Quantifying the Interaction Between ACE Inhibitors and Aspirin
Quantifying the Interaction Between ACE Inhibitors and Aspirin
Angiotensin-converting enzyme (ACE) inhibitors reduce mortality in patients with heart failure and coronary artery disease. Recently, there has been growing concern about the possible interaction between ACE inhibitors and aspirin. Numerous investigators have addressed this issue; however, results are equivocal. Most researchers used a statistical test of interaction, but the use of this method has been criticized. To assess the interaction between ACE inhibitors and aspirin properly, an additive model -- more specifically, the Rothman Synergy Index -- should be used. Further investigation with this model, however, is needed.
Angiotensin-converting enzyme (ACE) inhibitors are the drugs of first choice in patients with chronic heart failure. However, recently, clinicians have been hesitant to prescribe ACE inhibitors with aspirin due to the potential of an interaction. The mechanism behind this interaction is thought to be due to the inhibition of prostaglandins by aspirin. The inhibition may lead to sodium and water retention, thus attenuating the effect of the ACE inhibitor. Several studies, including a meta-analysis, attempted to shed light on the possible interaction between the two drugs, with conflicting results. A recent study failed to show an interaction between the two drugs. That study had strong methodology including a large sample size and adjustment for potential confounders. The authors concluded that clinicians should not deprive patients of the potential benefit of both drugs. Do we finally have convincing evidence on the lack of an interaction between ACE inhibitors and aspirin? I do not believe so. In fact, we are far from having an answer to this question.
The limitation in almost all of the studies that attempted to answer this question is the use of a statistical test of interaction. This test is an inappropriate method to quantify an interaction between two independent factors and has been criticized. A more appropriate method is the Rothman Synergy Index, which is based on an additive model.
Angiotensin-converting enzyme (ACE) inhibitors reduce mortality in patients with heart failure and coronary artery disease. Recently, there has been growing concern about the possible interaction between ACE inhibitors and aspirin. Numerous investigators have addressed this issue; however, results are equivocal. Most researchers used a statistical test of interaction, but the use of this method has been criticized. To assess the interaction between ACE inhibitors and aspirin properly, an additive model -- more specifically, the Rothman Synergy Index -- should be used. Further investigation with this model, however, is needed.
Angiotensin-converting enzyme (ACE) inhibitors are the drugs of first choice in patients with chronic heart failure. However, recently, clinicians have been hesitant to prescribe ACE inhibitors with aspirin due to the potential of an interaction. The mechanism behind this interaction is thought to be due to the inhibition of prostaglandins by aspirin. The inhibition may lead to sodium and water retention, thus attenuating the effect of the ACE inhibitor. Several studies, including a meta-analysis, attempted to shed light on the possible interaction between the two drugs, with conflicting results. A recent study failed to show an interaction between the two drugs. That study had strong methodology including a large sample size and adjustment for potential confounders. The authors concluded that clinicians should not deprive patients of the potential benefit of both drugs. Do we finally have convincing evidence on the lack of an interaction between ACE inhibitors and aspirin? I do not believe so. In fact, we are far from having an answer to this question.
The limitation in almost all of the studies that attempted to answer this question is the use of a statistical test of interaction. This test is an inappropriate method to quantify an interaction between two independent factors and has been criticized. A more appropriate method is the Rothman Synergy Index, which is based on an additive model.
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