Costs and healthcare use of patients with chronic kidney disease in the Northern Territory, Australia.

BACKGROUND: The burden of chronic kidney disease (CKD) is high in the Northern Territory (NT), Australia. This study aims to describe the healthcare use and associated costs of people at risk of CKD (e.g. acute kidney injury, diabetes, hypertension, and cardiovascular disease) or living with CKD in the NT, from a healthcare funder perspective. METHODS: We included a retrospective cohort of patients at risk of, or living with CKD, on 1 January 2017. Patients on kidney replacement therapy were excluded from the study. Data from the Territory Kidney Care database, encompassing patients from public hospitals and primary health care services across the NT was used to conduct costing. Annual healthcare costs, including hospital, primary health care, medication, and investigation costs were described over a one-year follow-up period. Factors associated with high total annual healthcare costs were identified with a cost prediction model. RESULTS: Among 37,398 patients included in this study, 23,419 had a risk factor for CKD while 13,979 had CKD (stages 1 to 5, not on kidney replacement therapy). The overall mean (± SD) age was 45 years (± 17), and a large proportion of the study cohort were First Nations people (68%). Common comorbidities in the overall cohort included diabetes (36%), hypertension (32%), and coronary artery disease (11%). Annual healthcare cost was lowest in those at risk of CKD (AUD$7,958 per person) and highest in those with CKD stage 5 (AUD$67,117 per person). Inpatient care contributed to the majority (76%) of all healthcare costs. Predictors of increased total annual healthcare cost included more advanced stages of CKD, and the presence of comorbidities. In CKD stage 5, the additional cost per person per year was + $53,634 (95%CI 32,769 to 89,482, p < 0.001) compared to people in the at risk group without CKD. CONCLUSION: The total healthcare costs in advanced stages of CKD is high, even when patients are not on dialysis. There remains a need for effective primary prevention and early intervention strategies targeting CKD and related chronic conditions.

Protocol and rationale of the Australian multicentre registry for serial cardiac computed tomography angiography (ARISTOCRAT): a prospective observational study of the natural history of pericoronary adipose tissue attenuation and radiomics.

Background: Vascular inflammation plays a crucial role in the development of atherosclerosis and atherosclerotic plaque rupture resulting in acute coronary syndrome (ACS). Pericoronary adipose tissue (PCAT) attenuation quantified from routine coronary computed tomography angiography (CCTA) has emerged as a promising non-invasive imaging biomarker of coronary inflammation. However, a detailed understanding of the natural history of PCAT attenuation is required before it can be used as a surrogate endpoint in trials of novel therapies targeting coronary inflammation. This article aims to explore the natural history of PCAT attenuation and its association with changes in plaque characteristics. Methods: The Australian natuRal hISTOry of periCoronary adipose tissue attenuation, RAdiomics and plaque by computed Tomographic angiography (ARISTOCRAT) registry is a multi-centre observational registry enrolling patients undergoing clinically indicated serial CCTA in 9 centres across Australia. CCTA scan parameters will be matched across serial scans. Quantitative analysis of plaque and PCAT will be performed using semiautomated software. Discussion: The primary endpoint is to explore temporal changes in patient-level and lesion-level PCAT attenuation by CCTA and their associations with changes in plaque characteristics. Secondary endpoints include evaluating: (I) impact of statin therapy on PCAT attenuation and plaque characteristics; and (II) changes in PCAT attenuation and plaque characteristics in specific subgroups according to sex and risk factors. ARISTOCRAT will further our understanding of the natural history of PCAT attenuation and its association with changes in plaque characteristics. Trial Registration: This study has been prospectively registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12621001018808).

Developing an integrated clinical decision support system for the early identification and management of kidney disease-building cross-sectoral partnerships.

