APPLYING DIFFERENT RESEARCH METHODOLOGIES TO ORAL ANTICOAGULANT MANAGEMENT RESEARCH

Abstract

Background and Objectives Oral anticoagulants (OACs) are among Canada's most frequently prescribed drugs and a top cause of medication-related serious harm leading to emergency department visits, hospitalizations, and fatalities. During the preparation to launch a Canadian Institutes of Health Research (CIHR)-funded randomized controlled trial (RCT) called "Improving Anticoagulant Safety at Hospital Discharge: A Randomized Trial," we faced some issues. First, as the RCT addresses OAC management, we needed to determine the barriers and facilitators for optimal OAC management, which were not identified in our literature search. Second, there is no core outcome set (COS) specific for OACs and the choice of outcomes and their measurement for the trial was not obvious. Finally, the drug-drug interactions between the OACs and other medications are not fully understood, particularly with regards to important clinical outcomes. Identifying the interacting medications and their interaction effect size, is vital to guarantee the safety of patients. To address these issues, the objectives of this thesis were: (1) to determine the barriers and facilitators for optimal OAC management, (2) to define the potential list for the COS of OACs, and (3) to explore the drug-drug interaction of OACs. Methods Several research approaches, including a systematic review, a systematic survey, a scoping review, a population-based retrospective cohort study with time varying methods, and a qualitative study were applied in this thesis. First, we applied both a synthesis review and qualitative research to explore the barriers and facilitators for OACs management to guarantee the evidence's robustness. Next, we used a systematic survey to address the lack of consensus on outcomes used and their v definitions for OAC treatment clinical trials. Finally, we used a systematic review and planned a population-based study to address drug-drug interaction related to OACs. Methodologic challenges and innovation In the scoping review (Chapter 2: Barriers and facilitators to optimal oral anticoagulant management: a scoping review) and the focus group study (Chapter 3: Perceptions on patient education to improve oral anticoagulant management) we employed a qualitative approach. The main methodological challenge for both the scoping review and the focus group focused on the rigorous way to synthesize the themes. In Chapter 4, we used a systematic survey to explore the outcome list for OAC management research. The primary methodological challenge referred to the outcome reporting in the included studies. Not all outcomes performed in the trials can be reported for the space limitation or potential publication bias. In Chapters 5 and 6, a systematic review with meta-analysis and an observational protocol were used to explore the drug-drug interaction for OACs. The main methodological challenge for Chapter 5 was how to evaluate the drug-drug interaction (DDI) evidence systematically. The main methodological challenge for Chapter 6 is to address confounding and bias in a population-based protocol on DOACs drug-drug interaction. Conclusion In summary, this standard thesis describes five different background projects to prepare for an OAC management RCT. The papers contribute to the literature by using several research methodologies to provide useful evidence for OAC management and OAC research.