wales, Australia, (2001-2010) were linked to hospital admission records (delivery and antenatal). Algorithm 1 combined data from birth and delivery admission records, whereas algorithm 2 combined data from birth record, delivery and antenatal admission records. Associations between smoking and placental abruption, preterm birth, stillbirth, and low birthweight were assessed using multivariable logistic regression. RESULTS: Algorithm 1 identified 127,612 smokers (smoking prevalence 15.1%), which was a 9.6% and 54.6% increase over the unenhanced identification from birth records alone (prevalence 13.8%), and delivery admission records alone (prevalence 9.8%), respectively. Algorithm 2 identified a further 2,408 smokers from antenatal admission records. The enhancement varied by maternal socio-demographic characteristics (age, marital status, country of birth, socioeconomic status); obstetric factors (multi-fetal pregnancy, diabetes, hypertension); and maternity hospital. Enhanced and unenhanced identification methods yielded similar odds ratios for placental abruption, preterm birth, stillbirth and low birthweight. CONCLUSIONS: Use of linked data improved the identification of pregnant smokers. Studies relying on a single data source should adjust for the under-ascertainment of smokers among certain obstetric populations.

The contribution of geography to disparities in preventable hospitalisations between indigenous and non-indigenous Australians.

OBJECTIVES: To quantify the independent roles of geography and Indigenous status in explaining disparities in Potentially Preventable Hospital (PPH) admissions between Indigenous and non-Indigenous Australians. DESIGN, SETTING AND PARTICIPANTS: Analysis of linked hospital admission data for New South Wales (NSW), Australia, for the period July 1 2003 to June 30 2008. MAIN OUTCOME MEASURES: Age-standardised admission rates, and rate ratios adjusted for age, sex and Statistical Local Area (SLA) of residence using multilevel models. RESULTS: PPH diagnoses accounted for 987,604 admissions in NSW over the study period, of which 3.7% were for Indigenous people. The age-standardised PPH admission rate was 76.5 and 27.3 per 1,000 for Indigenous and non-Indigenous people respectively. PPH admission rates in Indigenous people were 2.16 times higher than in non-Indigenous people of the same age group and sex who lived in the same SLA. The largest disparities in PPH admission rates were seen for diabetes complications, chronic obstructive pulmonary disease and rheumatic heart disease. Both rates of PPH admission in Indigenous people, and the disparity in rates between Indigenous than non-Indigenous people, varied significantly by SLA, with greater disparities seen in regional and remote areas than in major cities. CONCLUSIONS: Higher rates of PPH admission among Indigenous people are not simply a function of their greater likelihood of living in rural and remote areas. The very considerable geographic variation in the disparity in rates of PPH admission between Indigenous and non-Indigenous people indicates that there is potential to reduce unwarranted variation by characterising outlying areas which contribute the most to this disparity.

Disparities in cataract surgery between Aboriginal and non-Aboriginal people in New South Wales, Australia.

BACKGROUND: To investigate variation in rates of cataract surgery in New South Wales, Australia by area of residence for Aboriginal and non-Aboriginal adults. DESIGN: Observational data linkage study of hospital admissions. PARTICIPANTS: Two hundred eighty-nine thousand six hundred forty-six New South Wales residents aged 30 years and over admitted to New South Wales hospitals for 444,551 cataract surgery procedures between 2001 and 2008. METHODS: Analysis of linked routinely collected hospital data using direct standardization and multilevel negative binomial regression models accounting for clustering of individuals within Statistical Local Areas. MAIN OUTCOME MEASURES: Age-standardized cataract surgery rates and adjusted rate ratios. RESULTS: Aboriginal people had lower rates of cataract procedures than non-Aboriginal people of the same age and sex, living in the same Statistical Local Area (adjusted rate ratio 0.71, 95% confidence interval 0.68-0.75). There was significant variation in cataract surgery rates across Statistical Local Areas for both Aboriginal and non-Aboriginal people, with the disparity greater in major cities and less disadvantaged areas. Rates of surgery were lower for Aboriginal than non-Aboriginal people in most Statistical Local Areas, but in a few, the rates were similar or higher for Aboriginal people. CONCLUSIONS: Aboriginal people in New South Wales received less cataract surgery than non-Aboriginal people, despite evidence of higher cataract rates. This disparity was greatest in urban and wealthier areas. Higher rates of surgery for Aboriginal people observed in some specific locations are likely to reflect the availability of public ophthalmology services, targeted services for Aboriginal people and higher demand for surgery in these populations.

Statistical methods to enhance reporting of Aboriginal Australians in routine hospital records using data linkage affect estimates of health disparities.

