Novel Drug Interaction index and Risk of Mortality in Older Patients With Atrial Fibrillation Receiving Non Vitamin K Oral Anticoagulants (NOEL Drug)

Drug interactions with novel oral anticoagulants (NOACs) may decrease their advantages. We aimed to explore the drug interaction rates with NOACs and impacts of drug interaction index (DII) on mortality among older patients with atrial fibrillation (AF). In this retrospective cohort study, we enrolled 704 eligible patients aged 65≤ with AF between January 1, 2018 and December 30, 2019 in a tertiary outpatient cardiology clinic. We recorded demographic, clinical characteristics, and medications for the last 3 months. At the end of the evaluation visit (March 1, 2020), death events and dates were recorded. All medications were checked for drug interactions using Lexicomp® software. Each drug interaction was annotated according to risk grade. Moreover, we determined a new index ratio of C/D/X classes to total interactions called DII. The mean age was 75.19 ± 7.13 and 398 (56%) were male. Death events were observed in 106 (15%) patients. A total of 9883 drugs were analyzed for drug interactions. The majority of drug interactions were in class A (80.7%). Clinically relevant interactions were 14.6% (Class C/D/X). The area under receiver operating characteristic curve was 0.704 (95% confidence interval: 0.653-0.754) and 0.167 cutoff value (68.9% sensitivity and 80.2% specificity [3.11 positive likelihood ratio]) for DII to predict mortality. This study showed an overview of the NOACs interactions in older patients with AF. Additionally, the inappropriate NOAC dose and DII showed an association with mortality. NOAC treatment should be guided by drug interaction applications to reduce mortality.