Background
Ischemic or coronary heart disease (IHD) is a group of health conditions that includes: stable angina, unstable angina, acute myocardial infarction, and sudden cardiac death. IHD has an enormous burden on individuals globally, which has been measured in terms of years of life lost from IHD deaths and years of disability lived with 3 nonfatal IHD sequelae: nonfatal acute myocardial infarction, angina pectoris, and ischemic heart failure. The global burden of IHD increased by 29 million disability-adjusted life-years (DALYs) between 1990 and 2010 – a 29% increase [
1].
Global burden of disease studies project the significant reductions in quantity and quality of life due to IHD at national, regional and global levels. However, national governments and supranational economic/public health organisations (such as the Organisation for Economic Co-operation and Development (OECD) and the World Health Organisation (WHO)) also emphasise the significant impacts of chronic conditions (such as IHD) on productive life years (PLYs) – where lost PLYs due to IHD are defined as
the number of people who are out of the labour force due to IHD on an annual basis [
2] – resulting in indirect costs for individuals (lost income) and the government (extra welfare payments and lost income tax revenue) in addition to direct (healthcare) costs [
3,
4].
The direct health care costs of IHD are larger than the costs for any other chronic disease group [
5,
6]; however, the indirect costs of IHD through lost labour force participation are likely to be equally as large as the direct costs. Initial events of IHD can have a significant impact on the physical and psychological ability of individuals [
7,
8] which may also impact on their ability to remain in the labour force and their economic survival, with these impacts increasing as repeated events occur.
While WHO has defined health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity” for more than 60 years (WHO 1946 in Cowie (2016) [
9]), studies on the impact of chronic conditions on labour force participation have only recently emerged (see, for cardiovascular disease (CVD) costs for Europe, [
10,
11]; and for Australia, [
12,
13]). This is despite the fact that labour force participation is not only important economically but also as an indicator of physical functioning and psychological metrics (such as self-esteem and connectedness) in individuals with chronic conditions [
9].
One of the major challenges facing governments in Australia and elsewhere is the ageing population, which leads to increased demand for health care but ageing of the workforce also impacts on the income tax to fund health care and other essential services. For these reasons, the Australian Government (and others) have implemented a range of polices to encourage older workers (also known as mature age workers and typically defined as being 45–64 years of age by the Australian Bureau of Statistics although other agencies sometimes use 50–64 or 55–64 years [
14]) to remain longer in the work force, including raising the official retirement age. However, these polices may not be sufficient to ensure that people remain longer in the work force if their ill-health is preventing them from doing so.
Since the incidence of IHD increases with age [
5,
15], older workers (45–64 years) are more likely to incur disability related to these events which impacts on their working capacity. In our previous study, we found that CVD (includes IHD) has a significant and enduring impact on the labour force participation of older workers (45–64 years). In particular, we estimated that 7% of older workers were out of the labour force due to IHD in both 2010 (25,000) and 2030 (30,000), making IHD the fourth most common chronic disease causing early retirement among this age group [
2]. Workers with CVD are also more likely to have their employment affected by disease-related outcomes [
15]. Many countries are confronted with similar challenges with regard to the ageing workforce, and hence have the same need to plan for increased economic losses due to chronic diseases such as IHD [
8,
9,
16].
In our previous study, we projected the PLYs lost due to chronic health conditions (including IHD) for people aged 45–64 years [
2]. The aim of this study is to project the indirect costs of IHD among Australians aged 45–64 years from 2015 to 2030 using Australia’s first microsimulation model on the economic impacts of ill-health, Health&WealthMOD2030. It is the first study in Australia and internationally to project the indirect costs of IHD based on the individual’s lost labour force participation and lost income (as opposed to average earnings); the government’s costs through lost income tax revenue and extra welfare payments; and society’s cost through lost GDP due to lost PLYs from IHD, out to 2030. While developing the modelling infrastructure used in this study is a large undertaking, many countries have models using similar methods, and others may see the use for investing in developing these models, upon reading our paper. Additionally, there has been a recent change in the United States’ recommendations on cost-effectiveness analysis which emphasises moving from not including productivity costs to now including them [
17,
18]. This change highlights a particular need for the type of cost inputs that the current study presents.
Discussion
The national impacts of IHD through the loss of labour force participation among 45–64 year olds was projected to increase over the next 15 years, with a 62.27% increase in lost personal income, which grew faster than the 43.91% growth in welfare payments due to the indexation of welfare payments being less than expected wages growth; and a 43.31% increase in lost GDP. To our knowledge, these are the first projections of the indirect costs of IHD in Australia.
The key advantage of developing large-scale microsimulation models based on unit record data from nationwide surveys undertaken by a national Bureau of Statistics is that they can be used to generate reliable information about the size and characteristics of subpopulations [
35]. This is due to the fact that they can imitate the heterogeneity in the population by means of the national sample surveys. By reweighting the input data, it is also possible to project this information several years ahead. Other advantages are that microsimulation models can be built to replicate the sophistication of policy settings and/or financial and other systems and thereby be used to predict outcomes arising from changes to these settings and/or systems. This is achieved through setting up various “what if” scenarios with the results describing what the outcomes are, under certain assumptions, for individuals or subgroups [
36]. The primary objective of Health&WealthMOD2030 is to project the number of Australians aged 45–64 years with various chronic diseases (such as IHD) and the costs of non-participation in the labour force due to ill-health out to 2030, which will enable the government to better prepare for future healthcare needs.