OBJECTIVE: To investigate under-recording of Aboriginal people in hospital data from New South Wales (NSW), Australia, define algorithms for enhanced reporting, and examine the impact of these algorithms on estimated disparities in cardiovascular and injury outcomes. METHODS: NSW Admitted Patient Data were linked with NSW mortality data (2001-2007). Associations with recording of Aboriginal status were investigated using multilevel logistic regression. The number of admissions reported as Aboriginal according to six algorithms was compared with the original (unenhanced) Aboriginal status variable. Age-standardised admission, and 30- and 365-day mortality ratios were estimated for cardiovascular disease and injury. RESULTS: Sixty per cent of the variation in recording of Aboriginal status was due to the hospital of admission, with poorer recording in private and major city hospitals. All enhancement algorithms increased the number of admissions reported as Aboriginal, from between 4.1% and 37.8%. Admission and mortality ratios varied markedly between algorithms, with less strict algorithms resulting in higher admission rate ratios, but generally lower mortality rate ratios, particularly for cardiovascular disease. CONCLUSIONS: The choice of enhancement algorithm has an impact on the number of people reported as Aboriginal and on estimated outcome ratios. The influence of the hospital on recording of Aboriginal status highlights the importance of continued efforts to improve data collection. IMPLICATIONS: Estimates of Aboriginal health disparity can change depending on how Aboriginal status is reported. Sensitivity analyses using a number of algorithms are recommended.

Quantifying under-reporting of pathology tests in Medical Benefits Schedule claims data.

OBJECTIVE: We investigated the completeness of recording of pathology tests in Australian Medical Benefits Schedule (MBS) claims data, using the example of the prostate-specific antigen (PSA) test. With some exceptions, MBS claims data records only the three most expensive pathology items in an episode of care, and this practice ('episode coning') means that pathology tests can be under-recorded. METHODS: The analysis used MBS data for male participants in the 45 and Up Study. The number and cost of items in each episode of care were used to determine whether an episode contained a PSA screening test (Item 66655), or could have lacked a record of this item because of episode coning. RESULTS: MBS data for 1070392 episodes involving a request for a pathology test for 118074 men were analysed. Of these episodes, 11% contained a request for a PSA test; a further 7.5% may have been missing a PSA request that was not recorded because of episode coning. CONCLUSIONS: It is important to consider under-reporting of pathology tests as a result of episode coning when interpreting MBS claims data. Episode coning creates uncertainty about whether a person has received any given pathology test. The extent of this uncertainty can be estimated by determining the proportion of episodes in which the test may have been performed but was not recorded due to episode coning.

The Smoking MUMS (Maternal Use of Medications and Safety) Study: protocol for a population-based cohort study using linked administrative data.

INTRODUCTION: Approximately 14% of Australian women smoke during pregnancy. Although the risk of adverse outcomes is reduced by smoking cessation, less than 35% of Australian women quit smoking spontaneously during pregnancy. Evidence for the efficacy of bupropion, varenicline or nicotine replacement therapy as smoking cessation aids in the non-pregnant population suggest that pharmacotherapy for smoking cessation is worth exploring in women of childbearing age. Currently, little is known about the utilisation, effectiveness and safety of pharmacotherapies for smoking cessation during pregnancy; neither the extent to which they are used prior to pregnancy nor whether their use has changed in response to related policy reforms. The Smoking MUMS (Maternal Use of Medications and Safety) Study will explore these issues using linked person-level data for a population-based cohort of Australian mothers. METHODS AND ANALYSIS: The cohort will be assembled by linking administrative health records for all women who gave birth in New South Wales or Western Australia since 2003 and their children, including records relating to childbirth, use of pharmaceuticals, hospital admissions, emergency department presentations and deaths. These longitudinal linked data will be used to identify utilisation of smoking cessation pharmacotherapies during and between pregnancies and to explore the associated smoking cessation rates and maternal and child health outcomes. Subgroup and temporal analyses will identify potential differences between population groups including indigenous mothers and social security recipients and track changes associated with policy reforms that have made alternative smoking cessation pharmacotherapies available. ETHICS AND DISSEMINATION: Ethical approval has been obtained for this study. To enhance the translation of the project's findings into policy and practice, policy and clinical stakeholders will be engaged through a reference group and a policy forum will be held. Outputs from the project will include scientific papers and summary reports designed for policy audiences.

Disentangling the impacts of geography and Aboriginality on serious road transport injuries in New South Wales.

