The End Rheumatic Heart Disease in Australia Study of Epidemiology (ERASE) Project: data sources, case ascertainment and cohort profile

Excess Deaths Associated with Rheumatic Heart Disease, Australia, 2013-2017

During 2013-2017, the mortality rate ratio for rheumatic heart disease among Indigenous versus non-Indigenous persons in Australia was 15.9, reflecting health inequity. Using excess mortality methods, we found that deaths associated with rheumatic heart disease among Indigenous Australians were probably substantially undercounted, affecting accuracy of calculations based solely on Australian Bureau of Statistics data.

The evidence that rheumatic heart disease control programs in Australia are making an impact

OBJECTIVE

Rheumatic heart disease (RHD) comprises heart-valve damage caused by acute rheumatic fever (ARF). The Australian Government Rheumatic Fever Strategy funds RHD Control Programs to support detection and management of ARF and RHD. We assessed epidemiological changes during the years of RHD Control Program operation.

METHODS

Linked RHD register, hospital and death data from four Australian jurisdictions were used to measure ARF/RHD outcomes between 2010 and 2017, including: 2-year progression to severe RHD/death; ARF recurrence; secondary prophylaxis delivery and earlier disease detection.

RESULTS

Delivery of secondary prophylaxis improved from 53% median proportion of days covered (95%CI: 46-61%, 2010) to 70% (95%CI: 71-68%, 2017). Secondary prophylaxis adherence protected against progression to severe RHD/death (hazard ratio 0.2, 95% CI 0.1-0.8). Other measures of program effectiveness (ARF recurrences, progression to severe RHD/death) remained stable. ARF case numbers and concurrent ARF/RHD diagnoses increased.

CONCLUSIONS

RHD Control Programs have contributed to major success in the management of ARF/RHD through increased delivery of secondary prevention yet ARF case numbers, not impacted by secondary prophylaxis and sensitive to increased awareness/surveillance, increased.

IMPLICATIONS FOR PUBLIC HEALTH

RHD Control Programs have a major role in delivering cost-effective RHD prevention. Sustained investment is needed but with greatly strengthened primordial and primary prevention.

Rheumatic heart disease mortality in Indigenous and non-Indigenous Australians between 2010 and 2017

OBJECTIVES

To generate contemporary age-specific mortality rates for Indigenous and non-Indigenous Australians aged <65 years who died from rheumatic heart disease (RHD) between 2013 and 2017, and to ascertain the underlying causes of death (COD) of a prevalent RHD cohort aged <65 years who died during the same period.

METHODS

For this retrospective, cross-sectional epidemiological study, Australian RHD deaths for 2013-2017 were investigated by first, mortality rates generated using Australian Bureau of Statistics death registrations where RHD was a coded COD, and second COD analyses of death records for a prevalent RHD cohort identified from RHD register and hospitalisations. All analyses were undertaken by Indigenous status and age group (0-24, 25-44, 45-64 years).

RESULTS

Age-specific RHD mortality rates per 100 000 were 0.32, 2.63 and 7.41 among Indigenous 0-24, 25-44 and 45-64 year olds, respectively, and the age-standardised mortality ratio (Indigenous vs non-Indigenous 0-64 year olds) was 14.0. Within the prevalent cohort who died (n=726), RHD was the underlying COD in 15.0% of all deaths, increasing to 24.6% when RHD was included as associated COD. However, other cardiovascular and non-cardiovascular conditions were the underlying COD in 34% and 43% respectively.

CONCLUSION

Premature mortality in people with RHD aged <65 years has approximately halved in Australia since 1997-2005, most notably among younger Indigenous people. Mortality rates based solely on underlying COD potentially underestimates true RHD mortality burden. Further strategies are required to reduce the high Indigenous to non-Indigenous mortality rate disparity, in addition to optimising major comorbidities that contribute to non-RHD mortality.

