July 20, 2011 (Madrid, Spain) — A new study has confirmed the importance of continuing to take aspirin long term for patients with a history of heart disease [1].
The study, published online in the British Medical Journal on July 19, 2011, found that patients who stop taking aspirin are at a significantly increased risk of MI than those who continue treatment.
Researchers, led by Dr Luis Garcia Rodriguez (Spanish Centre for Pharmacoepidemiologic Research, Madrid, Spain), explain that low-dose aspirin is a standard treatment for the secondary prevention of cardiovascular outcomes. However, despite strong evidence supporting the protective effects of low-dose aspirin, around half of patients discontinue treatment. While many studies have shown this to be associated with an increased risk of cardiovascular events, they have all taken place in secondary care centers.
To study this issue in a primary care population, Garcia Rodriguez and colleagues analyzed data of 39 513 patients from the Health Improvement Network, a large UK database of primary care records. Patients were aged 50 to 84 years, with a first low-dose aspirin prescription for the prevention of cardiovascular outcomes from 2000 to 2007, and were followed for three years.
The authors conducted a nested case-control analysis and compared 1222 cases (patients who had an MI or coronary heart disease [CHD] death) with 5000 controls. Aspirin had been discontinued in 12.2% of cases and 11.0% of controls. Compared with current use, recent discontinuation was associated with a clinically and statistically significant increase in risk of nonfatal MI and in the combined outcome of death from CHD and nonfatal MI. There was no significant difference in risk of CHD death alone.
Risk of Major Cardiovascular Events in Those Who Discontinued vs Those Who Continued Aspirin
The results translate into four additional MIs each year for every 1000 patients who discontinued aspirin. The increased risk was present irrespective of the length of time the patient had previously been taking low-dose aspirin.
The authors note that these results support those of previous studies in secondary care and show that they are applicable to the general population. "Reducing the number of patients who discontinue low-dose aspirin could have a major impact on the benefit obtained with low-dose aspirin in the general population," they add. They call for further research to test whether efforts to encourage patients to continue prophylactic treatment with low-dose aspirin will decrease MI rates.
q"Any day off aspirin is a day at risk for patients with previous cardiovascular disease."
In an accompanying editorial [2], Dr Giuseppe Biondi-Zoccai (University of Modena, Italy) and Dr Giovanni Landoni (Università Vita-Salute San Raffaele, Milan, Italy) write: "any day off aspirin is a day at risk for patients with previous cardiovascular disease."
But the editorialists note that some patients may not be able to take aspirin because of bleeding risk, and that the risk-benefit ratio of aspirin in individual patients should always be considered. But in general, "patients on chronic low-dose aspirin for secondary prevention of cardiovascular disease should be advised that unless severe bleeding ensues or an informed colleague explicitly says so, aspirin should never be discontinued given its overwhelming benefits on atherothrombosis, as well as colorectal cancer and venous thromboembolism."
They add: "Accordingly, doctors should maintain their patients on low-dose aspirin as long as they can and carefully assess individual patients for the risk of both thrombosis and bleeding before discontinuing aspirin for invasive procedures. Patients who need to discontinue aspirin should do so for the minimum time necessary."
The study, published online in the British Medical Journal on July 19, 2011, found that patients who stop taking aspirin are at a significantly increased risk of MI than those who continue treatment.
Researchers, led by Dr Luis Garcia Rodriguez (Spanish Centre for Pharmacoepidemiologic Research, Madrid, Spain), explain that low-dose aspirin is a standard treatment for the secondary prevention of cardiovascular outcomes. However, despite strong evidence supporting the protective effects of low-dose aspirin, around half of patients discontinue treatment. While many studies have shown this to be associated with an increased risk of cardiovascular events, they have all taken place in secondary care centers.
To study this issue in a primary care population, Garcia Rodriguez and colleagues analyzed data of 39 513 patients from the Health Improvement Network, a large UK database of primary care records. Patients were aged 50 to 84 years, with a first low-dose aspirin prescription for the prevention of cardiovascular outcomes from 2000 to 2007, and were followed for three years.
The authors conducted a nested case-control analysis and compared 1222 cases (patients who had an MI or coronary heart disease [CHD] death) with 5000 controls. Aspirin had been discontinued in 12.2% of cases and 11.0% of controls. Compared with current use, recent discontinuation was associated with a clinically and statistically significant increase in risk of nonfatal MI and in the combined outcome of death from CHD and nonfatal MI. There was no significant difference in risk of CHD death alone.
Risk of Major Cardiovascular Events in Those Who Discontinued vs Those Who Continued Aspirin
| Event | Rate ratio (95% CI) |
| Nonfatal MI | 1.63 (1.23–2.14) |
| MI/CHD death | 1.43 (1.12–1.84) |
The authors note that these results support those of previous studies in secondary care and show that they are applicable to the general population. "Reducing the number of patients who discontinue low-dose aspirin could have a major impact on the benefit obtained with low-dose aspirin in the general population," they add. They call for further research to test whether efforts to encourage patients to continue prophylactic treatment with low-dose aspirin will decrease MI rates.
q"Any day off aspirin is a day at risk for patients with previous cardiovascular disease."
In an accompanying editorial [2], Dr Giuseppe Biondi-Zoccai (University of Modena, Italy) and Dr Giovanni Landoni (Università Vita-Salute San Raffaele, Milan, Italy) write: "any day off aspirin is a day at risk for patients with previous cardiovascular disease."
But the editorialists note that some patients may not be able to take aspirin because of bleeding risk, and that the risk-benefit ratio of aspirin in individual patients should always be considered. But in general, "patients on chronic low-dose aspirin for secondary prevention of cardiovascular disease should be advised that unless severe bleeding ensues or an informed colleague explicitly says so, aspirin should never be discontinued given its overwhelming benefits on atherothrombosis, as well as colorectal cancer and venous thromboembolism."
They add: "Accordingly, doctors should maintain their patients on low-dose aspirin as long as they can and carefully assess individual patients for the risk of both thrombosis and bleeding before discontinuing aspirin for invasive procedures. Patients who need to discontinue aspirin should do so for the minimum time necessary."
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου