Investigating local variation in disease rates within high-rate regions identified using smoothing.

Exploratory disease maps are designed to identify risk factors of disease and guide appropriate responses to disease and helpseeking behaviour. However, when produced using aggregatelevel administrative units, as is standard practice, disease maps may mislead users due to the Modifiable Areal Unit Problem (MAUP). Smoothed maps of fine-resolution data mitigate the MAUP but may still obscure spatial patterns and features. To investigate these issues, we mapped rates of Mental Health- Related Emergency Department (MHED) presentations in Perth, Western Australia, in 2018/19 using Australian Bureau of Statistics (ABS) Statistical Areas Level 2 (SA2) boundaries and a recent spatial smoothing technique: the Overlay Aggregation Method (OAM). Then, we investigated local variation in rates within high-rate regions delineated using both approaches. The SA2- and OAM-based maps identified two and five high-rate regions, respectively, with the latter not conforming to SA2 boundaries. Meanwhile, both sets of high-rate regions were found to comprise a select number of localised areas with exceptionally high rates. These results demonstrate how, due to the MAUP, disease maps that are produced using aggregate-level administrative units are unreliable as a basis for delineating geographic regions of interest for targeted interventions. Instead, reliance on such maps to guide responses may compromise the efficient and equitable delivery of healthcare. Detailed investigation of local variation in rates within high-rate regions identified using both administrative units and smoothing is required to improve hypothesis generation and the design of healthcare responses.

Improving the Efficiency of Geographic Target Regions for Healthcare Interventions.

Appropriate prioritisation of geographic target regions (TRs) for healthcare interventions is critical to ensure the efficient distribution of finite healthcare resources. In delineating TRs, both 'targeting efficiency', i.e., the return on intervention investment, and logistical factors, e.g., the number of TRs, are important. However, existing approaches to delineate TRs disproportionately prioritise targeting efficiency. To address this, we explored the utility of a method found within conservation planning: the software Marxan and an extension, MinPatch ('Marxan + MinPatch'), with comparison to a new method we introduce: the Spatial Targeting Algorithm (STA). Using both simulated and real-world data, we demonstrate superior performance of the STA over Marxan + MinPatch, both with respect to targeting efficiency and with respect to adequate consideration of logistical factors. For example, by design, and unlike Marxan + MinPatch, the STA allows for user-specification of a desired number of TRs. More broadly, we find that, while Marxan + MinPatch does consider logistical factors, it also suffers from several limitations, including, but not limited to, the requirement to apply two separate software tools, which is burdensome. Given these results, we suggest that the STA could reasonably be applied to help prevent inefficiencies arising due to targeting of interventions using currently available approaches.

A modelling analysis of the effectiveness of second wave COVID-19 response strategies in Australia.

There is a significant challenge in responding to second waves of COVID-19 cases, with governments being hesitant in introducing hard lockdown measures given the resulting economic impact. In addition, rising case numbers reflect an increase in coronavirus transmission some time previously, so timing of response measures is highly important. Australia experienced a second wave from June 2020 onwards, confined to greater Melbourne, with initial social distancing measures failing to reduce rapidly increasing case numbers. We conducted a detailed analysis of this outbreak, together with an evaluation of the effectiveness of alternative response strategies, to provide guidance to countries experiencing second waves of SARS-Cov-2 transmission. An individual-based transmission model was used to (1) describe a second-wave COVID-19 epidemic in Australia; (2) evaluate the impact of lockdown strategies used; and (3) evaluate effectiveness of alternative mitigation strategies. The model was calibrated using daily diagnosed case data prior to lockdown. Specific social distancing interventions were modelled by adjusting person-to-person contacts in mixing locations. Modelling earlier activation of lockdown measures are predicted to reduce total case numbers by more than 50%. Epidemic peaks and duration of the second wave were also shown to reduce. Our results suggest that activating lockdown measures when second-wave case numbers first indicated exponential growth, would have been highly effective in reducing COVID-19 cases. The model was shown to realistically predict the epidemic growth rate under the social distancing measures applied, validating the methods applied. The timing of social distancing activation is shown to be critical to their effectiveness. Data showing exponential rise in cases, doubling every 7-10 days, can be used to trigger early lockdown measures. Such measures are shown to be necessary to reduce daily and total case numbers, and the consequential health burden, so preventing health care facilities being overwhelmed. Early control of second wave resurgence potentially permits strict lockdown measures to be eased earlier.