Evolution of non-fatal burden estimates for cardiovascular disease in Australia: a comparison of national and state-wide methodology of burden of disease

Objective Burden of disease studies measure the impact of disease at the population level;however, methods and data sources for estimates of prevalence vary. Using a selection of cardiovascular diseases, we aimed to describe the implications of using different disease models and linked administrative data on prevalence estimation within three Australian burden of disease studies. Methods Three different methods (A = 2011 Australian Burden of Disease Study; B = 2015 Australian Burden of Disease Study; C = 2015 Western Australian Burden of Disease Study), which used linked data, were used to compare prevalence estimates of stroke, aortic aneurysm, rheumatic valvular heart disease (VHD) and non-rheumatic VHD. We applied these methods to 2015 Western Australian data, and calculated crude overall and age-specific prevalence for each condition. Results Overall, Method C produced estimates of cardiovascular prevalence that were lower than the other methods, excluding non-rheumatic VHD. Prevalence of acute and chronic stroke was up to one-third higher in Method A and B compared to Method C. Aortic aneurysms had the largest change in prevalence, with Method A producing an eight-fold higher estimate compared to Method C, but Method B was 10-20% lower. Estimates of VHD varied dramatically, with an up to six-fold change in prevalence in Method C due to substantial changes to disease models and the use of linked data. Conclusions Prevalence estimates require the best available data sources, updated disease models and constant review to inform government policy and health reform. Availability of nation-wide linked data will markedly improve future burden estimates.

Long-term outcomes following rheumatic heart disease diagnosis in Australia

Aims 

Rheumatic heart disease (RHD) is a major contributor to cardiac morbidity and mortality globally. This study aims to estimate the probability and predictors of progressing to non-fatal cardiovascular complications and death in young Australians after their first RHD diagnosis.

Methods and results 

This retrospective cohort study used linked RHD register, hospital, and death data from five Australian states and territories (covering 70% of the whole population and 86% of the Indigenous population). Progression from uncomplicated RHD to all-cause death and non-fatal cardiovascular complications (surgical intervention, heart failure, atrial fibrillation, infective endocarditis, and stroke) was estimated for people aged <35 years with first-ever RHD diagnosis between 2010 and 2018, identified from register and hospital data. The study cohort comprised 1718 initially uncomplicated RHD cases (84.6% Indigenous; 10.9% migrant; 63.2% women; 40.3% aged 5–14 years; 76.4% non-metropolitan). The composite outcome of death/cardiovascular complication was experienced by 23.3% (95% confidence interval: 19.5–26.9) within 8 years. Older age and metropolitan residence were independent positive predictors of the composite outcome; history of acute rheumatic fever was a negative predictor. Population group (Indigenous/migrant/other Australian) and sex were not predictive of outcome after multivariable adjustment.

Conclusion 

This study provides the most definitive and contemporary estimates of progression to major cardiovascular complication or death in young Australians with RHD. Despite access to the publically funded universal Australian healthcare system, one-fifth of initially uncomplicated RHD cases will experience one of the major complications of RHD within 8 years supporting the need for programmes to eradicate RHD.

Period Prevalence of Rheumatic Heart Disease and the Need for a Centralized Patient Registry in American Samoa, 2016 to 2018

Background

Rheumatic heart disease (RHD) is a severe, chronic complication of acute rheumatic fever, triggered by group A streptococcal pharyngitis. Centralized patient registries are recommended for RHD prevention and control, but none exists in American Samoa. Using existing RHD tracking systems, we estimated RHD period prevalence and the proportion of people with RHD documented in the electronic health record.

Methods and Results

RHD cases were identified from a centralized electronic health record system, which retrieved clinical encounters with RHD International Classification of Diseases, Tenth Revision, Clinical Modification (ICD‐10‐CM) codes, clinical problem lists referencing RHD, and antibiotic prophylaxis administration records; 3 RHD patient tracking spreadsheets; and an all‐cause mortality database. RHD cases had ≥1 clinical encounter with RHD ICD‐10‐CM codes, a diagnostic echocardiogram, or RHD as a cause of death, or were included in RHD patient tracking spreadsheets. Period prevalence per 1000 population among children aged <18 years and adults aged ≥18 years from 2016 to 2018 and the proportion of people with RHD with ≥1 clinical encounter with an RHD ICD‐10‐CM code were estimated. From 2016 to 2018, RHD was documented in 327 people (57.2%: children aged <18 years). Overall RHD period prevalence was 6.3 cases per 1000 and varied by age (10.0 pediatric cases and 4.3 adult cases per 1000). Only 67% of people with RHD had ≥1 clinical encounter with an RHD ICD‐10‐CM code.

