Cardiovascular disease risk assessment for Aboriginal and Torres Strait Islander adults aged under 35 years: a consensus statement

Cardiovascular disease (CVD) is a leading cause of preventable morbidity and mortality in Aboriginal and Torres Strait Islander peoples. This statement from the Australian Chronic Disease Prevention Alliance, the Royal Australian College of General Practitioners, the National Aboriginal Community Controlled Health Organisation and the Editorial Committee for Remote Primary Health Care Manuals communicates the latest consensus advice of guideline developers, aligning recommendations on the age to commence Aboriginal and Torres Strait Islander CVD risk assessment across three guidelines.

C ardiovascular disease (CVD) is the largest contributor to preventable morbidity and mortality in Aboriginal and Torres Strait Islander peoples. 1 Although agestandardised CVD mortality has fallen by 40% over the past few decades, CVD still accounts for a quarter of Aboriginal and Torres Strait Islander deaths overall and 21% of all premature years of life lost. 1 CVD events and CVD-related mortality in the Aboriginal and Torres Strait Islander population occur, on average, about 10-20 years earlier than in non-Indigenous Australians. 2 Australian and international guidelines for best practice CVD prevention recommend using an absolute risk approach to CVD risk assessment. [3][4][5][6][7] The approach combines information from multiple risk factors to assess an individual's overall risk of having a CVD event at a given time. In Australia, absolute CVD risk is calculated using the National Vascular Disease Prevention Alliance (NVDPA) absolute risk algorithm, applied to individuals without a history of CVD. It first assesses for the following clinical conditions: • type 2 diabetes and age greater than 60 years; • type 2 diabetes and microalbuminuria (defined as albumin excretion rate > 20 μg/min or urinary albumin to creatinine ratio [ACR] > 2.5 mg/mmol for males and > 3.5 mg/mmol for females); • moderate to severe chronic kidney disease (CKD) (defined as persistently having a urine ACR > 25 mg/mmol for males or > 35 mg/mmol for females, or estimated glomerular filtration rate [eGFR] < 45 mL/min/1.73m 2 ) • systolic blood pressure of 180 mmHg or greater or diastolic blood pressure of 110 mmHg or greater; • previous diagnosis of familial hypercholesterolaemia; 8 or • serum total cholesterol greater than 7.5 mmol/L. Individuals with any of the above are automatically considered to be at high absolute risk of a future CVD event. People with an established diagnosis of CVD have the highest risk of a future event and should be managed according to the appropriate treatment guidelines.
For people without existing CVD or clinically determined high risk, the Framingham risk equation (FRE) is then used to calculate their risk of a primary CVD event in the next 5 years. 9 In Australia, risk is classified as low (< 10%), moderate (10-15%), high (> 15%), and clinically determined high risk. 6 This categorisation guides subsequent management in terms of provision of advice about protective and risk factors, commencement of blood pressure-and lipid-lowering therapy and review intervals. 6 This multiple risk factors approach is considered cost effective and minimises under-and overtreatment compared with single risk factor approaches. 10 Recent studies using representative national data demonstrate high levels of undertreatment according to absolute CVD risk across the entire Australian population. 11 • CVD risk factor screening should commence from the age of 18 years at the latest, including for blood glucose level or glycated haemoglobin, estimated glomerular filtration rate, serum lipids, urine albumin to creatinine ratio, and other risk factors such as blood pressure, history of familial hypercholesterolaemia, and smoking status.
• Individuals aged 18-29 years with the following clinical conditions are automatically conferred high CVD risk: • type 2 diabetes and microalbuminuria; • moderate to severe chronic kidney disease; • systolic blood pressure ≥ 180 mmHg or diastolic blood pressure ≥ 110 mmHg; • familial hypercholesterolaemia; or • serum total cholesterol > 7.5 mmol/L. • Assessment using the National Vascular Disease Prevention Alliance absolute CVD risk algorithm should commence from the age of 30 years at the latest -consider upward adjustment of calculated CVD risk score, accounting for local guideline use, risk factor and CVD epidemiology, and clinical discretion.
• Assessment should occur as part of an annual health check or opportunistically. Subsequent review should be conducted according to level of risk.
Changes in management as a result of this statement: From age 18 years (at the latest), Aboriginal and Torres Strait Islander adults should undergo CVD risk factor screening, and from age 30 years (at the latest), they should undergo absolute CVD risk assessment using the NVDPA risk algorithm.

