This study assessed the risk of any
bleeding abnormalities, including the risk of gastrointestinal
bleeding, associated with
antidepressant exposure. We used a case-control methodology. Case patients were individuals admitted with a diagnosis of abnormal
bleeding. Control subjects were individuals admitted on the same date without evidence of abnormal
bleeding. During the study period, 11,025 case patients were admitted for
bleeding abnormalities (matched with 21,846 eligible control subjects), and 1008 were admitted for gastrointestinal
bleeding (matched with 1990 eligible control subjects). With respect to any
bleeding abnormalities,
antidepressants as a group were not associated with an increased risk (adjusted odds ratio [OR], 0.99; 95% confidence interval [CI], 0.90-1.08). Similarly,
selective serotonin reuptake inhibitors as a group, the group of tricyclic and related
antidepressants, and the group of other
antidepressants were not associated with an increased risk of
bleeding. With respect to gastrointestinal
bleeding abnormalities,
antidepressants as a group were associated with a modestly increased risk (adjusted OR, 1.34; 95% CI, 1.01-1.80). Whereas the group of tricyclic and related
antidepressants was not associated with an increased risk of
bleeding, the group of
selective serotonin reuptake inhibitors was associated with a nonsignificant trend toward an increased risk of
bleeding (adjusted OR, 1.31; 95% CI, 0.91-1.88) and the group of other
antidepressants with a statistically significant increase in the risk of
bleeding (adjusted OR, 1.74; 95% CI, 1.04-2.93). In a population with a low baseline risk of
bleeding, we detected a significant increase in the risk of gastrointestinal
bleeding only.