The clinical features that contribute to poor bone health in young Australians living with cystic fibrosis: A recommendation for BMD screening.

BACKGROUND: For Australians living with cystic fibrosis (CF), increased longevity means greater consideration needs to be given to long-term endocrine sequelae such as CF-related bone disease. Deficits in bone mass accrual are most likely to occur during childhood and adolescence. Current guidelines in Australia suggest repeat dual-energy X-ray absorptiometry (DXA) scans every 2 years. This study aims to stratify clinical factors that determine future bone health in the Australian CF population and use this to guide a more streamlined approach to bone health screening. METHODS: This study was a retrospective audit of all patients diagnosed with CF who were treated at the Royal Children's Hospital Melbourne, Australia from 2000 to 2016 (n = 453). Two hundred and two patients had a DXA scan in the study period (191 with height-adjusted data) and 111 patients had more than one scan (108 with height-adjusted data). An investigation into the associations between bone mineral density (BMD) Z score and potential risk factors was conducted using DXA and historical data. RESULTS: The main predictor of future BMD was the previous BMD Z score (p < .001). Other factors found to be determinants of BMD included nutritional status, lung function (FEV1 ), age, history of previous fracture, oral corticosteroid use, and the number of hospital admissions. However, after adjusting for previous BMD, evidence of an association remained only with nutritional status, FEV1 , and number of hospital admissions. CONCLUSION: Second yearly scans may be unnecessary in children with an adequate DXA score on the initial scan who remain clinically stable. However, clinical deterioration in those whose BMD was previously normal, may require closer monitoring of bone health. We propose a guideline for the frequency of DXA monitoring in relation to clinical risk factors.

Modelling the Relationship between Rainfall and Mental Health Using Different Spatial and Temporal Units.

Drought is thought to impact upon the mental health of agricultural communities, but studies of this relationship have reported inconsistent results. A source of inconsistency could be the aggregation of data by a single spatiotemporal unit of analysis, which induces the modifiable areal and temporal unit problems. To investigate this, mental health-related emergency department (MHED) presentations among residents of the Wheat Belt region of Western Australia, between 2002 and 2017, were examined. Average daily rainfall was used as a measure of drought. Associations between MHED presentations and rainfall were estimated based on various spatial aggregations of underlying data, at multiple temporal windows. Wide variation amongst results was observed. Despite this, two key features were found: Associations between MHED presentations and rainfall were generally positive when rainfall was measured in summer months (rate ratios up to 1.05 per 0.5 mm of daily rainfall) and generally negative when rainfall was measured in winter months (rate ratios as low as 0.96 per 0.5 mm of daily rainfall). These results demonstrate that the association between drought and mental health is quantifiable; however, the effect size is small and varies depending on the spatial and temporal arrangement of the underlying data. To improve understanding of this association, more studies should be undertaken with longer time spans and examining specific mental health outcomes, using a wide variety of spatiotemporal units.

Impact of the modifiable areal unit problem in assessing determinants of emergency department demand.

OBJECTIVE: To examine the impact of the modifiable areal unit problem (MAUP) in an investigation of factors associated with ED demand in Perth, Western Australia, in 2016. Furthermore, to advocate a means of avoiding this impact. METHODS: ED presentations were classified as: urgent medical, non-urgent medical, urgent trauma or non-urgent trauma. In each group, sex-stratified, age-adjusted multivariate associations with socio-economic status and distance to the nearest ED and general practitioner (GP) were estimated. Modelling was undertaken using different sets of spatial units: Australian Bureau of Statistics (ABS) Statistical Areas Level 1 (SA1s) and numerous aggregate-level zonations of SA1s (ABS SA2s and others). RESULTS: Estimates obtained using the different units often varied widely: for seven (30%) of 24 strata defined by combinations of sex, ED type and covariate, the smallest and largest effect sizes differed in terms of direction; further, for 11 (65%) of the remaining 17 strata, the largest effect size was at least twice as high as the smallest. This demonstrates the MAUP's impact and that analyses based on a single set of spatial units are unreliable. To resolve the observed variation, we highlight the SA1-level estimates. CONCLUSIONS: When formulating interventions targeting reduced ED utilisation, policy planners should be guided by evidence based on analysis of appropriate spatial units. This ideal is undermined by the widespread lack of acknowledgement of the MAUP in studies examining drivers of ED demand using spatially aggregated data. To avoid the MAUP, only estimates obtained through examining a minimal geographic unit should be relied upon.