Conclusions

RHD remains a serious public health problem in American Samoa, and the existing electronic health record does not include all cases. A centralized patient registry could improve tracking people with RHD to ensure they receive necessary care.

Morbidity and mortality of rheumatic heart disease and acute rheumatic fever in the inpatient setting in Timor-Leste

AIM

To describe the clinical features, treatment and outcomes of acute rheumatic fever (ARF) and rheumatic heart disease (RHD) in children admitted to the national referral hospital in Dili, Timor-Leste.

METHODS

This prospective study documented cases of ARF and RHD in children aged 14 years and under who were admitted between June 2017 and May 2019. ARF was diagnosed using an adapted version of the 2015 Jones criteria and presumed (rather than proven) exposure to group A Streptococcus. Clinical and echocardiographic findings, comorbidities and discharge outcomes are reported.

RESULTS

A total of 63 patients were admitted with ARF or RHD; 54 were diagnosed with RHD for the first time. Median age was 11 years (range 3-14); 48% were female. Of those with echocardiograms, 56/58 had RHD, 55/56 (98%) had mitral regurgitation (37/55 (67%) severe), 11/56 (20%) had mitral stenosis and 43/56 (77%) had aortic regurgitation. Left ventricular dysfunction (55%), pulmonary hypertension (64%) and cardiac failure (78%) were common. Four (6%) patients died in hospital, and 30/59 (51%) of surviving patients were lost to follow up.

CONCLUSIONS

Community echocardiography screening has reported a high prevalence of undetected mild to moderate cases of RHD in Timor-Leste, whereas this hospital study documents mostly severe disease among hospitalised patients with a high case fatality rate and loss to follow up. RHD is a significant health problem in Timor-Leste and improved recognition and diagnosis, as well as effective delivery of treatment and follow-up are imperative.

Improving the well-being for young people living with rheumatic heart disease: A peer support pilot program through Danila Dilba Health Service

ISSUE ADDRESSED

Aboriginal and Torres Strait Islander peoples in Australia have an inequitable burden of acute rheumatic fever (ARF) and rheumatic heart disease (RHD), concentrated among young people and necessitating ongoing medical care during adolescence. There is an unmet need for improved well-being and support for these young people to complement current biomedical management.

METHODS

This pilot program initiative aimed to determine the suitability and appropriate format of an ongoing peer support program to address the needs of young people living with RHD in urban Darwin.

RESULTS

Five participants took part in three sessions. Findings demonstrated the peer-support setting was conducive to offering support and enabled participants to share their experiences of living with RHD with facilitators and each other. Satisfaction rates for each session, including both educational components and support activities, were high.

CONCLUSIONS

Learnings from the pilot program can inform the following elements of an ongoing peer-support program: characteristics of co-facilitators and external presenters; program format and session outlines; possible session locations; and resourcing. SO WHAT?: Peer support programs for chronic conditions have demonstrated a wide range of benefits including high levels of satisfaction by participants, improved social and emotional well-being and reductions in patient care time required by health professionals. This pilot program demonstrates the same benefits could result for young people living with RHD.

The "Cairo Accord"- Towards the Eradication of RHD: An Update

Rheumatic heart disease (RHD) is the most common cause of acquired heart disease in children and young adults. It continues to be prevalent in many low- and middle-income countries where it causes significant morbidity and mortality. Following the 2017 Cairo conference "Rheumatic Heart Disease: from Molecules to the Global Community," experts from 21 countries formulated an approach for addressing the problem of RHD: "The Cairo Accord on Rheumatic Heart Disease." The Accord attempts to set policy priorities for the eradication of acute rheumatic fever (ARF) and RHD and builds on a recent series of policy initiatives and calls to action. We present an update on the recommendations of the Cairo Accord and discuss recent progress toward the eradication of RHD, including contributions from our own Aswan Rheumatic Heart Disease Registry (ARGI).

Pediatric rheumatic carditis in Italy and Rwanda: The same disease, different socio-economic settings

BACKGROUND

Acute Rheumatic Fever and Rheumatic Heart Disease are the leading cause of acquired heart disease in Low-Income Countries, and a common cause in High-Income Countries. We compared rheumatic carditis, its echocardiographic presentation at diagnosis and its progression in Italy and Rwanda.