This study has some limitations. One is that the results from Health&WealthMOD2030 are based on SDAC respondents’ self-reported work status and chronic conditions, though self-reported employment status and health are regarded as reliable measures for costing studies [
37,
38]. Another is that the SDACs are cross-sectional surveys; however, some sections of the surveys were designed in a way that enables identification of causal relationships. For example, the SDACs have ‘own ill-health or disability’ as a category for the main reason people are out of the labour force which made it possible to identify workers who retired early due to their ill-health in this study. Another is that the static microsimulation modelling method and the SDACs 2003 and 2009 do not capture or model mortality, and therefore the study did not estimate the impact of mortality on labour force participation.
Few studies have examined the indirect costs of IHD in the same level of detail as in this study. Guico-Pabia et al. (2001) estimated the indirect costs of IHD using the human capital approach (as in this study), and adopting the perspective of the employer in private industry in the United States. Several national databases were explored, and the indirect cost consisted of the costs due to morbidity (lost productivity, idle assets, and nonwage factors resulting from absenteeism) and mortality (costs of replacing and retraining workers). The total indirect cost of IHD to employers in private industry was $182.74 per enrolee; and 95% of the indirect cost was the consequence of lost work due to morbidity costs [
39]. In Australia, Deloitte Access Economics (2011) estimated the costs of lost labour force participation and early mortality due to acute coronary syndrome (a subset of IHD) to be $2.1 billion across all age groups in 2010 [
5]. However, these studies have only used average earnings for the population to estimate lost productivity and have not estimated the costs to the individual nor projected costs into the future; and they have not estimated taxes and welfare costs.
The current study has quantified the national costs of lost PLYs due to IHD to the Australian Government in terms of lost income tax revenue and increased welfare payments, and we would argue that prevention strategies for IHD will likely be more cost-effective when these additional costs are also considered. There are many primary and secondary prevention strategies (lifestyle modifications and pharmacological treatments [
40], as well as population-level interventions (such as fiscal interventions to improve diets [
41] and improving urban infrastructure for active transport [
42]) that have been shown to be effective for IHD. Although some of the strategies that reduce the incidence of IHD may be considered “expensive” from the perspective of the national health system, it is highly likely that if productivity losses were included in economic evaluations, they would demonstrate cost-effectiveness (see, for example, Grover et al. (2003) [
43]). The productivity impact is particularly important for governments facing severe deficits and in need of implementing resource effective strategies to prevent and treat chronic conditions [
44].
Lost productive life years (PLYs) is a relatively new metric of disease burden and one that we have valued in terms of lost income to individuals, extra welfare payments and lost tax revenue to the government, and lost GDP to society. Both this measure and its multidimensional valuation are not considered in most health economics research. To widen the usefulness of the valuation of lost PLYs due to chronic diseases, we have valued these lost PLYs from the different perspectives of the patient, the government, and society. Undoubtedly, the inclusion of indirect costs either as a benefit (denominator of the ICER) or cost (numerator of the ICER) has an impact on cost-effectiveness analyses. The recent shift in the United States’ recommendations on cost effectiveness analysis emphasises a change from not including productivity costs to now including them [
17,
18]. This shift in policy highlights a particular need for the cost inputs presented in this paper.
In addition to the costs to governments, there are significant costs to individuals who have exited from the labour force due to IHD. The reduced income as a result of exiting from the labour force is likely to reduce these individuals’ living standards – lost income among those with ill-health has been associated with a higher risk of falling below the poverty line [
45] and having inadequate savings for retirement. [
46] In Australia, it has been reported that older workers who have retired early due to CVD have significantly less personal wealth, and significantly lower savings by the time they reach the traditional retirement age of 65 years than those who remained healthy and were able to stay in the labour force [
12,
13].
Working capacity is currently an overlooked aspect of recovery for heart failure, and indeed IHD or CVD more generally [
9]. Rørth et al. (2016) examined the likelihood of people returning to work following first-time hospitalisation for heart failure using a Danish cohort. They suggest there are a range of reasons why return to work rates are low for people who have experienced heart failure, including the physical functioning limitations of the disease or comorbidities and the psychological effects of having been diagnosed with heart failure. Cowie (2016) maintains that the healthcare teams assisting patients who have experienced heart failure often do not consider the patient’s return to work to be possible, they are apprehensive about the risks for patients returning to work, or do not have competence in employment counselling or restoration. To promote the patient’s working capacity as a central and desirable feature of rehabilitation, Cowie (2016) argues that working capacity would need to be considered at each point in the patient’s journey from the first-time hospitalisation to returning to work, and for there to be ongoing engagement from the relevant stakeholders (i.e. the patient, their family, and their employer) at these different points [
9]. Recent studies from a cross-sectional survey of people on sick leave due to heart failure in Sweden suggest that constructive encounters between healthcare professionals and social insurance officers are associated with patient’s having an improved perception of their likely ability to return to work [
47,
48].
In order to minimise the costs of lost PLYs due to IHD reported in this paper, greater investment in IHD prevention and other strategies that include working capacity as a central feature are recommended. This approach aligns with the health platform of the Australian Government which emphasises that better prevention and/or treatment strategies for chronic disease can not only improve health outcomes for individuals but economic outcomes for individuals and the nation [
34,
49].
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