The IDEAL study is a randomized controlled trial among people referred to pathology services to have blood cholesterol measured. Study participants will have cardiovascular risk factors (e.g. age, sex, blood pressure, diabetes, smoking status) measured within an assessment station at pathology services. A report on cardiovascular risk, in addition to blood cholesterol results, will be sent to the referring doctor along with recommended treatment strategies among those participants randomized to intervention. For control participants, the usual care process will be provided in which only blood cholesterol results will be sent to the referring doctor. The new intervention is expected to lead to better identification and treatment of people at high risk for cardiovascular disease events.

The IDEAL study aims to improve the way doctors identify and manage patients at risk of cardiovascular disease, including conditions such as heart attack or stroke. This research focuses on an improved service to work out a patient's risk of heart attack or stroke and deliver this information to doctors to help them make well-informed treatment decisions to prevent cardiovascular disease and improve outcomes for their patients.

This IDEAL study is a randomized clinical trial of the IDEAL service to be conducted among 9,714 participants attending pathology services in Tasmania, Australia.

Patients attending pathology service clinics around Tasmania for a cholesterol test may be invited to participate. Participants will have their risk of cardiovascular disease assessed in a purpose-built assessment station where information about their cardiovascular disease risk factors, such as smoking, will be collected and blood pressure measured. An estimate of the chances of that patient having a heart attack or stroke in the next 5 years will be calculated and sent to their referring doctor along with their pathology results on the requested blood test report.

Based on the patient's risk of cardiovascular disease, appropriate advice according to recommended treatment guidelines will be provided on the pathology report as an aid for doctors to make better-informed decisions to manage patients at risk of cardiovascular disease.

Participants will also be asked to complete a questionnaire to explore issues of cardiovascular disease risk in more depth, with follow-up questionnaires at 6 and 12 months. After 12 months researchers will examine if there is an improvement in cardiovascular disease risk management and health outcomes for participants whose doctors received the cardiovascular disease risk information on the pathology report. This will be done through data linkage with national and state level data, as well as through asking participants to re-complete the questionnaire.

In addition, a qualitative research program will be conducted to understand the barriers and enablers to uptake of the IDEAL service from the perspective of pathology staff, doctors and patients.

Inclusion Criteria:

• Patients referred to pathology services for blood cholesterol (lipids; total cholesterol and HDL cholesterol) who are eligible for absolute CVD risk assessment according to the National Vascular Disease Prevention Alliance guidelines (this includes all adults aged 45 years and over without a known history of CVD, or Aboriginal and Torres Strait Islander people aged 35 years or over) and willing to provide permission to access to PBS-linked data on medications prescribed and dispensed.
• Adults already deemed to be at increased risk that do not require absolute CVD risk assessment according to guidelines will also be included because there is evidence that these people are undertreated (Heeley EL, et al Med J Aust 2010;192:254-9; Peiris DP, et al Med J Aust 2009;191:304-9) and therefore may benefit from improved assessment. This includes adults with any of the following: Diabetes and age >60 years; Diabetes with microalbuminuria (>20 mcg/min or urinary albumin:creatinine ratio >2.5 mg/mmol for males, >3.5 mg/mmol for females); Moderate or severe CKD (persistent proteinuria or estimated glomerular filtration rate (eGFR) <45 mL/min/1.73 m2); A previous diagnosis of familial hypercholesterolaemia; Serum total cholesterol >7.5 mmol/L; Aboriginal and Torres Strait Islander adults aged over 74

Exclusion Criteria:

• Adults already taking antihypertensive or lipid lowering medications (determined by self-report at baseline)
• if the referring doctor is not from a general practice included in the study cluster list,
• if participants cannot provide an email address to be used to provide a copy of their signed consent form.
• If at least one measurement of blood pressure is unable to be obtained at baseline assessment.
• For safety reasons, people will be excluded if they are found at the time of assessment at the pathology services with an average systolic blood pressure =180 mmHg or diastolic blood pressure =110 mmHg.

The deidentified study data, including data dictionaries, will be made publicly available on reasonable request via the University of Tasmania's Research Data Portal (consistent with the Australian Code for the Responsible Conduct of Research).

12 months after publication of the principal findings

Access subject to approvals by the Principal Investigator consistent with the Australian Code for the Responsible Conduct of Research.

Allocation is concealed from all people involved in eligibility screening and recruitment.

Pathology services reception and blood collection staff members may be employed across different collection centers that could include both intervention and control sites. Thus, concealment at the cluster level (as per this study design) is critical and all procedures undertaken by staff members interacting with participants (reception and blood collection staff) will be identical. At the participant level, there will be no indication provided regarding allocation (all participants will have the same information and undergo the same protocol at baseline assessment). Investigators will be blinded to participant allocation. Outcomes assessment is via linkage to health outcomes data.