Elsevier

American Heart Journal

Volume 203, September 2018, Pages 4-11
American Heart Journal

Trial Design
The AUStralian MEDiterranean Diet Heart Trial (AUSMED Heart Trial): A randomized clinical trial in secondary prevention of coronary heart disease in a multiethnic Australian population: Study protocol

https://doi.org/10.1016/j.ahj.2018.05.010Get rights and content

Abstract

The Mediterranean diet was first characterized as a heart-protective diet in the 1960s. The significant cardioprotective effects of the Mediterranean diet in comparison to the standard-care low-fat diet have been established in the primary prevention of cardiovascular disease (CVD); however, there is insufficient evidence in secondary prevention research to influence the current standard of care. Opportunity exists to assess the Mediterranean diet as a therapeutic target for secondary CVD prevention within Australia's ethnoculturally diverse communities.

The AUSMED Heart Trial is a multisite randomized controlled trial that will evaluate the efficacy of the Mediterranean diet for secondary prevention of CVD in the Australian health care setting. This trial aims to evaluate the effect of a 6-month Mediterranean diet intervention (delivered by dietitians) versus a “standard-care” low-fat diet in reducing the composite incidence of cardiovascular events at 12 months and at trial end in participants with documented evidence of a previous acute myocardial infarction at trial entry. The quality of the diet at baseline and follow-up will be assessed using comprehensive dietary questionnaires and diaries as well as relevant dietary biomarkers (such as urinary polyphenols and erythrocyte fatty acids).

Cardiovascular risk markers, including novel measures of immune and inflammatory status, endothelial function, vascular compliance, platelet activity, and body composition, will be collected to explore possible mechanisms for treatment effect. Cost-effectiveness will also be estimated to support policy translation.

We plan to recruit 1,032 participants (516 per arm) from cardiology clinics in major Australian hospitals in Melbourne, Adelaide, and Brisbane.

Section snippets

Background

Cardiovascular disease (CVD) is a major cause of disease burden and death in the Australian population1 and represents a global health care crisis. Modifiable risk factors account for more than 90% of the population-attributable risk for acute myocardial ischemia worldwide,2 and with the exception of smoking, most of these factors are directly related to food habits. Despite recent efforts to target diet in primary prevention of CVD, these have not been paralleled in secondary or tertiary

Design

The AUSMED Heart Trial (Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12616000156482) is a 6-month randomized, controlled, single-blind dietary intervention in a high-risk patient group who have experienced an AMI. The primary end point will be the difference in secondary cardiovascular event rates at 1 year, between the Mediterranean diet and low-fat diet participants. By following up participants until 12 months, 6 months after the dietary intervention and staple

Dietary intake

Dietary intake will be measured for each participant using 7-day food diaries and a pilot-validated Cardio-Med Questionnaire including a 115-item food frequency questionnaire (FFQ) purpose built by the investigators to capture adherence to the principles of a Mediterranean diet in a multiethnic cohort (Kucianski et al., unpublished). Data from food diaries and FFQs will be validated by the APD and analyzed using a standard nutrient analysis program (FoodWorks™ ver 8.0; Xyris Software, Brisbane,

Discussion

The Mediterranean diet was first described as cardioprotective in the 1960s, yet dietary prevention and management strategies have largely focused on reduction of saturated fat and dietary cholesterol for the past 50 years, including in Australia.33 This focus on dietary fat may have inadvertently increased intakes of highly processed carbohydrates, contributing further to the obesity and diabetes epidemics worldwide, which in turn lead to increased CVD morbidity and mortality. There is now a

Acknowledgments

We thank La Trobe University (Understanding Disease RFA Start-Up Grant, 2014; La Trobe University DVCR support grant, 2018) and the ongoing support of our industry partners (Boundary Bend P/L [Cobram Estate EVOO], the Almond Board of Australia, Jalna Dairy Foods, Simplot Australia, Carman's, and Heinz) for supply of key foods to be provided to participants of this trial. The authors also wish to thank several contributing staff: Dr Wolf Marx (protocol updates and revisions to ethics), PhD

Author contributions

Itsiopoulos C. is the chief investigator of the study and has primary responsibility for the final content. Itsiopoulos C., Thomas C.J., Mayr H.L., and Kucianski T. wrote the article. All authors had a significant input into the design of the protocol. All authors read and approved the final manuscript. The authors declare that there is no conflict of interest.

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