BACKGROUND: The burden of chronic conditions is growing in Australia with people in remote areas experiencing high rates of disease, especially kidney disease. Health care in remote areas of the Northern Territory (NT) is complicated by a mobile population, high staff turnover, poor communication between health services and complex comorbid health conditions requiring multidisciplinary care. AIM: This paper aims to describe the collaborative process between research, government and non-government health services to develop an integrated clinical decision support system to improve patient care. METHODS: Building on established partnerships in the government and Aboriginal Community-Controlled Health Service (ACCHS) sectors, we developed a novel digital clinical decision support system for people at risk of developing kidney disease (due to hypertension, diabetes, cardiovascular disease) or with kidney disease. A cross-organisational and multidisciplinary Steering Committee has overseen the design, development and implementation stages. Further, the system's design and functionality were strongly informed by experts (Clinical Reference Group and Technical Working Group), health service providers, and end-user feedback through a formative evaluation. RESULTS: We established data sharing agreements with 11 ACCHS to link patient level data with 56 government primary health services and six hospitals. Electronic Health Record (EHR) data, based on agreed criteria, is automatically and securely transferred from 15 existing EHR platforms. Through clinician-determined algorithms, the system assists clinicians to diagnose, monitor and provide guideline-based care for individuals, as well as service-level risk stratification and alerts for clinically significant events. CONCLUSION: Disconnected health services and separate EHRs result in information gaps and a health and safety risk, particularly for patients who access multiple health services. However, barriers to clinical data sharing between health services still exist. In this first phase, we report how robust partnerships and effective governance processes can overcome these barriers to support clinical decision making and contribute to holistic care.

Barriers to and Facilitators of Implementing Guidelines for Detecting Familial Hypercholesterolaemia in Australia.

BACKGROUND: Familial hypercholesterolaemia (FH) is a genetic condition that is a preventable cause of premature cardiovascular morbidity and mortality. High-level evidence and clinical practice guidelines support preventative care for people with FH. However, it is estimated that less than 10% of people at risk of FH have been detected using any approach across Australian health settings. The aim of this study was to identify the implementation barriers to and facilitators of the detection of FH in Australia. METHODS: Four, 2-hour virtual focus groups were facilitated by implementation scientists and a clinicians as part of the 2021 Australasian FH Summit. Template analysis was used to identify themes. RESULTS: There were 28 workshop attendees across four groups (n=6-8 each), yielding 13 barriers and 10 facilitators across three themes: (1) patient related, (2) provider related, and (3) system related. A "lack of care pathways" and "upskilling clinicians in identifying and diagnosing FH" were the most interconnected barriers and facilitators for the detection of FH. CONCLUSIONS: The relationships between barriers and facilitators across the patient, provider, and system themes indicates that a comprehensive implementation strategy is needed to address these different levels. Future research is underway to develop a model for implementing the Australian FH guidelines into practice.

Pericoronary adipose tissue attenuation on coronary computed tomography angiography associates with male sex and Indigenous Australian status.

To evaluate if Indigenous Australians have higher coronary inflammation demonstrated non-invasively using pericoronary adipose tissue attenuation on coronary computed tomography angiography (CCTA). We retrospectively obtained a cohort 54 Indigenous patients age- and sex-matched to 54 non-Indigenous controls (age: 46.5 ± 13.1 years; male: n = 66) undergoing CCTA at the Royal Darwin Hospital and Monash Medical Centre. Patient groups were defined to investigate the interaction of ethnicity and sex: Indigenous + male, Indigenous + female, control + male, control + female. Semi-automated software was used to assess pericoronary adipose tissue attenuation (PCAT-a) and volume (PCAT-v). Males had significantly higher PCAT-a (- 86.7 ± 7.8 HU vs. - 91.3 ± 7.1 HU, p = 0.003) than females. Indigenous patients had significantly higher PCAT-v (1.5 ± 0.5cm3 vs. 1.3 ± 0.4cm3, p = 0.032), but only numerically higher PCAT-a (p = 0.133) than controls. There was a significant difference in PCAT-a and PCAT-v across groups defined by Indigenous status and sex (p = 0.010 and p = 0.030, respectively). Among patients with matching CCTA contrast density, multivariable linear regression analysis showed an independent association between Indigenous status and PCAT-a. Indigenous men have increased PCAT-a in an age- and sex-matched cohort. Male sex is strongly associated with increased PCAT-a. Coronary inflammation may contribute to adverse cardiovascular outcomes in Indigenous Australians, but larger studies are required to validate these findings.