Consensus statement
MJA 212 (9) ▪ 18 May 2020 423 and Torres Strait Islander population aged 35-74 years, 42.2% of people at high absolute CVD risk (without prior CVD) are using lipid-lowering therapy. 12 Inconsistency in clinical practice guidelines is one likely barrier to uptake of an absolute CVD risk approach. 13 There are three guidelines in common use that inform Aboriginal and Torres Strait Islander absolute CVD risk assessment and management: the NVDPA Guidelines for the management of absolute cardiovascular disease risk, 6  Although there is considerable alignment between the guidelines, including that all use the NVDPA absolute risk algorithm, there are key differences in some recommendations, particularly in relation to the age of commencement of absolute CVD risk assessment in Aboriginal and Torres Strait Islander peoples (Box 1).
In addition, there are differing recommendations for screening for individual CVD risk factors (Box 1). RPHCM recommends assessing multiple CVD risk factors from age 15-19 years as part of an adult health check. 14 The RACGP and NACCHO guidelines 15 recommend assessing multiple CVD risk factors from age 18-29 years. Aside from the different ages, recommendations differ from RPHCM through assessing for socioeconomic risk factors and family history of premature CVD and only assessing cholesterol and CKD among individuals aged 18-29 years with vascular risk factors (ie, family history of premature cardiovascular disease, CKD, overweight or obesity, smoking, diabetes, and/or elevated blood pressure 15 ). The NVDPA guidelines 6 contain no advice on screening for any of these risk factors in Aboriginal and Torres Strait Islander peoples below age 35 years.
When these guidelines were developed, there was little empirical evidence to guide recommendations specific to absolute CVD risk in Aboriginal and Torres Strait Islander peoples. 13 Evidence has since emerged to support lowering the age at which to commence CVD risk assessment in Aboriginal and Torres Strait Islander adults. 12 As guidelines are currently between updates, there is a demonstrable need for agreement on a consistent age to begin CVD risk assessment in the Aboriginal and Torres Strait Islander population.
This statement communicates the consensus advice of the organisations responsible for the current guidelines -the Australian Chronic Disease Prevention Alliance (incorporating NVDPA), the RACGP, NACCHO and the Editorial Committee for RPHCM -on the age to commence assessment of CVD risk for Aboriginal and Torres Strait Islander peoples. It outlines the methods used for the development of the consensus statement, the main changes to recommendations for CVD screening in individuals without prior CVD, and the evidence base informing the recommendations.

Methods
The consensus development process began with a formal review of evidence for the alignment of guidelines on Aboriginal and Torres Strait Islander absolute CVD risk, and included evidence on points of concordance and divergence between guidelines. 13 The review also included a systematic review of literature related to Aboriginal and Torres Strait Islander or Māori absolute CVD risk assessment or management published since 2012. • type 2 diabetes and microalbuminuria; • moderate to severe CKD; • systolic blood pressure of 180 mmHg or greater or diastolic blood pressure of 110 mmHg or greater; • previous diagnosis of familial hypercholesterolaemia; 8 or • serum total cholesterol greater than 7.5 mmol/L.
Individuals with a history of CVD should be managed according to relevant guidelines, 18-21 which include treatment with blood pressure-and lipid-lowering medication simultaneously (GRADE: 1A).

Management of CVD risk should include:
• commencement of treatment with blood pressure-and lipid-lowering medication simultaneously in individuals at high risk of CVD, unless contraindicated or clinically inappropriate (GRADE: 1A) -consider initiating treatment in people at moderate absolute CVD risk; 22,23 • commencement of blood pressure-lowering medication for patients with blood pressure persistently measuring more than 160/100 mmHg 24 (GRADE: 1A).
• advice and support for smoking cessation, regardless of the patient's level of CVD risk 15 (GRADE: 1A); • provision of sustained, frequent and specific advice about nutrition, physical activity and alcohol, with support and follow-up 6,15,16 (GRADE: 1B): • nutrition: recommend following the Dietary Approaches to Stop Hypertension (DASH) eating plan, a Mediterranean diet, or similar, according to latest evidence-based recommendations on dietary approaches to reducing CVD risk. [25][26][27] Consider referral to an accredited practising dietitian to assist in education and developing a tailored plan to address CVD risk through dietary changes; • physical activity: 2.5-5 hours of moderate intensity physical activity, or 1.2-2.5 hours of vigorous intensity physical activity, or an equivalent combination of moderate and vigorous activities, per week (any physical activity is better than none); 28 and Changes in assessment from current guidelines as a result of this consensus statement are presented in Box 1.

