2 research outputs found
Understanding the healthcare costs of temperature-related morbidity under the changing climate
Background
Exposure to non-optimum temperature may contribute to a substantial morbidity
and mortality burden to our society. A growing number of studies have investigated
the risks of increasing temperatures on morbidity and health service use. Estimating
the economic burden of treating temperature-attributable emergency department
(ED) presentations and hospital admissions is paramount to better understand the
resource implications of temperature to the healthcare system. As the climate is
shifting towards a warmer temperature, government and public health agencies
demand evidence of future climate-related morbidity burden and economic cost to
design practical guidelines, adaptive strategies, and tailored public health
interventions.
Aims
The overall aim of this thesis was to provide scientific evidence for policymaking
and practical guideline development to reduce the public health impacts and
economic burden associated with extreme temperature and heatwaves. This thesis
encompasses four studies, with specific aims to i) establish the temperaturemorbidity
and temperature-cost relationships; ii) quantify the total ED presentations
and costs attributed to heatwave intensity and heatwave severity; iii) estimate the
current net-, cold-, and heat-attributable ED presentations, hospital admissions,
length of hospital stay (LoS), and associated healthcare costs; and v) estimate future
health and cost burden attributed to projected temperatures under different climate
and population growth scenarios. Methods
Based on the exposure and response variables, the study can be broadly divided into
three parts, namely: ED presentations and ED costs with mean temperatures;
hospital admission, LoS, and associated costs with mean temperatures; and ED
presentations and costs with heatwaves. All the studies in this thesis were conducted
using daily aggregated patients’ data from all public hospitals in Adelaide
metropolitan area, South Australia (SA). Based on the 2016 census, the total
population of the city was nearly 1.3 million. International classifications of
diseases 10th version (ICD-10) was used to identify specific diagnosis groups
including respiratory, renal, mental health disorders, heat-related illnesses (HRI),
ischaemic heart diseases (IHD), and diabetes. These diseases were merged to
increase the statistical power and termed as temperature related diseases (TRDs). A
time-series analysis combined with a distributed lag nonlinear model (DLNM) was
used to estimate the exposure-response relationships and delayed effects
simultaneously. Using the current relationships, future morbidity and cost burdens
of mean temperatures were projected under three representative concentration
pathways (RCPs) (RCP2.6, RCP4.5, and RCP8.5) and medium population growth
scenarios. All costs were calculated in Australian dollars (AU4.7 million (95% eCI: 1.8, 7.5) costs, respectively. Under RCP8.5 and with a constant population, heat-attributable ED
presentations and healthcare costs are projected to increase by 1.5% (95% eCI: 0.8,
2.2) and 2.0% (95% eCI: 1.1, 2.8) during 2054-57, respectively. When population
change is considered, heat-attributable ED presentations and costs would increase
by 1.9% (95% eCI: 0.8, 3.0) and 2.5% (95% eCI: 1.3, 3.7) during 2034-2037 and
by 3.7% (95% eCI: 1.7, 5.6) and 5.0% (95% eCI: 2.6, 7.1) during 2054-2057,
respectively. There may be no change in cold-attributable ED presentations and
costs.
In study 2: Using hospital admission data from 2010-2015, a comprehensive
impact assessment of non-optimum temperature on TRD hospitalisations, LoS, and
healthcare costs showed significant risks associated with heat exposure. During the
baseline period, the net temperature-attributable hospital admissions, LoS, and
associated costs were estimated to be 3,915 cases (95% empirical confidence
interval (eCI): 235, 7,295), 99,766 days (95% eCI: 14,484, 168,457), and AU1,020.3 (95% eCI: 224.9, 1,804.7), costs are in thousands.
The HRI was the disease category contributing most to ED presentations and costs. Age groups ≤ 14 and ≥ 65 years were most susceptible to heat. For the elderly
population, heatwave attributed to 554 (95% eCI: 228, 834) ED presentations and
AU$530.1 (95% eCI: 160.2, 890.4) costs during the study period.
Conclusions
Heat-related risks and attributable ED presentations, hospital admission, LoS, and
associated healthcare costs were dominant during the baseline periods. Young and
old populations were the most vulnerable populations to heatwaves contributing a
higher cost burden to the healthcare system. The projected estimates indicated that
hot ambient temperatures are likely to increase future morbidity and healthcare
costs substantially under all climate change scenarios. The broad implication of this
thesis is to inform relevant stakeholders and provide evidence for policymaking
about the morbidity and economic burden of observed and projected temperature.
The results help to track the future burden of climate change and to develop a range
of climate change mitigation and public health adaptation responses. Moreover, the
results suggest targeted intervention actions such as protecting the vulnerable
population and the need to build the capacity of the health system.Thesis (Ph.D.) -- University of Adelaide, School of Public Health, 202