Surgery for rheumatic heart disease in the Northern Territory, Australia, 1997-2016: what have we gained?

BACKGROUND: Between 1964 and 1996, the 10-year survival of patients having valve replacement surgery for rheumatic heart disease (RHD) in the Northern Territory, Australia, was 68%. As medical care has evolved since then, this study aimed to determine whether there has been a corresponding improvement in survival. METHODS: A retrospective study of Aboriginal patients with RHD in the Northern Territory, Australia, having their first valve surgery between 1997 and 2016. Survival was examined using Kaplan-Meier and Cox regression analysis. FINDINGS: The cohort included 281 adults and 61 children. The median (IQR) age at first surgery was 31 (18-42) years; 173/342 (51%) had a valve replacement, 113/342 (33%) had a valve repair and 56/342 (16%) had a commissurotomy. There were 93/342 (27%) deaths during a median (IQR) follow-up of 8 (4-12) years. The overall 10-year survival was 70% (95% CI: 64% to 76%). It was 62% (95% CI: 53% to 70%) in those having valve replacement. There were 204/281 (73%) adults with at least 1 preoperative comorbidity. Preoperative comorbidity was associated with earlier death, the risk of death increasing with each comorbidity (HR: 1.3 (95% CI: 1.2 to 1.5), p<0.001). Preoperative chronic kidney disease (HR 6.5 (95% CI: 3.0 to 14.0) p≤0.001)), coronary artery disease (HR 3.3 (95% CI: 1.3 to 8.4) p=0.012) and pulmonary artery systolic pressure>50 mm Hg before surgery (HR 1.9 (95% CI: 1.2 to 3.1) p=0.007) were independently associated with death. INTERPRETATION: Survival after valve replacement for RHD in this region of Australia has not improved. Although the patients were young, many had multiple comorbidities, which influenced long-term outcomes. The increasing prevalence of complex comorbidity in the region is a barrier to achieving optimal health outcomes.

Australian Atherosclerosis Society Position Statement on Lipoprotein(a): Clinical and Implementation Recommendations.

This position statement provides guidance to cardiologists and related specialists on the management of adult patients with elevated lipoprotein(a) [Lp(a)]. Elevated Lp(a) is an independent and causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valve disease (CAVD). While circulating Lp(a) levels are largely determined by ancestry, they are also influenced by ethnicity, hormones, renal function, and acute inflammatory events, such that measurement should be done after accounting for these factors. Further, circulating Lp(a) concentrations should be estimated using an apo(a)-isoform independent assay that employs appropriate calibrators and reports the results in molar units (nmol/L). Selective screening strategies of high-risk patients are recommended, but universal screening of the population is currently not advised. Testing for elevated Lp(a) is recommended in all patients with premature ASCVD and those considered to be at intermediate-to-high risk of ASCVD. Elevated Lp(a) should be employed to assess and stratify risk and to enable a decision on initiation or intensification of preventative treatments, such as cholesterol lowering therapy. In adult patients with elevated Lp(a) at intermediate-to-high risk of ASCVD, absolute risk should be reduced by addressing all modifiable behavioural, lifestyle, psychosocial and clinical risk factors, including maximising cholesterol-lowering with statin and ezetimibe and, where appropriate, PCSK9 inhibitors. Apheresis should be considered in patients with progressive ASCVD. New ribonucleic acid (RNA)-based therapies which directly lower Lp(a) are undergoing clinical trials.

Inpatient cardiac care for acute coronary syndromes in the Top End of Australia.