Overcoming inefficiencies arising due to the impact of the modifiable areal unit problem on single-aggregation disease maps.

BACKGROUND: In disease mapping, fine-resolution spatial health data are routinely aggregated for various reasons, for example to protect privacy. Usually, such aggregation occurs only once, resulting in 'single-aggregation disease maps' whose representation of the underlying data depends on the chosen set of aggregation units. This dependence is described by the modifiable areal unit problem (MAUP). Despite an extensive literature, in practice, the MAUP is rarely acknowledged, including in disease mapping. Further, despite single-aggregation disease maps being widely relied upon to guide distribution of healthcare resources, potential inefficiencies arising due to the impact of the MAUP on such maps have not previously been investigated. RESULTS: We introduce the overlay aggregation method (OAM) for disease mapping. This method avoids dependence on any single set of aggregate-level mapping units through incorporating information from many different sets. We characterise OAM as a novel smoothing technique and show how its use results in potentially dramatic improvements in resource allocation efficiency over single-aggregation maps. We demonstrate these findings in a simulation context and through applying OAM to a real-world dataset: ischaemic stroke hospital admissions in Perth, Western Australia, in 2016. CONCLUSIONS: The ongoing, widespread lack of acknowledgement of the MAUP in disease mapping suggests that unawareness of its impact is extensive or that impact is underestimated. Routine implementation of OAM can help avoid resource allocation inefficiencies associated with this phenomenon. Our findings have immediate worldwide implications wherever single-aggregation disease maps are used to guide health policy planning and service delivery.

Anxiety and alcohol in the working-age population are driving a rise in mental health-related emergency department presentations: 15 year trends in emergency department presentations in Western Australia.

OBJECTIVE: To evaluate age, gender and disease-specific trends in ED for mental health presentations over 15 years. METHODS: The study population consisted of residents of metropolitan Perth, Western Australia, presenting to Perth ED between 1 July 2002 and 30 June 2017. Population rates of mental health-related ED presentations per year were calculated. RESULTS: Rates of mental health ED presentations are significantly increasing in the working-age population for those with stress and anxiety-related diagnoses, particularly in younger females, and also for alcohol-related presentations for those aged 10-49 years, particularly in males. CONCLUSION: The present study demonstrates that increased rates of mental health-related ED presentations are driven by increased rates of presentation for stress and anxiety-related and alcohol-related presentations in both genders across the working-age population.

Hospital admissions and emergency department presentations for dental conditions indicate access to hospital, rather than poor access to dental health care in the community.

High rates of dental-related potentially preventable hospitalisations are thought to reflect poor access to non-hospital dental services. The association between accessibility (geographic and financial) to non-hospital dentists and potentially preventable hospitalisations was examined in Western Australia. Areas with persistently high rates of dental-related potentially preventable hospitalisations and emergency department (ED) presentations were mapped. Statistical models examined factors associated with these events. Persistently high rates of dental-related potentially preventable hospitalisations were clustered in metropolitan areas that were socioeconomically advantaged and had more dentists per capita (RR 1.06, 95% CI 1.04-1.08) after adjusting for age, sex, socioeconomics, and Aboriginality. Persistently high rates of ED presentations were clustered in socioeconomically disadvantaged areas near metropolitan EDs and with fewer dentists per capita (RR 0.91, 0.88-0.94). A positive association between dental-related potentially preventable hospitalisations and poor (financial or geographic) access to dentists was not found. Rather, rates of such events were positively associated with socioeconomic advantage, plus greater access to hospitals and non-hospital dental services. Furthermore, ED presentations for dental conditions are inappropriate indicators of poor access to non-hospital dental services because of their relationship with hospital proximity. Health service planners and policymakers should pursue alternative indicators of dental service accessibility.

