Peter Loewen

Faculty of Pharmaceutical Sciences

Research Classification

Cardiology and circulatory sciences (including cardiovascular disease)

Clinical pharmacy and pharmacy practice

Knowledge translation and implementation science in health

Population health interventions

Research Interests

atrial fibrillation

Pharmacoepidemiology

Thrombosis and Embolism

adherence to medication

Cardiovascular diseases

Arrhythmia

Heart Failure

stroke

Health Care Technologies

Professional Practices

Hematology

decision making

clinical prediction rules

hospital pharmacy practice

knowledge translation of evidence to patient care

patient complexiometry

patient decision aids

patient education

pharmacy practice

prediction of stroke and bleeding in atrial fibrillation patients

quality of care, quality drug therapy

Shared decision-making

stroke prevention therapy

use of mobile technology for clinical decision-making

Relevant Thesis-Based Degree Programs

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Research Options

I am available and interested in collaborations (e.g. clusters, grants).

I am interested in and conduct interdisciplinary research.

I am interested in working with undergraduate students on research projects.

Research Methodology

Graduate Student Supervision

Doctoral Student Supervision

Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.

Adherence to oral anticoagulants in patients with atrial fibrillation (2021)

Objective:The overall aim of this dissertation was to provide a better understanding of adherence to oral anticoagulants (OACs) in patients with atrial fibrillation (AF). Methods:Meta-analysis was used to summarize the current evidence on patients’ adherence. Population-based administrative data of British Columbia (BC) was used to develop a cohort of adults with AF. Random-effects multivariable regression modeling was used to develop and validate a method, called REWarDS, to estimate patient’s individualized daily dose of warfarin and facilitate measurement of adherence to this medication. OAC adherence was measured over follow-up by creating time windows. Group-based trajectory modeling was used to characterize adherence trajectories. Regression analyses were used to identify the factors associated with adherence, and adherence trajectories. Results:Systematic review and meta-analysis found that one year after therapy initiation patients, on average, miss 27% of their doses. REWarDS was found to be accurate with superior performance over current methods for estimating exposure to warfarin. 54% of the patients in the cohort were found to be nonadherent to their OAC, missing, on average, 32% of their doses. The greatest decline in adherence was observed in the first year of therapy. Patients were found to exhibit four distinct long-term adherence trajectories. Being on Vitamin K Antagonist (VKA) was associated with statistically significantly 13% higher adherence compared to being on Direct Oral Anticoagulants (DOAC). Over time, however, adherence increased for DOAC but decreased for VKA. Clinical and demographic factors, while readily available in administrative databases, do not have adequate discriminatory power to predict patients’ adherence trajectories. Conclusion:Adherence in patients with AF was found to be worse than previously understood. Identification of distinct long-term adherence trajectories revealed heterogeneity among nonadherent patients and compels tailoring interventions for different kinds of nonadherence patterns. Findings on the impact of drug class on adherence suggest that prescribers should not assume better adherence for DOACs based on their convenience. Overall, very few variables were identified to be independently associated with any specific adherence trajectory. Altogether, findings call for urgent interventions to improve adherence in patients with AF on both VKA and DOAC, particularly early after therapy initiation.

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Master's Student Supervision

Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.

Assessment of atrial fibrillation patients' education needs (2018)

Introduction: Education facilitates construction of a correct illness representation, corrects beliefs about medications and improves patients’ illness-treatment coherence. There is no consensus on the best education strategy for atrial fibrillation (AF) patients. Identifying patients’ education needs is the first step towards development of an effective education program.Purpose: The overall aim of this thesis was to provide insights into AF patients’ education needs from patient and clinician viewpoints, and to inform the design of AF patient education programs and initiatives.Methods: The current evidence on AF patients’ knowledge gaps was summarized through a literature review. This was followed by a qualitative descriptive study utilizing semi-structured interviews with patients and clinicians who were recruited through purposive sampling. All interviews were conducted by a Master of science student. The interviews were conducted in English, in a private room or over the phone, without the presence of any non-participants. Each interview lasted approximately 30 minutes and was audio-recorded. Verbatim transcripts were generated within three days of the interview. The reporting of this qualitative study conforms to the Standards for Reporting Qualitative Research (SQRQ) and the Consolidated Criteria for Reporting Qualitative Research (COREQ).Analysis: The analysis of the data was iterative, occurring as interviews proceeded. The interview guides were revised frequently based on the emerging data. The data collected were analyzed through inductive qualitative thematic analysis. Data from patients and clinicians were analyzed independently.Results: Eleven clinicians and ten patients were interviewed. Clinician and patient interviews led to emergence of three and four themes, respectively. This research went beyond identification of knowledge gaps by offering a rich description on patients’ misconceptions, information seeking behavior, education style preferences, attitudes towards online education, expectations of an education program, emotional education needs, preferences for risk communication, and clinicians’ views on the topic. A key finding of my study was the identification of patients’ emotional education needs: the need for education that addresses patients’ concerns and relieves their anxiety. Summarizing my study findings, I offered a set of recommendations that can be used by those involved in educating AF patients.

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Peter Loewen

Research Classification

Research Interests

Relevant Thesis-Based Degree Programs

Research Options

Research Methodology

Graduate Student Supervision

Doctoral Student Supervision

Adherence to oral anticoagulants in patients with atrial fibrillation (2021)

Master's Student Supervision

An analysis of heart failure reduced ejection fraction pharmacotherapy sequencing strategies (2023)

Oral anticoagulant switching in patients with atrial fibrillation (2022)

Assessment of atrial fibrillation patients' education needs (2018)

Publications

Membership Status

Program Affiliations

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