BACKGROUND: Disparities in cardiovascular outcomes between Aboriginal and Torres Strait Islander Australians and non-Indigenous Australians persist. This has previously been attributed to a combination of differences in burden of cardiovascular disease risk factors, and inpatient access to guideline-recommended care. AIMS: To assess differences in inpatient access to guideline-recommended acute coronary syndrome (GR-ACS) treatment between Aboriginal and Torres Strait Islander and non-indigenous patients admitted to Royal Darwin Hospital (RDH) with index ACS event. METHODS: This retrospective study included index ACS admissions (n = 288) to RDH between January 2016 and June 2017. Outcomes included rates of coronary angiography, percutaneous coronary intervention (PCI), surgical revascularisation, GR-ACS medications prescribed on discharge and short-term outcomes (30-day mortality and ACS readmissions; 12-month all cardiac-related readmissions). RESULTS: Two hundred and eighty-eight patients, including 109 (37.85%) Aboriginal and Torres Strait Islander patients, were included. Compared with non-indigenous patients, they were younger (median age 48 years vs 60 years; P < 0.01), with a greater burden of comorbidities, including diabetes (39% vs 19%; P < 0.01), smoking (68% vs 35%; P < 0.01) and chronic kidney disease (29% vs 5%; P < 0.01). There were no differences in rates of coronary angiography (98% vs 96%; P = 0.24) or PCI (47% vs 57%; P = 0.12), although there was a trend towards surgical revascularisation in Aboriginal and Torres Strait Islander patients (16% vs 8%; P = 0.047). There were no differences in 30-day mortality (1.8% vs 1.7%; P = 0.72), 12-month ACS readmissions (7% vs 4%; P = 0.20) or 12-month cardiac-related readmissions (7% vs 13%; P = 0.11). CONCLUSIONS: Aboriginal and Torres Strait Islander patients received similar inpatient ACS care and secondary prevention medication at discharge, with similar short-term mortality outcomes as non-indigenous patients. While encouraging, these outcomes may not persist long term. Further outcomes research is required, with differences compelling consideration of other primary and secondary prevention contributors.

Pulmonary hypertension in remote and disadvantaged population: overcoming unique challenges for improved outcomes.

Pulmonary hypertension (PH) is a common and debilitating medical condition with high mortality. PH research has traditionally focused on pulmonary arterial hypertension and its management in expert PH centres. Other forms of PH such as PH associated with cardiac or respiratory disease are more common, less well-understood and associated with higher mortality. Epidemiology of PH in disadvantaged, remote and rural regions, remains largely undocumented. In this review, we discuss the unique challenges in identifying PH in rural and disadvantaged populations using the Top End region of the Northern Territory of Australia as an example. We propose a simple diagnostic approach, ideally suited to regions where resource allocation is scarce, using clinical skills, echocardiography, and an escalation algorithm. The brief history, epidemiology and current literature on PH are summarised to inform the busy clinicians. We highlight two case examples from the Top End to illustrate the challenges and potential solutions.

Transcatheter mitral valve-in-valve: treatment of rheumatic heart disease in young patients.

BACKGROUND: Rheumatic heart disease (RHD) in young people presents a complex management problem. In Australia a significant proportion of those affected are Aboriginal and Torres Strait Islanders. Transcatheter mitral valve-in-valve (TMViV) replacement has emerged as an alternative to redo surgery in high-risk patients with degenerated mitral bioprostheses. The aim of this study is to review outcomes of TMViV replacement in young patients with RHD. METHODS: A single-centre, retrospective review of prospectively collected data on patients undergoing TMViV from December 2017 to June 2021. Primary outcome was major adverse cardiovascular events. Secondary outcome was post-operative trans-thoracic echocardiogram (TTE) results. RESULTS: There were seven patients with a mean age of 33 years and predominantly female (n = 5). Pre-operative comorbidities included diabetes (29%), chronic obstructive pulmonary disease (43%), left ventricular dysfunction (43%) and current smoking status (80%). Post-operative median length of hospital stay was 4 days with no post-operative renal failure, stroke, return to theatre, valve embolization or in hospital mortality. Post-operative TTE showed either nil or trivial central mitral regurgitation, no paravalvular leak and a median gradient of 5 mmHg (IQR 4.5, 7) across the new bioprosthesis; sustained at median follow-up of 22 months. CONCLUSION: Current literature of TMViV replacement is focused on an older population with concurrent comorbidities. This study provides a unique insight into TMViV replacement in a young cohort of patients with complex social and geographical factors which sometimes prohibits the use of a mechanical valve. The prevalence of RHD remains high for Aboriginal and Torres Strait Islanders, planning for future repeat valve operations should be considered from the outset. We consider TMViV as a part of a staged procedural journey for young patients with RHD.