METHODS

Retrospective study including all consecutive patients diagnosed with rheumatic carditis in an Italian (IT) and two Rwandan Hospitals (RW). Echocardiography was performed at diagnosis and three follow-up visits. Baseline characteristics, history of primary and secondary prophylaxis and cardiovascular complications data were collected.

RESULTS

Seventy-nine and 135 patients were enrolled in IT and RW, respectively. Mitral regurgitation was the most common lesion (IT: 70%, RW: 96%) in both cohorts; mixed valve lesions and severe lesions were more prevalent in RW. Age at diagnosis (IT: 8.4 ± 2.9 yrs.; RW: 11.1 ± 2.7 yrs.; P < 0.001), adherence to secondary prophylaxis (IT: 99%; RW: 48%; P < 0.001) and history of primary prophylaxis (IT: 65%; RW: 6%; P < 0.001) were different. During the follow-up, native valve lesions completely resolved in 38% of IT and in 2% of RW patients (P < 0.001). By contrast, cardiac surgery was performed in 31% of RW and 5% of IT patients (P < 0.001). Cardiovascular complications and death were only observed in RW.

CONCLUSIONS

The more severe cardiac involvement, the higher rate of valve surgery, CV complications and deaths in RW, could be due to delayed diagnosis and treatment, scarce adherence to secondary prophylaxis and differences in social determinants of health.

Reducing antibiotic prescriptions in children is not associated with higher rate of complications

Acute otitis media (AOM) and sore throat are common reasons for antibiotic prescription in children. Starting from 2007, evidence-based guidelines and other multifaceted improvement activities (ProBA project) were implemented in Emilia-Romagna, a northern Italian region. Antibiotic prescription rate in the region decreased with time (37% relative reduction from 2005 to 2019). Within the ProBA project, this retrospective observational study, including all hospitals of the region, aims to assess if lower rate of antibiotic prescription was associated with an increased rate of acute mastoiditis and acute rheumatic fever (ARF). Hospital admission rates for acute mastoiditis and ARF from 2005 to 2019 were calculated using ICD-9 codes. Hospital intervention rates for myringotomy, incision of mastoid, and mastoidectomy were also assessed. A comparison with antibiotic prescription rate in the pediatric population was performed. Data were gathered using administrative databases and trends were calculated using Poisson regression. During the study period, rate of mastoiditis and similar diagnosis declined from 54.1 to 33.6 per 100.000 (β coefficient = - 0.047, p value < 0.001) and rate of surgical treatment from 134.6 to 89.6 per 100.000 (β coefficient = - 0.036, p value < 0.001), whereas rate of ARF remained stable at around 4.4-4.8 per 100.000 (β coefficient = - 0.009, p value = 0.472).Conclusion: ProBA project implementation-recommending 5 days of amoxicillin for AOM when needed and 6 days of amoxicillin when streptococcal pharyngitis is detected-was associated with a reduced antibiotic use without an increase of complications. What is Known: • Acute otitis media (AOM) and streptococcal pharyngitis are common pediatric infections and frequent cause of antibiotics prescription. • Fear of rare complications like mastoiditis and acute rheumatic fever can hinder health professionals' compliance with evidence-based guideline. What is New: • Guidelines recommending a short course of antibiotics for AOM and streptococcal pharyngitis are associated with reduced antibiotic prescriptions and no increase of complications. • Analysis based on administrative databases is useful for monitoring projects and supporting health professionals in complying with guidelines.

Understanding valvular heart disease in the dental setting

BACKGROUND

Limited evidence is available regarding dentists' knowledge and interpretation of infective endocarditis (IE) prophylaxis guidelines. The aim of this study was to determine understanding and management of rheumatic and non-rheumatic valvular heart disease (VHD) in the dental setting in Western Australia (WA).

METHODS

A cross-sectional survey of dentists within Perth utilized an online Qualtrics questionnaire developed after consultation with stakeholders. A sampling frame was compiled from the Australian Health Practitioner Regulation Agency with contact details obtained from the White Pages (online), using five quintiles of Socio-Economic Indexes for Areas according to dentist's place of practice.

RESULTS

Of 41 (13.7% of 300 approached) dentists completing the survey (95.1% general dentists, mean years of practice = 15.6), 90.2% reported following the Australian Therapeutic Guidelines (ATG) regarding IE antibiotic prophylaxis in VHD. Most (92.7%) were unaware of the rheumatic heart disease (RHD) control program. Nearly all participants indicated prophylaxis for clearly invasive procedures such as tooth extraction (100.0%) and periodontal surgery (95.1%). Many dentists made the decision to prescribe antibiotics themselves (36.6%).