Aboriginal people in Australia have higher rates of transport injury than non-Aboriginal people, but a greater proportion of Aboriginal people live in rural or remote areas where risk of these injuries is higher. This paper investigated the contributing effect of geography on the relationship between Aboriginality and road transport injury rates in the state of New South Wales. Linked hospital admission and mortality records for individuals for the years 2001-2007 were grouped into distinct injury events. Multilevel Poisson regression was used to examine disparities in injury rates between Aboriginal and non-Aboriginal people clustered within geographic areas of residence. Overall, Aboriginal people had higher rates of road transport injuries (IRR: 1.18, 95% CIs: 1.09-1.28). However, there was no significant difference when geographic clustering was taken into account (IRR: 1.00, 95% CIs: 0.96-1.04). This effect was further influenced by mode of transport for the injury, with Aboriginal people having higher rates of pedestrian (IRR: 1.96, 95% CIs: 1.75-2.19) and lower rates of motorcycle (IRR: 0.64, 95% CIs: 0.59-0.70) injuries in all almost all local areas, while there was no systematic pattern across geographic areas for small vehicle injuries (IRR: 1.01, 95% CIs: 0.94-1.08). Geography plays an important role in the population disparity of road transport injuries between Aboriginal and non-Aboriginal people, and has a differential impact for different types of road transport injury. Exploring how individual and geographic factors influence patterns of disparity allows for clearer targeting of future intervention strategies.

Disparities in revascularization rates after acute myocardial infarction between aboriginal and non-aboriginal people in Australia.

BACKGROUND: This study examined revascularization rates after acute myocardial infarction (AMI) for Aboriginal and non-Aboriginal patients sequentially controlling for admitting hospital and risk factors. METHODS AND RESULTS: Hospital data from the state of New South Wales, Australia (July 2000 through December 2008) were linked to mortality data (July 2000 through December 2009). The study sample were all people aged 25 to 84 years admitted to public hospitals with a diagnosis of AMI (n=59 282). Single level and multilevel Cox regression was used to estimate rates of revascularization within 30 days of admission. A third (32.9%) of Aboriginal AMI patients had a revascularization within 30 days compared with 39.7% non-Aboriginal patients. Aboriginal patients had a revascularization rate 37% lower than non-Aboriginal patients of the same age, sex, year of admission, and AMI type (adjusted hazard ratio, 0.63; 95% confidence interval, 0.57-0.70). Within the same hospital, however, Aboriginal patients had a revascularization rate 18% lower (adjusted hazard ratio, 0.82; 95% confidence interval, 0.74-0.91). Accounting for comorbidities, substance use and private health insurance further explained the disparity (adjusted hazard ratio, 0.96; 95% confidence interval, 0.87-1.07). Hospitals varied markedly in procedure rates, and this variation was associated with hospital size, remoteness, and catheterization laboratory facilities. CONCLUSIONS: Aboriginal Australians were less likely to have revascularization procedures after AMI than non-Aboriginal Australians, and this was largely explained by lower revascularization rates at the hospital of first admission for all patients admitted to smaller regional and rural hospitals, a higher comorbidity burden for Aboriginal people, and to a lesser extent a lower rate of private health insurance among Aboriginal patients.

Inequalities in bariatric surgery in Australia: findings from 49,364 obese participants in a prospective cohort study.

OBJECTIVES: To investigate variation, and quantify socioeconomic inequalities, in the uptake of primary bariatric surgery in an obese population. DESIGN, SETTING AND PARTICIPANTS: Prospective population-based cohort study of 49,364 individuals aged 45-74 years with body mass index (BMI)≥30 kg/m2. Data from questionnaires (distributed from 1 January 2006 to 31 December 2008) were linked to hospital and death data to 30 June 2010. The sample was drawn from the 45 and Up Study (approximately 10% of New South Wales population aged 45 included, response rate approximately 18%). MAIN OUTCOME MEASURES: Rates of bariatric surgery and adjusted rate ratios (RRs) in relation to health and sociodemographic characteristics. RESULTS: Over 111,757 person-years (py) of follow-up, 312 participants had bariatric surgery, a rate of 27.92 per 10,000 py (95% CI, 24.91-31.19). Rates were highest in women, those living in major cities and those with diabetes, and increased significantly with a higher BMI and number of chronic health conditions. Adjusted RRs were 5.27 (95% CI, 3.18-8.73) for those with annual household income≥ $70 000 versus those with household income<$20,000, and 4.01 (95% CI, 2.41-6.67) for those living in areas in the least disadvantaged quintile versus those in the most disadvantaged quintile. Having versus not having private health insurance (age- and sex-adjusted RR, 9.25; 95% CI, 5.70-15.00) partially explained the observed inequalities. CONCLUSIONS: Bariatric surgery has been shown to be cost-effective in treating severe obesity and associated illnesses. While bariatric surgery rates in Australia are higher in those with health problems, large socioeconomic inequalities are apparent. Our findings suggest these procedures are largely available to those who can afford private health insurance and associated out-of-pocket costs, with poor access in populations who are most in need. Continuing inequalities in access are likely to exacerbate existing inequalities in obesity and related health problems.