Summary of the ASPREE Clinical Trial

ASPREE (ASPirin in Reducing Events in the Elderly) is a large-scale, double-blind, randomised, placebo-controlled trial of low dose aspirin for primary prevention in healthy older people. The primary research question is:  does daily treatment of aspirin prolong healthy lifespan in people 70 years and older through the prevention of heart attack, stroke, cognitive decline, physical decline and cancers such as bowel cancer. 

ASPREE is an international multicentre trial which will be conducted in general practice in Australia and in clinical trial centres and primary care clinics in the United States. The study will recruit 19,000 healthy participants from various urban and rural locations throughout Australia and the United States. Participants will be randomised to take daily either 100mg enteric coated aspirin or placebo. Neither the participants nor the researchers will know who is taking which tablet. Follow-up is planned for an average of 5 years.

Why is it important?: The Australian and United States populations are ageing. As people age, they are more likely to develop disabilities related to vascular and other diseases. Heart attacks, stroke, cognitive decline, physical decline and cancers such as bowel cancer are al more common in older people. Treating these diseases is costly for the healthcare system and hence, it is of great public healht importance to determine what simple preventive measures can help keep older people living well for longer.

Aspirin may be one such preventive measure that will help extend healthy lifespan. Low-dose aspirin therpay has been shown to reduce the risk of strokes and heart attacks in a wide range of settings and there is increasing evidence to support its potential to delay dementia and prevent bowel cancer.

However part of the benefit of aspirin may be offset by a variety of adverse events related to bleeding including: cerebral and gastrointestinal haemorrhage, and anaemia. Such adverse effects may be increased in older persons.

Before healthcare professionals can know for sure if aspirin is prolongs healthy lifespan, the bendfits must be weighed against the risks. This requires a clinical trial of sufficent numbers to produce a result. 'Sufficient' numbers can be determined through a statistical process called 'powering'. The ASPREE trial has been powered to encompass enough participants so that the balance of risks and benefits of aspirin can be determined conclusively.

How will ASPREE participants be recruited?

In Australia, participants will be recruited through their General Practitioner (GP). This methodology is based ont eh highly successful Second Australian National Blood Pressure Study (ANBP2) and enables the participants the comfort of being medically managed by their own GP throughout the course of the trial. The ASPREE team will invite GPs to become co-investigators and those who accept will in turn invite eligible patients to consider becoming involved. Roughly 12,500 participants will be recruited in this way in Australia and an additional 6,500 will be recruited through clinical trial centres and primary care clinics in the United States of Australia.

Men and women are eligible to take part in this study if they are:

• aged 70 years or over
• able to attend visits at their usual GP

Unfortunately people cannot take part in this trial if they have:

• Blood vessel disease
• serious illness
• are taking aspirin, are allergic to it of cannot take it
• have had or are risk of serious bleeding
• are taking other'blood thinning' medication

What does the trial involve?

Study medication

Half of all participants will receive low dose aspirin (100mg) in an enteric coating. The other half will receive an identical tablet without aspirin (placebo). No-one will know who received which medication. Everyone is to take one tablet each day for five years.

Baseline measurements and tests

Before study medication is allocated, each participant will have a number of health, clinical and other measurements or assessments. These include blood pressure, blood cholestrol, phyical ability and memory and thinking tests. These measures will be spread over two visits with a research nurse. Any values outside the normal range will be reported to the GP.

Annual visits

The measures and assesments will be repeated annually. Any significant changes from baselines will be reported to the GP.

Will the trial be significant for medical practice?

ASPREE is likely to have a significant impact on medical care as the propotion of people over 70 years of age is increasing. Delaying the onset of chronic disease associated with ageing is therefore a high priority in medical practise. In additional, aspirin is cheap and affordable and therefore may be a very cost-effective measure if proven to prevent chronic disease. Also, ASPREE will provide GPs with evidence with which to make decisions regarding prescribing aspirin therapy for their older patients.

Funding: 

• The National Institure of Aging, part of the National Institutes of Health of the United States, has awarded the ASPREE trial $50 million (USD) from late 2009.
• NHMRC awarded $3.5 million Project Grant (awarded in 2005) to complete the ASPREE feasibility study and to act as leverage for further funding for the clinical trial
• Bayer Schering Pharma will provide study medication and placebo (~$2.5 million)
• Bayer Healthcareprovided an unencumbered educational set-up grant of $350k in 2006-7
• Victorian Cancer Agency provided $143k towards establishing ASPREE clinical trials activity in Shepparton, Vic.
• The National Heart Foundation of Australia provided $100k in 2003 towards towards the pilot study and another $100k towards establishing current recruitment.

How will ASPREE benefit the Australian population?:

ASPREE is a public good study. This means that the aim of the study is to improve the health of people in the general public and that the study is not being undertaken by a pharmaceutical company. The ASPREE study will also showcase to the world that Australia is on the cutting edge of preventive research. However, most importantly, the ASPREE study will answer the question about whether aspirin should be used to prolong healhty lifespan in older Australians.