Text Messages to Improve Medication Adherence and Secondary Prevention After Acute Coronary Syndrome: The TEXTMEDS Randomized Clinical Trial.

BACKGROUND: TEXTMEDS (Text Messages to Improve Medication Adherence and Secondary Prevention After Acute Coronary Syndrome) examined the effects of text message-delivered cardiac education and support on medication adherence after an acute coronary syndrome. METHODS: TEXTMEDS was a single-blind, multicenter, randomized controlled trial of patients after acute coronary syndrome. The control group received usual care (secondary prevention as determined by the treating clinician); the intervention group also received multiple motivational and supportive weekly text messages on medications and healthy lifestyle with the opportunity for 2-way communication (text or telephone). The primary end point of self-reported medication adherence was the percentage of patients who were adherent, defined as >80% adherence to each of up to 5 indicated cardioprotective medications, at both 6 and 12 months. RESULTS: A total of 1424 patients (mean age, 58 years [SD, 11]; 79% male) were randomized from 18 Australian public teaching hospitals. There was no significant difference in the primary end point of self-reported medication adherence between the intervention and control groups (relative risk, 0.93 [95% CI, 0.84-1.03]; P=0.15). There was no difference between intervention and control groups at 12 months in adherence to individual medications (aspirin, 96% vs 96%; ß-blocker, 84% vs 84%; angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, 77% vs 80%; statin, 95% vs 95%; second antiplatelet, 84% vs 84% [all P>0.05]), systolic blood pressure (130 vs 129 mm Hg; P=0.26), low-density lipoprotein cholesterol (2.0 vs 1.9 mmol/L; P=0.34), smoking (P=0.59), or exercising regularly (71% vs 68%; P=0.52). There were small differences in lifestyle risk factors in favor of intervention on body mass index <25 kg/m2 (21% vs 18%; P=0.01), eating ≥5 servings per day of vegetables (9% vs 5%; P=0.03), and eating ≥2 servings per day of fruit (44% vs 39%; P=0.01). CONCLUSIONS: A text message-based program had no effect on medical adherence but small effects on lifestyle risk factors. REGISTRATION: URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=364448; Unique identifier: ANZCTR ACTRN12613000793718.

Comparison of clinical manifestation among Australian Indigenous and non-indigenous patients presenting with pleural effusion.

BACKGROUND: There is sparse evidence in the literature in relation to the nature and causes of pleural effusion among Australian Indigenous population. AIM: To investigate the clinical and demographic characteristics of adult indigenous patients presenting with pleural effusion in the Northern Territory of Australia. METHODS: In this retrospective study, indigenous and non-indigenous adults diagnosed to have pleural effusion over a 2-year study period were included for comparative analysis. RESULTS: Of the 314 patients, 205 (65%) were non-indigenous and 52% were male. In comparison with non-indigenous patients, the indigenous patients were younger (50 years (interquartile range (IQR) 39-60) vs 63 years (IQR 52-72); P < 0.001), female (61% vs 41%; P = 0.001), had a higher prevalence of renal and cardiovascular disease and tended to have exudative effusion (93% vs 76%; P = 0.032). Infections were judged to be the most common cause of effusion in both groups, more so among the indigenous cohort. Effusion secondary to renal disease was higher (13% vs 1%; P < 0.001) among Australian Indigenous patients, but in contrast, malignant effusions were higher (13% vs 4%; P = 0.004) among non-indigenous patients. Length of hospital stay was longer for indigenous patients (P = 0.001), and a greater proportion received renal dialysis (13% vs 1%; P < 0.001). Intensive care unit admission rates were higher with infective aetiology of pleural effusion (82% vs 53% indigenous and 44% vs 39% non-indigenous respectively). Re-presentations to hospital were higher among indigenous patients (46% vs 33%; P = 0.046) and were associated with renal and cardiac disease and malignancy in non-indigenous patients. CONCLUSION: There are significant differences in the way pleural effusion manifests among Australian Indigenous patients. Understanding these differences might facilitate approaches to management and to implementation of strategies to reduce morbidity and mortality in this population.

