Antidepressants can increase thinning of blood. Thus, they could prevent the building of blood clots in vessels supplying the heart or the brain with blood. Therefore, they could decrease the risk of heart attack and stroke. Moreover, some antidepressants have a stronger blood-thinning effect than others. Thus, they could be better at decreasing the risk of heart attack and stroke. However, no studies have answered this question yet. Therefore, this study will determine whether such antidepressants are related to a decreased risk of heart attack or stroke using the Clinical Practice Research Datalink. To do so, we will study patients with heart attack or stroke among users of antidepressants. Then, we will compare the number of patients with heart attack or stroke who are taking antidepressants that strongly increase thinning of blood to the number of patients who are taking antidepressants that weakly reduce thinning of blood. The findings of this study will help us better evaluate the differences between various antidepressants.
Serotonin can enhance platelet aggregation and induce vasoconstriction. Antidepressants such as the selective serotonin reuptake inhibitors may reduce thrombocyte serotonin levels. Therefore, they may inhibit platelet activation and eventually decrease thrombotic risk. Moreover, this risk may vary with the degree of serotonin inhibition of the antidepressant. Previous studies addressing this question had methodological shortcomings or were focussed on single entities of thrombotic disease. Therefore, the primary objective of this study is to determine whether the use of antidepressants strongly inhibiting serotonin reuptake is related to a decrease in the risk of ischaemic stroke and myocardial infarction using the Clinical Practice Research Datalink. For this purpose, we will assemble a cohort of patients, at least 18 years of age, newly treated with antidepressants between January 1, 1995 and June 30, 2014. Using a nested case-control approach, conditional logistic regression will be applied to compute odds ratios and 95% confidence intervals for each of the two outcomes associated with use of antidepressants with a high degree of serotonin reuptake inhibition, compared to antidepressants with a low degree of serotonin reuptake inhibition. Secondary analyses will assess the risk for each of the two outcomes according to duration of use of high affinity antidepressants.
Incidence of ischaemic stroke; Incidence of myocardial infarction.
Samy Suissa - Chief Investigator - Sir Mortimer B Davis Jewish General Hospital
Christel Renoux - Corresponding Applicant - McGill University
Antonios Douros - Collaborator - McGill University
Golsa Dehghan - Collaborator - McGill University
Jean-François Boivin - Collaborator - McGill University