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Risk of Gastrointestinal Bleeding Increases With Combinations of Antithrombotic Agents and Patient Age
Neena S Abraham1, Peter A Noseworthy2, Jonathan Inselman3
1Division of Gastroenterology and Hepatology, Department of Medicine, Mayo Clinic, Scottsdale, Arizona; Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, Minnesota; Division of Health Care Policy and Research, Mayo Clinic, Rochester, Minnesota.
Insights
Combination antithrombotic therapy increases gastrointestinal bleeding (GIB) risk, particularly in patients over 75. Monotherapy with anticoagulants or antiplatelets showed similar GIB rates.
Area of Science:
- Cardiovascular Medicine
- Pharmacology
- Gastroenterology
Background:
- Determining the safety of various antithrombotic strategies is crucial for patients requiring these medications.
- Gastrointestinal bleeding (GIB) is a significant risk associated with antithrombotic therapies.
- Previous research has not fully elucidated the comparative safety profiles of different antithrombotic regimens.
Purpose of the Study:
- To investigate the risk and temporal patterns of gastrointestinal bleeding (GIB) in patients using different antithrombotic drug regimens.
- To evaluate whether GIB risk increases over time and with combination therapies, especially in elderly populations.
Main Methods:
- Retrospective analysis of nationwide claims data from privately insured and Medicare Advantage enrollees (October 2010 - May 2017).
- Patients were stratified by antithrombotic prescription: anticoagulant alone, antiplatelet alone, or combination therapy.
- One-year GIB risk was estimated using parametric time-to-event survival models, calculating annualized risk and number needed to harm (NNH).
Main Results:
- Combination antithrombotic therapy significantly increased GIB risk compared to monotherapy (NNH 29 for anticoagulant, 31 for antiplatelet).
- No significant difference in GIB rates was observed between anticoagulant and antiplatelet monotherapy (approximately 3.5% per year).
- GIB risk escalated with age, particularly in patients over 75 years on combination therapy (10%-17.5% annually).
Conclusions:
- Combination antithrombotic therapy poses a higher risk of gastrointestinal bleeding than monotherapy.
- The risk of GIB increases with advancing age, with the highest risk observed in patients over 75 years on combination therapy.
- These findings highlight the importance of age and combination therapy in assessing GIB risk in patients on antithrombotics.
Background & Aims:
The safety of different antithrombotic strategies for patients with 1 or more indication for antithrombotic drugs has not been determined. We investigated the risk and time frame for gastrointestinal bleeding (GIB) in patients prescribed different antithrombotic regimens. We proposed that risk would increase over time and with combination regimens, especially among elderly patients.
Methods:
We performed a retrospective analysis of nationwide claims data from privately insured and Medicare Advantage enrollees who received anticoagulant and/or antiplatelet agents from October 1, 2010, through May 31, 2017. Patients were stratified by their prescriptions (anticoagulant alone, antiplatelet alone, or a combination) and by their primary diagnosis (atrial fibrillation, ischemic heart disease, or venous thromboembolism). The 1-year GIB risk was estimated using parametric time-to-event survival models and expressed as annualized risk and number needed to harm (NNH).
Results:
Our final analysis included 311,211 patients (mean ages, 67 years for monotherapy and 69.8 years for combination antithrombotic therapy). There was no significant difference in the proportion of patients with bleeding after anticoagulant or antiplatelet monotherapy (∼3.5%/year). Combination antithrombotic therapy increased GIB risk compared with anticoagulant (NNH, 29) or antiplatelet (NNH, 31) monotherapy, regardless of the patients' diagnosis or time point analyzed. Advancing age was associated with increasing 1-year probability of GIB. Patients prescribed combination therapy were at the greatest risk for GIB, especially after the age of 75 years (GIB occurred in 10%-17.5% of patients/y).
Conclusions:
In an analysis of nationwide insurance and Medicare claims data, we found GIB to occur in a higher proportion of patients prescribed combinations of anticoagulant and antiplatelet agents compared with monotherapy. Among all drug exposure categories and cardiovascular conditions, the risk of GIB increased with age, especially among patients older than 75 years.
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