Rheumatic heart disease screening, Cancer and Chronic Conditions (C3) research group

About the project

Between 2013 and 2016, our research group collaborated with Auckland District Health Board (ADHB) to perform an evaluation of an echocardiography screening pilot programme which took place over the past several years. The evaluation was part of a larger project relating to rheumatic heart disease being led from ADHB ('The significance of rheumatic heart disease detected by echocardiography').

Our work on this project consisted of multiple components. First, we interviewed the parents of those children who were screened – including those who were found to have cardiac abnormality, and a matched random sample of those who did not – to identify the impact of the screening event. Next, we described active surveillance strategies currently used for patients with sub-clinical and borderline RHD, and describe how these strategies vary nationally and internationally. Then, we quantified the stratum-specific incidence and absolute risk of acute rheumatic fever (ARF) incidence in New Zealand between 2010-2013. Finally, we developed an educational tool aimed at improving sore throat and ARF-specific health literacy among the population groups who are at greatest risk of ARF.

For more information about each component, click on the relevant links below.

• Benefit and Harm of screening and patient outcomes
• Stratum-specific incidence and risk of acute rheumatic fever in NZ
• Active surveillance of patients with sub-clinical RHD
• Ensuring informed choice through health literacy

Benefit and Harm of screening and patient outcomes

The echocardiography screening evaluated in this component of the project was offered to children through their schools, and was looking for instances of undiagnosed rheumatic heart disease among 10-13 year olds. The programme began in 2007 in the South Auckland region, and extended to multiple other regions (with service leaders in these regions leading and facilitating the programme). The latest programme was offered in Porirua in 2012.

Our evaluation aims to identify benefits and harms of this screening from the perspective of the participants and their parents/caregivers. We will interview a number of parents/caregivers, who will serve as the primary informants on behalf of the screened children, in order to further our understanding of the safety of screening for rheumatic heart disease by describing participant experiences and changes in behaviour post-screening.

Using tools from the New Zealand Health Survey, the Child Health Questionnaire and other sources, we measured the following:

• Recall of screening result;
• Levels of anxiety caused by participation in the screening programme;
• Changes in behaviour by the screened child following their diagnosis, particularly participation in physical activities such as sport;
• Known history of ARF/RHD among the a) screened child and b) their family;
• Receipt of follow-up care among those with abnormal results, including antibiotic prophylaxis and additional scans, as well as perceived barriers to follow-up care;
• Health awareness about sore throats, rheumatic fever, and the link between them.”

This work was subsequently published in the International Journal of Cardiology, and you can find that manuscript here

Stratum-specific incidence and risk of acute rheumatic fever in NZ

The population targeted for screening over the past several years were largely those of intermediate school age (10-13 years) who attended schools in the lowest socio-economic areas.1 This targeting was based on the strong association between deprivation and acute rheumatic fever (ARF) incidence; however by using this approach those with other risk factors (most notably Māori or Pacific ethnicity) may not be included if they live in less deprived areas.

Targeting of RHD screening to those with the highest prevalence of ARF will increase the positive predictive value of the screening test and reduce the number needed to screen per definite RHD identified. In order to maximise the efficacy of this targeting, we need to understand more regarding: a) which groups carry the highest burden of disease; b) where they reside; and c) how many people potentially comprise these target groups. For example, Māori and Pacific ethnicity are both strongly associated with ARF incidence independent of deprivation.

To this end, we updated and built-on previous work in this area by estimating the burden of ARF across multiple demographic and geographic strata. This requires the achievement of the following objectives:
1) using literature review, summarise available data regarding the distribution of ARF in New Zealand by ethnicity, age, geographic region and deprivation (NZDep);
2) collect data from hospitalisations (National Minimum Dataset [NMDS], Ministry of Health) and national notifications (EpiSurv, Environmental Science and Research) on all new cases of ARF (2010-2013), including encrypted patient identifier (NHI) and all other available demographic information;
3) quantify the incidence (n) and distribution of ARF separately by geographic region, prioritised ethnicity, age group and deprivation level using census data as our denominator;
4) develop a risk prediction model for the New Zealand context which will allow us to simultaneously combine the effects of our predictors (e.g. ethnicity, deprivation, etc), and to identify groups who are most at risk (and therefore most likely to benefit from RHD screening);
5) using data from the 2013 census, quantify by geographic region the number of people who belong to the target ethnicity / age / deprivation groups (as identified from the risk prediction model).”

Regarding the first three of these objectives, we produced a brief study report: The incidence of acute rheumatic fever in New Zealand (2010-2013) – as well as a letter in the New Zealand Medical Journal. Regarding the last two of these objectives, we produced a manuscript which was subsequently published in Epidemiology and Infection. And you can find that manuscript here.

Active surveillance of patients with sub-clinical RHD

The aim of this component was to describe what is current practice with respect to active surveillance (including echocardiography re-scanning and receipt of secondary prophylaxis) of patients diagnosed with RHD via screening. For those with abnormalities that do not clearly indicate RHD, an active surveillance approach is appealing; follow-up echocardiography along with clinical re-evaluation at various intervals allows clinicians to monitor progression, potentially saving patients from 4-weekly intramuscular antibiotic injections. Such follow-up also provides opportunities for discussion and education regarding primary prevention of rheumatic fever by recognising and treating group A streptococcal infection. To date, actual practise in relation to the follow up of individuals with a positive RHD screen has not be described in detail in New Zealand.

Thus, the objective of this component of our study was to summarise the follow up of children with a positive RHD screening test, including: a) active surveillance of asymptomatic patients with an abnormal echocardiogram following screening; b) ongoing receipt of repeat echocardiography scans; and c) initiation of antibiotic secondary prophylaxis. In addition, we have described active surveillance strategies employed in similar contexts internationally; and finally, we have combined this information to make some recommendations regarding follow-up care for those classified as having sub-clinical or borderline RHD in New Zealand.

We subsequently produced a report that described our observations: The Active Surveillance of Children Diagnosed with Echocardiography-Detected Rheumatic Heart Disease (2007-2012)

Ensuring informed choice through health literacy

Ensuring that screening participants and their families understand the risks and benefits of rheumatic heart disease (RHD) screening to better make an informed choice regarding participation is crucial in ensuring the safety of the screened population. The aim of this component of our study was to develop an educational tool to inform the screened population and their families about the likely balance of benefits, potential harms and uncertainty around RHD screening.

To this end, we designed a one-page learning material (i.e. pamphlet) for circulation among present and future screened populations and their families. This learning material was intended to have a mixture of clinical- and screening-related content, and was constructed with experts from both these fields as well as other relevant parties.

The usefulness of the pamphlet was qualitatively assessed using a focus group of parents. CBG Health Research Ltd. (CBG), an independent provider of public sector surveying with skills in convening focus groups, assisted with identifying and recruiting focus group members from a sample of the target population. We recruited 8 focus group participants; 4 Māori, 3 Pacific and 1 NZ European, to (loosely) reflect the incidence of Acute Rheumatic Fever (ARF) in New Zealand. Following the focus group, CBG produced a report of the group's key findings: CBG Report - Focus Group findings.

Based on the findings of the focus group, several changes were made to the learning material. These changes were documented in a brief report: Brief Study Summary and Discussion of Focus Group Recommendations.

Following these changes, a revised version of the learning material was created – and this final version can be found here: Screening for rheumatic heart disease (RHD): What are the benefits, harms and uncertainties?

Our people

• Jason Gurney; University of Otago, Wellington
• Diana Sarfati; University of Otago, Wellington
• Peter Murray, Hutt Valley District Health Board
• Virginia Signal, University of Otago, Wellington