An Online Clinical Surveillance System to Assess the Clinical Effectiveness and Safety of Non-vitamin K Antagonist Oral Anticoagulants and Warfarin (Preprint)

Abstract

Active drug surveillance is the proactive process of assessing the adverse drug events (ADEs), but conventional systems lack a seamless workflow.

This study aims to develop a seamless and online workflow for comparing the safety and effectiveness of drugs in a database of electronic medical records.

We proposed a comprehensive integration process for clinical surveillance using the National Taiwan University Hospital Clinical Surveillance System (NCSS). We studied a practical application of the NCSS that evaluates the drug safety and effectiveness of novel oral-anticoagulants (NOACs) and warfarin by Cohort Tree Analysis in an efficient and interoperable platform.

We demonstrated a practical example of investigating the differences in effectiveness and safety between NOACs and warfarin in patients with non-valvular atrial fibrillation (AF) using the NCSS. We efficiently identified 2,357 non-valvular AF patients with newly prescribed oral anticoagulants between 2010 and 2015 and further developed one main cohort and two sub-cohorts for separately measuring ischemic stroke as the clinical effectiveness outcome and intracranial hemorrhage as the safety outcome. In the sub-cohort of ischemic stroke, NOACs users exhibited a significantly lower risk of ischemic stroke compared with warfarin users after adjusting for age, sex, comorbidity and co-medication in an intention-to-treat (ITT) analysis (P = 0.01) but exhibited a comparable risk in an as-treated (AT) analysis (P = 0.12) after the 2-year follow-up. In the sub-cohort of intracranial hemorrhage (ICH), NOACs users exhibited a comparable risk of ICH both in ITT (P = 0.68) and AT analyses (P = 0.15).

With a seamless and online workflow, the NCSS can serve the critical role of forming associations between evidence and the real world at a medical center in Taiwan.