June 11, 2015
2 min read

GI bleeding risk higher with novel anticoagulants than warfarin in older patients

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Gastrointestinal bleeding risk is similar for patients assigned novel oral anticoagulants and warfarin, but clinicians should use caution when prescribing the new agents to those older than 75 years, according to research published in The BMJ.

“By using the real-world, national data available from the Optum Labs Data Warehouse, we were able to determine that individuals over age 75 have a much higher risk of GI bleeds than younger patients, if using dabigatran or rivaroxaban instead of warfarin,” Neena S. Abraham, MD, of the Mayo Clinic, Scottsdale, Arizona, said in a news release. “Our findings definitely point toward important age-related risk that merits consideration when doctors are making treatment recommendations.”

Neena S. Abraham

Neena S.

Abraham and colleagues retrospectively identified 92,816 patients with and without atrial fibrillation through the database of administrative claims who initiated anticoagulation therapy during a 3-year period; 8,578 (9.2%) were assigned dabigatran (Pradaxa, Boehringer Ingelheim), 16,253 (17.5%) rivaroxaban (Xarelto, Janssen Pharmaceuticals) and 67,985 (73.2%) warfarin.

The researchers used incidence rates (events/100 patient-years) and propensity score matching Cox proportional hazards models to estimate total, upper and lower GI bleeds with novel oral anticoagulants compared with warfarin. Using a marginal effects model, the team examined heterogeneity of treatment effect related to age.

Among patients with AF, the incidence of GI bleeding was less often associated with dabigatran (2.29; 95% CI, 1.88-2.79) than warfarin (2.87; 95% CI, 2.41-3.41). However, GI bleeding occurred more often in patients with non-AF with dabigatran (4.1; 95% CI, 2.47-6.8) compared with warfarin (3.71; 95% CI, 2.16-6.4; see Table for HRs).

Patients with AF were similarly less likely to experience GI bleeding with rivaroxaban (2.84; 95% CI, 2.3-3.52) than warfarin (3.06; 95% CI, 2.49-3.77). But patients with non-AF again demonstrated higher incidence with rivaroxaban (1.66; 95% CI, 1.23-2.24) than warfarin (1.57; 95% CI, 1.25-1.99; see Table for HRs).

Patients assigned new agents demonstrated increased GI bleeding risks after age 65 years, with risks exceeding those seen with warfarin by age 76 years among those with AF assigned dabigatran (HR = 2.49; 95% CI, 1.61-3.83), as well as those with and without AF assigned rivaroxaban (HR = 2.91; 95% CI, 1.65-4.81 and HR = 4.58; 95% CI, 2.4-8.72, respectively).

“The new anticoagulants have really been popular with patients who have previously only had one choice of oral anticoagulant,” Abraham said. “They greatly reduce the number of visits to the doctor for monitoring and are much more convenient for patients. However, they may not be the right choice for everyone.” – by Allegra Tiver

Disclosure: Abraham reports no relevant financial disclosures.