Aspirin, a potent anti-platelet agent, is frequently used as prophylactic treatment to preclude thrombus formation. However, due to its anti-coagulative effects, it has been shown to cause bleeding in the gastrointestinal tract, especially for elderly patients. This is particularly dangerous because if any form of trauma or injury is sustained, the resulting bleeding may be life-threatening.

Increased bleeding risk in over-75s

Recently, research conducted by Professor Peter Rothwell, from Oxford University, studied individuals who had previously had a myocardial infarction or stroke and were currently being prescribed aspirin.

Whilst aspirin increases the risk of internal bleeding in all individuals, this effect is particularly pronounced in individuals aged over 75 years – with their risk being increased up to 10 times that of other age groups. This has important consequences for the routine prescription of aspirin in elderly patients, especially due to their predisposition to falls because of fragile bones or diminished vision.

Approximately 3,166 individuals who had previously suffered from a myocardial infarction or stroke were included in the trial and were monitored for a 10-year period. The outcome selected was hospitalisation rate for bleeding, which was approximately 1.5% for individuals aged under 65 and 3.5% for individuals in the age range of 75 to 84.

This represents a considerable increase in risk with age. It was also noted that the severity of bleeding also varied with age; the probability of life-threatening internal bleeding increased with an increase in age.

When prescription of aspirin is beneficial

As aspirin contributes to approximately greater than “3,000 deaths” annually, it is responsible for a considerable amount of mortality which can be avoided by changing prescription. Due to increased predisposition to cardiovascular events such as strokes with increasing age, elderly individuals are often prescribed anti-platelet agents to prevent excessive clotting.

It is estimated that between 40 to 60% of individuals aged over 75 years old consume aspirin as a preventative measure.

The usage of aspirin is primarily recommended if an individual has had a previous major cardiovascular event. This is because the benefits of preventing recurrence of events in these individuals are relatively more significant compared to the risks of extracranial or cerebral haemorrhage.

Aspirin usage is only recommended for individuals who fall above a certain threshold for cardiovascular risk. For purposes of primary prevention, other pharmaceutical drugs such as statins are preferred due to their ability to lower cholesterol, a potent cardiovascular risk factor.

Concurrent usage of proton pump inhibitors

A solution has been proposed to diminish the probability of upper gastrointestinal tract bleeding – individuals are recommended to simultaneously use proton pump inhibitors (PPIs) along with aspirin to reduce acid reflux and therefore harmful changes to gastric and oesophageal mucosa.

However, although upper gastrointestinal tract bleeding is less disabling in younger age groups, it is a serious life-threatening emergency in the geriatric population. Therefore, physicians may need to start prescribing PPIs in parallel to reduce the risk of fatal bleeding.

Dr. Tim Chico, a consultant cardiologist has commented on the widespread use of aspirin stating that, “Although bleeding is a well-recognised side effect of aspirin, this drug is still seen by many people as harmless, perhaps because of how easily it can be bought over the counter.”

This statement succinctly encapsulates why aspirin is used so commonly and highlights the need for additional barriers to be implemented. For instance, aspirin should only be retailed to customers if they have specific referrals for the drug from a registered healthcare professional.

Although the potentially adverse effects of aspirin are well-established and validated by the results of this research study, important limitations of the study exist.

These include the fact that it merged participants who had suffered from both strokes and myocardial infarctions – follow-up treatment for both of these events differs; and therefore, patients with a myocardial infarction are more likely to present with bleeding due to “dual antiplatelet therapy”.

Despite these shortcomings, the research study presents important findings which will influence the clinical usage of aspirin for prevention purposes in the future. MIMS

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