Bone mineral density is related to lung function outcomes in young people with cystic fibrosis-A retrospective study.

INTRODUCTION: Improvements in the medical management of cystic fibrosis (CF) in recent years have resulted in increased prevalence of long-term sequelae of the condition, such as low bone mineral density (BMD) and hence an increased risk of fractures in later life. Aim To explore the interaction between BMD and lung function, nutrition, and genotype. METHODS: This study was a retrospective audit of 202 children with CF from August 2000 to January 2016 to investigate associations between BMD Z-scores with clinical status, nutrition, and genetics using dual-energy absorptiometry X-ray data from the Royal Children's Hospital Melbourne, Australia. RESULTS: Severity of both lung disease (P < 0.0001) and nutritional status (P < 0.05) was found to be strongly associated with BMD Z-scores. CONCLUSIONS: This is the biggest study to date to provide further evidence that the severity of pulmonary disease is related to BMD in CF patients and therefore screening guidelines for bone health in children with CF should target individuals with the poorest clinical status.

Hospital use in Aboriginal and non-Aboriginal patients with chronic disease.

OBJECTIVE: The objective of this study was to compare rates of hospital utilisation in Aboriginal and non-Aboriginal peoples before and after hospital admission for chronic obstructive pulmonary disease, heart failure and/or type 2 diabetes mellitus. METHODS: This was a longitudinal cohort study from 2002 to 2014, which was conducted in all hospitals in Western Australia. The participants of this study were Aboriginal and non-Aboriginal patients with a principal diagnosis of heart failure, type 2 diabetes or chronic obstructive pulmonary disease, on admission to hospital, where such an event had not occurred in the previous 3 years. Inpatient days and ED presentations were the main outcome measures. RESULTS: Among the patients with chronic disease, Aboriginal people have similar inpatient days for all causes compared to non-Aboriginal people. However, they have much higher ED presentations in comparison. Age of onset of cardinal events occurs 15-20 years earlier in Aboriginal patients with chronic disease. Although age has little influence on ED presentations in non-Aboriginal chronic disease patients, younger Aboriginal people with chronic disease present far more often to ED than older Aboriginal people. CONCLUSIONS: Aboriginal people use health services in a different manner when compared to non-Aboriginal people. In a subset of patients with chronic disease, high use may be reduced with better access to primary healthcare. Policy-makers and healthcare providers should examine healthcare use from primary to tertiary care among the Aboriginal population, with a particular focus on ED presentations; investigate the underlying causes driving specific patterns of health service utilisation among Aboriginal people; and develop interventions to reduce potential deleterious impacts, and enhance the potential benefits, of specific patterns of healthcare use.

Diversity management: the treatment of HIV-positive employees.

Socio-demographic dimensions such as age, gender, sexual orientation, race and ethnicity are commonly included in diversity studies. With a view to helping Asian hospitality managers to manage HIV-positive employees in their workplaces through diversity management (DM) theory, this research extends the boundaries of previous diversity studies by considering Human Immunodeficiency Virus (HIV) infection as a diverse characteristic. Both quantitative and qualitative primary data were collected from purposively selected Asian hospitality managers through postal questionnaire and follow-up telephone interviews. Transformed raw data were analysed using summary statistics and template analysis. Asian hospitality managers agreed that DM would be appropriate in the management of HIV-positive employees and that it could generate substantial benefits for employees and employers. However, they believe that the successful adoption and implementation of DM is not easy; it requires training and, ideally, the recruitment of experienced directors. Nevertheless, Asian hospitality managers are confident that implementing DM to manage HIV-positive employees can enhance tolerance, improve understanding and promote equality. The purposive sampling technique and the small number of respondents have impacted the external validity of the study. However, this exploratory study initiates an equality discussion to include HIV-positive employees in DM discourse beyond antidiscrimination legislation. It also supplements the sparse literature addressing HIV-positive employees in the Asian hospitality workplace. Asian hospitality managers are advised to understand and employ DM to treat HIV-positive employees fairly to overcome hospitality workplace marginalisation, discrimination and stigmatisation.