An investment case for the prevention and management of rheumatic heart disease in the African Union 2021-30: a modelling study

Abstract

Background: Despite declines in deaths from rheumatic heart disease (RHD) in Africa over the past 30 years, it remains a major cause of cardiovascular morbidity and mortality on the continent. We present an investment case for interventions to prevent and manage RHD in the African Union (AU).

Methods: We created a cohort state-transition model to estimate key outcomes in the disease process, including cases of pharyngitis from group A streptococcus, episodes of acute rheumatic fever (ARF), cases of RHD, heart failure, and deaths. With this model, we estimated the impact of scaling up interventions using estimates of effect sizes from published studies. We estimated the cost to scale up coverage of interventions and summarised the benefits by monetising health gains estimated in the model using a full income approach. Costs and benefits were compared using the benefit-cost ratio and the net benefits with discounted costs and benefits.

Findings: Operationally achievable levels of scale-up of interventions along the disease spectrum, including primary prevention, secondary prevention, platforms for management of heart failure, and heart valve surgery could avert 74 000 (UI 50 000-104 000) deaths from RHD and ARF from 2021 to 2030 in the AU, reaching a 30·7% (21·6-39·0) reduction in the age-standardised death rate from RHD in 2030, compared with no increase in coverage of interventions. The estimated benefit-cost ratio for plausible scale-up of secondary prevention and secondary and tertiary care interventions was 4·7 (2·9-6·3) with a net benefit of $2·8 billion (1·6-3·9; 2019 US$) through 2030. The estimated benefit-cost ratio for primary prevention scale-up was low to 2030 (0·2, <0·1-0·4), increasing with delayed benefits accrued to 2090. The benefit-cost dynamics of primary prevention were sensitive to the costs of different delivery approaches, uncertain epidemiological parameters regarding group A streptococcal pharyngitis and ARF, assumptions about long-term demographic and economic trends, and discounting.

Interpretation: Increased coverage of interventions to control and manage RHD could accelerate progress towards eradication in AU member states. Gaps in local epidemiological data and particular components of the disease process create uncertainty around the level of benefits. In the short term, costs of secondary prevention and secondary and tertiary care for RHD are lower than for primary prevention, and benefits accrue earlier.

Funding: World Heart Federation, Leona M and Harry B Helmsley Charitable Trust, and American Heart Association.

Figure 1:. Health impact model structure

Health states are represented by white rectangles (death in grey rectangles) with transitions shown by blue arrows. Green rectangles represent interventions with black arrows showing the pathways on which the interventions act. Medically managed heart failure that no longer meets criteria for heart failure remains in the RHD with heart failure category because it has advanced irreversibly to severe disease. Populations occupy the health states in white and grey rectangles after each step of the model. The health states in the group A streptococcus and ARF portion of the model shown in pink are simplified in this figure, and there are more complex transitions occurring in each model step. The more detailed structure of the model is described in the appendix (pp 4, 8) with labels corresponding to transition probabilities. Postoperative management here is included with heart failure management, because these are services provided by the same providers within the health system in our model of scale-up. ARF=acute rheumatic fever. RHD=rheumatic heart disease.

Figure 2:. Impact of interventions scaled to target coverage on age-standardised rates of incidence, prevalence, and deaths from RHD, 2020–30

Rates age-standardised to 2017 age structure of population in the African Union. Uncertainty intervals in rates reflect uncertainty in underlying epidemiological parameters as well as uncertainty about intervention effects; uncertainty in percent differences primarily reflects uncertainty in intervention effects. RHD=rheumatic heart disease.

Figure 3:. Cost of interventions scaled to target coverage, 2020–30

Costs in 2019 US$. Costs presented for scale-up of all interventions to target coverage. Shared costs for primary and secondary prophylaxis include mass media awareness and education campaign costs and costs of provider education, training, and mentorship to strengthen correct treatment of sore throat, referral of ARF for diagnosis, and administration of secondary prophylaxis at health centres. Shared costs for secondary prophylaxis, heart failure management, and surgery include first referral-level provider training and costs of equipment and supplies. ARF=acute rheumatic fever. RHD=rheumatic heart disease.