Acute rheumatic fever (ARF) and its complication rheumatic heart disease (RHD) remain important causes of preventable suffering and death for Māori and Pacific New Zealanders. The rate of new cases of ARF notified in 2016 for Maori 5 to 12 year-olds was 23.4 per 100,000 and for Pacific 5 to 12 year-olds it was 62.9 per 100,000, many times higher than the rates for European/Others. Despite ARF having been largely eradicated in many high-income and upper-middle-income countries, gaps in knowledge of risk factors for ARF and RHD and its pathophysiology severely limit disease prevention and control.
Our goal is to support the design of an optimised, evidence-informed strategy that will contribute to the 'endgame' for ARF and RHD in New Zealand. Specific aims are:
- To construct an economic-epidemiological model of the natural history of ARF and RHD in New Zealand.
- To use this model to estimate the incremental cost-effectiveness of a full range of plausible health sector interventions at the primary, secondary and tertiary prevention levels.
- To investigate the feasibility of economic assessment of primordial prevention for ARF and RHD.
In summary, this study will build an economic-epidemiological model of ARF/RHD, incorporating natural history, using (largely New Zealand) data on disease progression probabilities and the effectiveness of interventions. It will model at the population level the total costs and health outcomes from each of the intervention scenarios, then present the incremental costs and outcomes compared with the status quo. This model will estimate the incremental cost-effectiveness of a full range of plausible interventions across the ARF/RHD causal pathway. It will also consider the feasibility of economic evaluation of primordial interventions for reducing the disease burden. An international advisory committee composed of experts in ARF/RHD and economic evaluation will guide this research. The proposed optimal prevention strategy will be refined through discussions with reference groups representing the views or end-users and affected communities. The study will include the following stages:
- Model construction – we will construct a Markov model of the natural history of ARF/RHD drawing on extensive New Zealand and international data on disease progression probabilities and modelling methods that have been refined by the BODE3 HRC programme.
- Assessing interventions – we will use New Zealand’s increasingly rich data and protective factors for ARF and RHD and the effectiveness of interventions allowing us to consider a broad range of options, including: (a) Primordial prevention, (b) Primary prevention, (c) Secondary prevention, and (d) Tertiary treatment.
- Measuring outcomes, benefits and costs from health system and societal perspectives – we will consider reduction in clinical disease (ARF, RHD, and heart failure), surgical intervention, and mortality, as well as associated economic benefits. Clinical outcomes will be measured in DALYs to enable comparison of interventions that reduce disease morbidity and/or mortality as appropriate. Estimates of healthcare and productivity costs will be obtained from extensive data held by BODE3.
- Analyses, uncertainty and data quality – we will evaluate plausible strategies to determine cost-effectiveness, incorporating an assessment for different population groups (age and ethnicity) and uncertainty in outcomes. Results will be reported from health system and societal perspectives.
- Policy translation – The proposed prevention strategy will be refined through discussions with end users and community representatives and discrete-choice experiments, resulting in further new knowledge and informing an optimal rheumatic fever 'endgame' strategy for New Zealand.
We expect this research will have a rapid impact on health policy and practise in New Zealand. District Heath Boards (DHBs) are grappling with decisions about how best to use limited health resources for ARF/RHD following a large decline in funding allocated to this disease. Consequently, this research is likely to meet an important evidence gap. Given the extreme ethnic inequalities in ARF distribution, any improved allocation of resources to more effective ARF/RHD interventions should reduce ethnic health inequalities. Findings will add to the small international literature on the economic assessment of ARF/RHD interventions. They will also support collaborative links with the END RHD Centre of Research Excellence in Australia, and global efforts to reduce ARF/RHD disease burden.
- Professor Michael Baker
- Dr Julie Bennett
- Dr Matire Harwood, University of Auckland
- Dr Susan Jack
- Dr Giorgi Kvizhinadze
- Mr William Leung
- Dr Jane Oliver, Murdoch Children's Research Institute
- Dr Dianne Sika-Paotonu
This project is funded by the Health Research Council (HRC) of New Zealand (REF 18/079).