CONCLUSIONS

The majority of dentists followed the ATG's IE prophylaxis recommendations for cardiac lesions and dental procedures. There was limited knowledge of the national RHD guidelines and the WA RHD control program.

Ending rheumatic heart disease in Australia: the evidence for a new approach

■The RHD Endgame Strategy: the blueprint to eliminate rheumatic heart disease in Australia by 2031 (the Endgame Strategy) is the blueprint to eliminate rheumatic heart disease (RHD) in Australia by 2031. Aboriginal and Torres Strait Islander people live with one of the highest per capita burdens of RHD in the world. ■The Endgame Strategy synthesises information compiled across the 5-year lifespan of the End Rheumatic Heart Disease Centre of Research Excellence (END RHD CRE). Data and results from priority research projects across several disciplines of research complemented literature reviews, systematic reviews and narrative reviews. Further, the experiences of those working in acute rheumatic fever (ARF) and RHD control and those living with RHD to provide the technical evidence for eliminating RHD in Australia were included. ■The lived experience of RHD is a critical factor in health outcomes. All future strategies to address ARF and RHD must prioritise Aboriginal and Torres Strait Islander people's knowledge, perspectives and experiences and develop co-designed approaches to RHD elimination. The environmental, economic, social and political context of RHD in Australia is inexorably linked to ending the disease. ■Statistical modelling undertaken in 2019 looked at the economic and health impacts of implementing an indicative strategy to eliminate RHD by 2031. Beginning in 2019, the strategy would include: reducing household crowding, improving hygiene infrastructure, strengthening primary health care and improving secondary prophylaxis. It was estimated that the strategy would prevent 663 deaths and save the health care system $188 million. ■The Endgame Strategy provides the evidence for a new approach to RHD elimination. It proposes an implementation framework of five priority action areas. These focus on strategies to prevent new cases of ARF and RHD early in the causal pathway from Streptococcus pyogenes exposure to ARF, and strategies that address the critical systems and structural changes needed to support a comprehensive RHD elimination strategy.

Contemporary trends in surgical rheumatic valve disease in a Caribbean nation

BACKGROUND

Clinical practice suggests that rheumatic heart disease (RHD) represents a significant public health challenge in the Caribbean region where advanced disease appears early often leading to surgical intervention. We aimed to determine the burden of RHD and type of procedure among patients undergoing valve surgery in the Dominican Republic (DR).

METHODS

Demographic, clinical and procedural data of all subjects intervened between January 2014 and December 2018 were obtained including valve disorder, anatomic location and type of surgery. Correlation coefficients were used to assess yearly trends of RHD among the 7 cardiovascular surgical centers in the country.

RESULTS

Of 1626 valvular surgeries performed, 733 (45%) corresponded to RHD; 55% female patients, age 50 ± 11 (6-72) years; involving mitral 458 (63%); mitral + aortic 139 (19%); aortic 105 (14%); mitral + tricuspid 31 (4%); 95% prosthetic replacement and 5% mitral/tricuspid repairs. Mean proportion of RHD valve procedures per center for the study period was 53 ± 34%. Age-adjusted analysis showed an overall upwards trend in RHD valvular surgery (mean annual increment of 50 ± 40%, P = 0.01).

CONCLUSIONS

Despite inter-center variability, rates of surgical RHD in the DR increased during the last 5 years affecting a relatively young population. Mitral involvement was the predominant lesion and prosthetic replacement the leading procedure. These data may guide local and regional institutions and policy makers towards the implementation of cost-effective initiatives against RHD.

The use of cardiac valve procedures for rheumatic heart disease in Australia; a cross-sectional study 2002-2017

Background

Australia, although a high income economy, carries a significant burden of rheumatic heart disease (RHD). Acute rheumatic fever (ARF) and RHD are endemic in the Indigenous population. Immigrants from low/lower-income countries (‘non-Indigenous high-risk’) are also at increased risk compared with ‘non-Indigenous low-risk’ Australians. This study describes the utilisation of surgical and percutaneous procedures for RHD-related valve disease among patients aged less than 50 years, from 2002 to 2017.

