Risk of Hospitalized Gastrointestinal Bleeding in Persons Randomized to Diuretic, ACE-Inhibitor, or Calcium-Channel Blocker in ALLHAT

Calcium channel-blockers (CCB) are an important class of medication useful in the treatment of hypertension. Several observational studies have suggested an association between CCB therapy and gastrointestinal hemorrhage. Using administrative databases, we re-examined in a post-hoc analysis whether the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) participants randomized to the calcium-channel blocker amlodipine had a greater risk of hospitalized gastrointestinal bleeding (a pre-specified outcome) compared to those randomized to the diuretic chlorthalidone or the ACE-inhibitor lisinopril. Participants randomized to chlorthalidone did not have a reduced risk for gastrointestinal bleeding hospitalizations compared to participants randomized to amlodipine (HR, 1.09, 95% CI 0.92-1.28). Those randomized to lisinopril were at increased risk of gastrointestinal bleeding compared those randomized to chlorthalidone (HR, 1.16; 95% CI, 1.00-1.36). In a post-hoc comparison, participants assigned lisinopril therapy had a higher risk of hospitalized gastrointestinal hemorrhage (HR,1.27, 95% CI 1.06-1.51) versus those assigned to amlodipine. In-study use of atenolol prior to first gastrointestinal hemorrhage was related to a lower incidence of GI bleeding (HR, 0.69; 95% CI, 0.57-0.83). In conclusion, hypertensive patients on amlodipine do not have an increased risk of GI bleeding hospitalizations compared to those on either chlorthalidone or lisinopril.