Evidence base for recommended changes
Emerging evidence shows that high absolute CVD risk starts earlier in Aboriginal and Torres Strait Islander peoples compared with non-Indigenous Australians. For individuals aged 35-44 years, hospitalisation and mortality rates for CVD in Aboriginal and Torres Strait Islander peoples were three times and eight times as high as that for non-Indigenous people respectively. 2 A 2018 study using nationally representative data from the 2012-13 Australian Aboriginal and Torres Strait Islander Health Survey found that 1.1% of Aboriginal and Torres Strait Islander peoples aged 18-24 years (95% CI, 0.0-2.5%) and 4.7% Aboriginal and Torres Strait Islander peoples aged 25-34 years (95% CI, 2.0-7.5%) were at high absolute risk of having a primary CVD event in the next 5 years. 12 These findings support those previously reported in specific Aboriginal and Torres Strait Islander populations. 30,31 The proportion of people aged 25-34 years at high risk (4.7%) 12 is similar to that seen in non-Indigenous people aged 45-54 years (4.0%), the age from which absolute CVD risk assessment is recommended for this population under the current NVDPA guidelines. 6 All Aboriginal and Torres Strait Islander peoples aged 18-34 years who were at high absolute risk of a primary CVD event were so classified based on the clinical criteria from the NVDPA algorithm. 12  While the existing evidence presents the case for lowering the age of commencing CVD risk assessment, it is currently not sufficient to ascertain exactly what age is most appropriate, and such decisions always need to be made with input from Aboriginal and Torres Strait Islander community members and leaders.
Optimising the approach to Aboriginal and Torres Strait Islander cardiovascular risk assessment

Social determinants of health
The greater an individual's socio-economic disadvantage, the worse their CVD health outcomes are likely to be. [33][34][35][36][37] Absolute CVD risk scores are likely to underestimate the true risk for socio-economically disadvantaged people. 38 This social gradient should be considered when approaching CVD risk assessment and management in Aboriginal and Torres Strait Islander peoples because of the ongoing socio-economic disadvantage caused by the continued legacy of colonisation in Australia. A fundamental cause of the persisting socio-economic and health disadvantages experienced by Aboriginal and Torres Strait Islander peoples is racism. 39 A high proportion of Aboriginal and Torres Strait Islander peoples report unfair treatment in the past 12 months based on race. 37

Social and emotional wellbeing
In the general population, a greater proportion of people with high compared with lower levels of psychological distress are at high primary risk of a CVD event, 40 and psychological distress may be a barrier to making changes that would reduce CVD risk. 41 Thirty per cent of Aboriginal and Torres Strait Islander adults report high or very high levels of psychological distress, at rates almost three times that of the non-Indigenous population. 42 In addition, for Aboriginal and Torres Strait Islander youth aged 10-24 years, suicide and self-inflicted injury is the leading contributor to burden of disease. 43 Therefore, it is especially important to consider social and emotional wellbeing alongside CVD risk assessment in Aboriginal and Torres Strait Islander peoples aged under 30 years and to consider the impact of psychological distress when approaching management.

Adapting to emerging evidence
Data to inform absolute CVD risk assessment and management are increasing rapidly, particularly in relation to Aboriginal and Torres Strait Islander peoples. 46 Moving towards a living guidelines approach -where guideline recommendations are updated frequently as new evidence becomes available, rather than intermittent updating of the guidelines in full -for CVD risk assessment and management guidelines would facilitate timely update of clinical guidelines, allowing for more rapid implementation of the best available evidence to improve patient outcomes. 46 This statement should be refined as new evidence emerges, including any unintended consequences that may emerge from these recommendations, such as overdiagnosis and treatment.

Conclusion
The past two decades have seen large improvements in CVD mortality for Aboriginal and Torres Strait Islander peoples. A consistent approach to CVD risk assessment and management from an early age, and with consideration of non-FRE risk factors, will support further improvements in Aboriginal and Torres Strait Islander health.