Methods

A descriptive study using data from the ‘End RHD in Australia: Study of Epidemiology (ERASE) Project’ linking RHD Registers and hospital inpatient data from five states/territories, and two surgical databases. Trends across three-year periods were determined and post-procedural all-cause 30-day mortality calculated.

Results

A total of 3900 valves interventions were undertaken in 3028 procedural episodes among 2487 patients. Over 50% of patients were in the 35–49 years group, and 64% were female. Over 60% of procedures for 3-24 year-olds were for Indigenous patients. There were few significant changes across the study period other than downward trends in the number and proportion of procedures for young Indigenous patients (3–24 years) and ‘non-Indigenous/low risk’ patients aged ≥35 years. Mitral valve procedures predominated, and multi-valve interventions increased, including on the tricuspid valve. The majority of replacement prostheses were mechanical, although bioprosthetic valve use increased overall, being highest among females <35 years and Indigenous Australians. All-cause mortality (n = 42) at 30-days was 1.4% overall (range 1.1–1.7), but 2.0% for Indigenous patients.

Conclusions

The frequency of cardiac valve procedures, and 30-day mortality remained steady across 15 years. Some changes in the distribution of procedures in population groups were evident. Replacement procedures, the use of bioprosthetic valves, and multiple-valve interventions increased. The challenge for Australian public health officials is to reduce the incidence, and improve the early detection and management of ARF/RHD in high-risk populations within Australia.

•

Epidemic RHD in Indigenous Australians drives RHD-related cardiac valve procedures.

•

30-day mortality post-procedural is low in those under 50 years.

•

Bioprosthetic valve replacements higher in young women, and increasing in older patients.

Contemporary Incidence and Prevalence of Rheumatic Fever and Rheumatic Heart Disease in Australia Using Linked Data: The Case for Policy Change

Background In 2018, the World Health Organization prioritized control of acute rheumatic fever (ARF) and rheumatic heart disease (RHD), including disease surveillance. We developed strategies for estimating contemporary ARF/RHD incidence and prevalence in Australia (2015-2017) by age group, sex, and region for Indigenous and non-Indigenous Australians based on innovative, direct methods. Methods and Results This population-based study used linked administrative data from 5 Australian jurisdictions. A cohort of ARF (age <45 years) and RHD cases (<55 years) were sourced from jurisdictional ARF/RHD registers, surgical registries, and inpatient data. We developed robust methods for epidemiologic case ascertainment for ARF/RHD. We calculated age-specific and age-standardized incidence and prevalence. Age-standardized rate and prevalence ratios compared disease burden between demographic subgroups. Of 1425 ARF episodes, 72.1% were first-ever, 88.8% in Indigenous people and 78.6% were aged <25 years. The age-standardized ARF first-ever rates were 71.9 and 0.60/100 000 for Indigenous and non-Indigenous populations, respectively (age-standardized rate ratio=124.1; 95% CI, 105.2-146.3). The 2017 Global Burden of Disease RHD prevalent counts for Australia (<55 years) underestimate the burden (1518 versus 6156 Australia-wide extrapolated from our study). The Indigenous age-standardized RHD prevalence (666.3/100 000) was 61.4 times higher (95% CI, 59.3-63.5) than non-Indigenous (10.9/100 000). Female RHD prevalence was double that in males. Regions in northern Australia had the highest rates. Conclusions This study provides the most accurate estimates to date of Australian ARF and RHD rates. The high Indigenous burden necessitates urgent government action. Findings suggest RHD may be underestimated in many high-resource settings. The linked data methods outlined here have potential for global applicability.

Stroke incidence and subtypes in Aboriginal people in remote Australia: a healthcare network population-based study

OBJECTIVES

We aimed to compare the incidence, subtypes and aetiology of stroke, and in-hospital death due to stroke, between Aboriginal and non-Aboriginal people in Central Australia, a remote region of Australia where a high proportion Aboriginal people reside (40% of the population). We hypothesised that the rates of stroke, particularly in younger adults, would be greater in the Aboriginal population, compared with the non-Aboriginal population; we aimed to elucidate causes for any identified disparities.

DESIGN

A retrospective population-based study of patients hospitalised with stroke within a defined region from 1 January 2011 to 31 December 2014.