Prosthetic valve endocarditis presenting as meningoencephalitis complicated by pseudo-aneurysms in a remote Aboriginal healthcare setting in Australia: a case report.

BACKGROUND: The Australian Aboriginal population has a high burden of cardiac conditions predisposing patients to infective endocarditis. Pseudo-aneurysms are a rare and potentially fatal complication of both prior valvular surgery and endocarditis. CASE SUMMARY: A 31-year-old female with a history of bicuspid aortic valve requiring valve replacement presented with meningoencephalitis. Transoesophageal echo and positive blood cultures for Staphylococcus aureus confirmed prosthetic valve endocarditis (PVE). Aortic root mycotic pseudo-aneurysms developed during antimicrobial therapy and two large pseudo-aneurysms remain post-redo valve, root and arch replacement. DISCUSSION: Complications associated with PVE are common, especially due to S. aureus. Redo cardiac surgery is high risk, percutaneous treatments may be technically difficult due to altered post-operative anatomy, and medication adherence issues and lack of healthcare engagement further compromise optimal care in this patient population.

Left atrial, pulmonary vein, and left atrial appendage anatomy in Indigenous individuals: Implications for atrial fibrillation.

BACKGROUND: Indigenous Australians experience a greater burden of AF. Whether this is in-part due to differences in arrhythmogenic structures that appear to contribute to AF differences amongst other ethnicities is not known. METHODS: We studied forty individuals matched for ethnicity and other AF risk factors. Computed tomography imaging was used to characterise left atrial (LA), pulmonary vein (PV), and left atrial appendage (LAA) anatomy. RESULTS: There were no significant differences in LA diameters or volumes between Indigenous and non-Indigenous Australians. Similarly, we could not detect any consistent differences in PV number, morphology, diameters, or ostial characteristics according to ethnicity. LAA analyses suggested that Indigenous Australians may have a greater proportion of non chickenwing LAA type, and a tendency for eccentric, oval-shaped LAA ostia; however, there were no other differences seen with regards to LAA volume or depth. Indexed values for LA, PV and LAA anatomy corrected for body size were broadly similar. CONCLUSIONS: In a cohort of individuals matched for AF risk factors, we could find no strong evidence of ethnic differences in LA, PV, and LAA characteristics that may explain a predisposition of Indigenous Australians for atrial arrhythmogenesis. These findings, in conjunction with our previous data showing highly prevalent cardiometabolic risk factors in Indigenous Australians with AF, suggest that it is these conditions that are more likely responsible for the AF substrate in these individuals. Continued efforts should therefore be directed towards risk factor management in an attempt to prevent and minimise the effects of AF in Indigenous Australians.

Surgical and percutaneous management of Aboriginal Australians with rheumatic heart disease: Timeliness and concordance between practice and guidelines.

BACKGROUND: Rheumatic heart disease (RHD) affects over 40 million people globally who are predominantly young and from impoverished communities. The barriers to valvular intervention are complex and contribute to the high morbidity and mortality associated with RHD. The rates of guideline indicated intervention in patients with significant RHD have not yet been reported. METHODS: From 2007 to 2017, we used the Australian Northern Territory Cardiac Database to identify patients with RHD who fulfilled at least one ESC/EACTS guideline indication for mitral valve intervention. Baseline clinical status, comorbidities, echocardiographic parameters, indication for intervention, referral and any interventions were recorded. RESULTS: 154 patients (mean age 38.5 ± 14.6, 66.1% female) were identified as having a class I or IIa indication for invasive management. Symptoms, atrial fibrillation and pulmonary hypertension were the most common indications for surgery (74.5%, 48.1%, 40.9%). From the onset of a guideline indication the actuarial rates of accepted referral and intervention within two-years were 66.0% ± 4.0% and 53.1% ± 4.4% respectively. Of those who were referred and accepted for intervention, 86% received it within 2 years. The rates of accepted referral for patients with class I indications were 72.5% ± 4.2% while class IIa indications were 42.5% ± 9.0% (p<0.001). CONCLUSIONS: Approximately half of Aboriginal patients with significant rheumatic mitral valve disease who met ESC/EACTS guideline indications for intervention received surgery or valvuloplasty within two-years. A significant difference in referral rates was found between Class I and Class IIa indications for valvular intervention.

