Increased Risk of Intracranial Hemorrhage in Older Patients Exposed to Multidrug Interactions Involving Warfarin

Multidrug interactions are a major cause of mortality for older patients. With an increase in "alert fatigue" for clinicians using Electronic Health Record systems (EHRs), Adverse Drug Events (ADEs) are increasing within older populations taking various drugs, because the probabilities of the adverse events associated with exposure to interacting drugs are not provided. The Observational Health Data Sciences and Informatics (OHDSI) ATLAS tool was utilized with Columbia University Irving Medical Center (CUIMC) patient data to determine whether Intracranial Hemorrhage (ICH) risk increases after being exposed to various multidrug interactions involving Warfarin in patients aged 60-90 years old one week before an ICH occurrence in patients prescribed ranges of 1-5, 6-10, and 11-15 drugs to also see the impact of polypharmacy on the prevalence of ICH amongst these patients. The prevalence of ICH in patients exposed to two and three-drug combinations involving Warfarin, Aspirin, Acetaminophen, and Amiodarone was measured. Significant increases in ICH risk and prevalence were identified in patients who had taken various combinations of these drugs with three-drug combinations involving Warfarin having a higher ICH risk than two-drug combinations involving Warfarin. Other findings also include that patients prescribed a larger number of drugs also tended to have a higher ICH risk than those prescribed a smaller number of drugs. Understanding the prevalence of such ADEs have crucial implications in the healthcare system, as the increased probabilities for certain ADEs from multidrug combinations can be applied to future EHR systems to counteract "alert fatigue" issues.