SETTING

Alice Springs Hospital, the only neuroimaging-capable acute hospital in Central Australia, serving a network of 50 healthcare facilities covering 672 000 km².

PARTICIPANTS

161 residents (63.4% Aboriginal) of the catchment area admitted to hospital with stroke.

PRIMARY AND SECONDARY OUTCOME MEASURES

Rates of first-ever stroke, overall (all events) stroke and in-hospital death.

RESULTS

Of 121 residents with first-ever stroke, 61% identified as Aboriginal. Median onset-age (54 years) was 17 years younger in Aboriginal patients (p<0.001), and age-standardised stroke incidence was threefold that of non-Aboriginal patients (153 vs 51 per 100 000, incidence rate ratio 3.0, 95% CI 2 to 4). The rate ratios for the overall rate of stroke (first-ever and recurrent) were similar. In Aboriginal patients aged <55 years, the incidence of ischaemic stroke was 14-fold greater (95% CI 4 to 45), and intracerebral haemorrhage 19-fold greater (95% CI 3 to 142) than in non-Aboriginal patients. Crude prevalence of diabetes mellitus (70.3% vs 34.0%, p<0.001) and hypercholesterolaemia (68.9% vs 51.1%, p=0.049) was greater, and age-standardised in-hospital deaths were fivefold greater (35 vs 7 per 100 000, 95% CI 2 to 11) in Aboriginal patients than in non-Aboriginal patients.

CONCLUSIONS

Stroke incidence (both subtypes) and in-hospital deaths for remote Aboriginal Australians are dramatically greater than in non-Aboriginal people, especially in patients aged <55 years.

Case Ascertainment on Australian Registers for Acute Rheumatic Fever and Rheumatic Heart Disease

In Australia, disease registers for acute rheumatic fever (ARF) and rheumatic heart disease (RHD) were previously established to facilitate disease surveillance and control, yet little is known about the extent of case-ascertainment. We compared ARF/RHD case ascertainment based on Australian ARF/RHD register records with administrative hospital data from the Northern Territory (NT), South Australia (SA), Queensland (QLD) and Western Australia (WA) for cases 3-59 years of age. Agreement across data sources was compared for persons with an ARF episode or first-ever RHD diagnosis. ARF/RHD registers from the different jurisdictions were missing 26% of Indigenous hospitalised ARF/RHD cases overall (ranging 17-40% by jurisdiction) and 10% of non-Indigenous hospitalised ARF/RHD cases (3-28%). The proportion of hospitalised RHD cases (36%) was half the proportion of hospitalised ARF cases (70%) notified to the ARF/RHD registers. The registers were found to capture few RHD cases in metropolitan areas (SA Metro: 13%, QLD Metro: 35%, WA Metro: 14%). Indigenous status, older age, comorbidities, drug/alcohol abuse and disease severity were predictors of cases appearing in the hospital data only (p < 0.05); sex was not a determinant. This analysis confirms that there are biases associated with the epidemiological analysis of single sources of case ascertainment for ARF/RHD using Australian data.

Development and Evaluation of a Prediction Model for Ascertaining Rheumatic Heart Disease Status in Administrative Data

Background

Previous research has raised substantial concerns regarding the validity of the International Statistical Classification of Diseases and Related Health Problems (ICD) codes (ICD-10 I05-I09) for rheumatic heart disease (RHD) due to likely misclassification of non-rheumatic valvular disease (non-rheumatic VHD) as RHD. There is currently no validated, quantitative approach for reliable case ascertainment of RHD in administrative hospital data.

Methods

A comprehensive dataset of validated Australian RHD cases was compiled and linked to inpatient hospital records with an RHD ICD code (2000-2018, n=7555). A prediction model was developed based on a generalized linear mixed model structure considering an extensive range of demographic and clinical variables. It was validated internally using randomly selected cross-validation samples and externally. Conditional optimal probability cutpoints were calculated, maximising discrimination separately for high-risk versus low-risk populations.

Results

The proposed model reduced the false-positive rate (FPR) from acute rheumatic fever (ARF) cases misclassified as RHD from 0.59 to 0.27; similarly for non-rheumatic VHD from 0.77 to 0.22. Overall, the model achieved strong discriminant capacity (AUC: 0.93) and maintained a similar robust performance during external validation (AUC: 0.88). It can also be used when only basic demographic and diagnosis data are available.