Atrial Fibrillation in Remote Indigenous and Non-Indigenous Individuals Hospitalised in Central Australia.

BACKGROUND: The epidemiology of atrial fibrillation (AF) amongst Indigenous populations remains poorly characterised. We studied hospitalisations for AF in Central Australia, the most populous Indigenous region in the country. METHODS: Patients with a diagnosis of AF admitted to Alice Springs Hospital, the only secondary health care facility and provider of cardiac care in remote Central Australia, were identified from 2006 to 2016. Age and gender-specific hospitalised AF prevalence, comorbidities, and CHA2DS2-VASc scores were ascertained. RESULTS: Of 57,056 admitted patients over the study period, 1,210 (2.1%; 46% Indigenous) had a diagnosis of AF. For Indigenous and non-Indigenous individuals <45 years, hospitalised AF prevalence per 10,000 population was 105 (CI 84-131) and 50 (CI 36-68) in males (ratio=2.10), and 98 (CI 77-123) and 12 (CI 6-23) in females (ratio=7.92), respectively. For Indigenous and non-Indigenous individuals ≥65 years, hospitalised AF prevalence per 10,000 was 1,577 (CI 1,194-2,026) and 2,326 (CI 2,047-2,623) in males (ratio=0.68), and 1,713 (CI 1,395-2,069) and 1,897 (1,623-2,195) in females (ratio=0.90). Indigenous individuals had higher rates of cardiometabolic comorbidities, particularly at younger ages. CHA2DS2-VASc scores were greater in Indigenous individuals, particularly those <45 years (2.5±1.5 versus 0.7±1.1, p<0.001). CONCLUSIONS: The prevalence of hospitalised AF amongst Indigenous people in remote Central Australia was significantly higher than in non-Indigenous individuals, particularly in younger age groups and females. Indigenous individuals with hospitalised AF also had a markedly greater prevalence of cardiometabolic comorbidities and elevated stroke risk. These data suggest that AF may be contributing to the gap in morbidity and mortality experienced by Indigenous Australians.

Obstructive Sleep Apnoea and Cardiac Disease Among Aboriginal Patients in the Northern Territory of Australia.

BACKGROUND: There is paucity of information on obstructive sleep apnoea (OSA) and cardiac diseases among Aboriginal Australian patients. This study evaluates the association of various cardiac disease profiles among Aboriginal patients undergoing a diagnostic polysomnography (PSG). METHOD: In this 5-year retrospective study demographics, clinical characteristics, medical and cardiac -conditions were analysed. RESULTS: There were total of 340 eligible patients included in the study. The median age was 47 (38-57) years, 51% were males and obesity was noted in 78%. In the overall study participants, cardiac diseases were present in 46%: coronary artery disease (CAD) in 27%, pulmonary hypertension (PH) 19% and atrial fibrillation (AF) 14%. Diabetes and hypertension were noted in 42 and 41% of patients. Overall, 73/340 (21.5%) had two, 69/340 (20.3%) three, 55/340 (16.2%) four, 40/340 (11.8%) five and 10/340 (2.9%) had six comorbidities. In the overall study participants, 297/340 (87%) had OSA (Apnoea-Hypopnoea Index [AHI]>5/hour). Co-occurrence of OSA and cardiac diseases was found in 140/297 (47%), CAD being the commonest (27%). Patients with OSA had a higher number of comorbidities compared to patients without sleep apnoea. Hospital admissions frequency showed a median 2 (IQR: 0-4) times readmission rates since the diagnosis of OSA overall compliance with CPAP therapy was observed in 63 (43%). CONCLUSION: Our study demonstrated that a significant proportion of Aboriginal patients with OSA have co-existing cardiac diseases, with CAD being the commonest. Patients with OSA had a higher number of comorbidities compared to patients without sleep apnoea. Furthermore, hospital admission frequency increased among OSA patients with multiple comorbidities.