Conclusion

This paper is the first to show that not only misclassification of non-rheumatic VHD but also of ARF as RHD yields substantial FPRs. Both sources of bias can be successfully addressed with the proposed model which provides an effective solution for reliable RHD case ascertainment from hospital data for epidemiological disease monitoring and policy evaluation.

Voices behind the Statistics: A Systematic Literature Review of the Lived Experience of Rheumatic Heart Disease

In Australia, Aboriginal children almost entirely bear the burden of acute rheumatic fever (ARF) which often leads to rheumatic heart disease (RHD), a significant marker of inequity in Indigenous and non-Indigenous health experiences. Efforts to eradicate RHD have been unsuccessful partly due to lack of attention to voices, opinions and understandings of the people behind the statistics. This systematic review presents a critical, interpretive analysis of publications that include lived experiences of RHD. The review approach was strengths-based, informed by privileging Indigenous knowledges, perspectives and experiences, and drawing on Postcolonialism and Critical Race Theory. Fifteen publications were analysed. Nine themes were organised into three domains which interact synergistically: sociological, disease specific and health service factors. A secondary sociolinguistic analysis of quotes within the publications articulated the combined impact of these factors as ‘collective trauma’. Paucity of qualitative literature and a strong biomedical focus in the dominant narratives regarding RHD limited the findings from the reviewed publications. Noteworthy omissions included: experiences of children/adolescents; evidence of Indigenous priorities and perspectives for healthcare; discussions of power; recognition of the centrality of Indigenous knowledges and strengths; and lack of critical reflection on impacts of a dominant biomedical approach to healthcare. Privileging a biomedical approach alone is to continue colonising Indigenous healthcare.

A Validation Study: How Predictive Is a Diagnostic Coding Algorithm at Identifying Rheumatic Heart Disease in Western Australian Hospital Data?

BACKGROUND

International Classification of Diseases codes for rheumatic heart disease (RHD) (ICD-10 I05-I08) include valvular heart disease of unspecified origin, limiting their usefulness for estimating RHD burden. An expert opinion-based algorithm was developed to increase their accuracy for epidemiological case ascertainment. The algorithm included codes not defaulting to RHD ('probable') plus selected codes pertaining to mitral valve involvement in patients <60 years ('possible'). We aimed to determine the positive predictive value (PPV) for RHD of algorithm-selected hospital admissions.

METHODS

Chart reviews of RHD-coded admissions (n=368) to Western Australian tertiary hospitals (2009-2016) authenticated RHD diagnosis. We selected all cases with algorithm-positive codes from populations at high-risk of RHD and an age-stratified random sample from low-risk groups. RHD status was determined from echocardiographic reports or clinical diagnosis in charts. PPVs were compared by population risk status (high-risk/low-risk), age group, gender, principal/secondary diagnosis and probable/possible codes.

RESULTS

High-risk patients had higher PPVs than low-risk patients (83.8% vs 54.9%, p<0.0001). PPVs were 91.5% and 51.5% respectively for algorithm-defined 'probable RHD' and 'possible' codes (p<0.0001). The PPVs in low-risk patients were higher for principal diagnoses than secondary diagnoses (84.5% vs 44.8%, weighted p<0.0001) but were similar in high-risk patients (92.5% vs 81.7%, p=0.096).

CONCLUSION

The algorithm performs well for RHD coded as a principal diagnosis, 'probable' codes or in populations at high risk of RHD. Refinement is needed for identifying true RHD in low-risk groups.

Rheumatic heart disease in pregnancy: Profile of women admitted to a Western Australian tertiary obstetric hospital

This retrospective study assessed maternal and perinatal outcomes for women with rheumatic heart disease (RHD) admitted to the largest tertiary obstetric hospital in Western Australia from 2009 to 2016. Of 54 women identified, 75.9% were Indigenous, 59.3% lived in rural areas and 40.7% had severe RHD. Heart failure developed in 10% who gave birth. Indigenous women were younger, had higher gravidity (P = 0.0305), were more likely to receive secondary prophylaxis (P = 0.0041) and have sub-optimal antenatal clinic attendance (P = 0.0078). There were no maternal deaths and two perinatal deaths (4.0%), reflecting vigilance in the obstetric management of women with RHD in Western Australia.