Top End Pulmonary Hypertension Study: Understanding Epidemiology, Therapeutic Gaps and Prognosis in Remote Australian Setting.

INTRODUCTION: The Top End of Australia has a high proportion of Indigenous people with a high burden of chronic cardiac and pulmonary diseases likely to contribute to pulmonary hypertension (PH). The epidemiology of PH has not been previously studied in this region. METHODS: Patients with PH were identified from the Northern Territory echocardiography database from January 2010 to December 2015 and followed to the end of 2019 or death. Pulmonary hypertension was defined as a tricuspid regurgitation velocity ≥2.75 m/s measured by Doppler echocardiography. The aetiology of PH, as categorised by published guidelines, was determined by reviewing electronic health records. RESULTS: 1,764 patients were identified comprising 49% males and 45% Indigenous people. The prevalence of PH was 955 per 100,000 population (with corresponding prevalence of 1,587 for Indigenous people). Hypertension, atrial fibrillation, diabetes and respiratory disease were present in 85%, 45%, 41% and 39%, respectively. Left heart disease was the leading cause for PH (58%), the majority suffering from valvular disease (predominantly rheumatic). Pulmonary arterial hypertension (PAH), respiratory disease related PH, chronic thromboembolic PH (CTEPH) and unclear multifactorial PH represented 4%, 16%, 2% and 3%, respectively. Underlying causes were not identifiable in 17% of the patients. Only 31% of potentially eligible patients were on PAH-specific therapy. At census, there was 40% mortality, with major predictors being age, estimated pulmonary artery systolic pressure (ePASP) and Indigenous ethnicity. CONCLUSION: Pulmonary hypertension is prevalent in Northern Australia, with a high frequency of modifiable risk factors and other treatable conditions. Whether earlier diagnosis, interpretation and intervention improve outcomes merits further assessment.

Prognostic value of coronary artery calcium scoring and computed tomography coronary angiography in remote Indigenous and non-Indigenous Australians.

BACKGROUND: The long-term prognostic utility of coronary calcification and coronary artery disease on computed tomography coronary angiography (CTCA) in remote Indigenous and non-Indigenous Australians is not known. METHODS: Consecutive patients undergoing CTCA from 2013 to 2017 in Central Australia were followed-up for major adverse cardiovascular events (MACE). RESULTS: 347 patients were included (50 ± 12 years; 47% female; 39% Indigenous). 172 (50.0%) exhibited coronary calcification. CTCA demonstrated no coronary artery disease (CAD) in 137 (39.5%), non-obstructive CAD in 149 (42.9%), and obstructive CAD in 61 (17.6%) patients. Although Indigenous ethnicity was associated with coronary calcification and baseline CAD in age- and gender-adjusted models, this association was non-significant after accounting for comorbidities. Over 4.6 years (IQR 3.52-5.68) of follow-up, MACE incidence rates per 100 person-years were 2.92 (CI 1.92-4.44) and 0.48 (CI 0.18-1.27) in those with and without calcification respectively (p = 0.001), and 0.15 (CI 0.02-1.09), 1.32 (CI 0.69-2.54), and 6.23 (CI 3.81-10.16) in patients with no, non-obstructive, and obstructive CAD respectively (p < 0.001). Coronary calcification and obstructive CAD were associated with 5-fold (HR 5.25, 95% CI 1.66-16.59, p = 0.005) and 6-fold (HR 6.35, 95% CI 2.70-14.89, p < 0.001) greater hazards of MACE respectively in multivariable models, with no significant interaction by ethnicity in these associations seen. CONCLUSIONS: The prognostic value of coronary calcification and CAD on CTCA amongst remote Indigenous individuals appears similar to that seen in non-Indigenous populations. Our data suggest that coronary artery calcium scoring and CTCA can be used to risk-stratify in remote settings where a normal study is associated with an excellent prognosis for at least two years.