Local Researchers Changing the Game Post Hip & Knee Replacement

Dr. David Anderson (Photo: Bruce Bottomley, courtesy Dalhousie)

Nova Scotia Health Authority (NSHA) and Dalhousie University researchers are changing the way we prevent venous thromboembolism (blood clots) after hip and knee replacement surgery. The EPCAT II Study (Extended Venous Thromboembolism Prophylaxis Comparing Rivaroxaban to Aspirin Following Total Hip and Knee Arthroplasty II) found that there was no significant differences between widely available, inexpensive Aspirin and current standard of care Rivaroxaban after total hip or total knee arthroplasty. The team was recently published in New England Journal of Medicine (NEJM).

"This large, randomized, double-blind trial is likely to be practice-changing, because the point estimates for the relative safety and efficacy of the two treatments are precise and the included patients represent a typical population undergoing joint-replacement surgery." says Dr. David Garcia who commented on the results in an NEJM Editorial.

Lead author Dr. David Anderson (Dalhousie University Dean of Medicine), Dr. Michael Dunbar (NSHA Orthopedic Surgeon, Researcher and QEII Foundation Endowed Chair in Arthroplasty Outcomes) and their research teams at NSHA completed an interdisciplinary study between orthopaedics and hematology. The study was a joint effort conducted at 14 other institutions across several provinces (NS, ON, QC, NB, MB) and many participating sites commended NSHA Hematology Research Manager Susan Pleasance and her team on their excellent study management. NSHA's Research Methods Unit (RMU) contributed with sample size calculation, analytic design and analysis of all results. They also contributed to data management activities of the study, including database consulting and design, data reporting, data cleaning and preparation for analysis.

This was an exceptional example of a large, interdisciplinary, inter provincial and multi-site cooperative research study.

The EPCAT II trial recruited patients from January 2013 through April 2016 and followed 3424 patients post knee and hip replacement in a multicentre, double blind, randomized control trial funded by CIHR.All enrolled patients had an initial 5 day course of Rivaroxaban, then randomized to continue on Rivaroxaban or switch to Aspirin for additional 9 days (knee-1620 patients) or 30 days (hip-1804 patients) and followed for 90 days post surgery. 

The primary effectiveness outcome was the rate of symptomatic venous thromboembolism. Results show that the rates were similar between the two drugs. The primary safety outcome was a major or clinically important bleeding event both of which were also similar between the two drugs.


The EPCAT II trial builds on the EPCAT I trial which suggested that extended prophylaxis with Aspirin after total hip replacement was as safe and effective as heparin to prevent venous thromboembolism after an initial 10-day postoperative course of heparin.

"Going forward, the very low rates of bleeding and thrombosis seen with the relatively inexpensive and user-friendly aspirin-based strategy probably mean that the EPCAT II trial has established a prophylaxis regimen against which all strategies to prevent venous thromboembolism after joint replacement will be compared." (Dr. David Garcia)


Additional Media:

• QEII Foundation- CTV House Calls: video from 2016
• NEJM video summarizing the research findings

Welcome Prosper Koto

We welcome our new RMU Health Economist- Prosper Koto! 

Prosper Koto joined NSHA in early November 2017 as a member of the Research Methods Unit (RMU). He graduated from the University of Manitoba with a PhD in Economics specializing in Applied Econometrics and Applied Microeconomics, and also has an MSc. from the University of Guelph. 

Prior to joining the RMU, he taught in the Department of Economics at the Dalhousie University for a year. He also has extensive teaching experience from the University of Manitoba. His experience in health economics research comes from conducting independent research on multivalued treatment effects analysis using observational data and he also was part of a team working on a Manitoba Research Alliance project evaluating the effect of the availability of Video Lottery Terminals on the health and economic outcomes of individuals in various communities in Manitoba. He has additional research experience from single-authored peer-reviewed journal publications. 

He is available for consultation on economic evaluation of health care programs/treatments/interventions, including research design, cost effectiveness and cost utility analysis, either as part of a clinical trial, using observational data or using decision analytic models. He is also available for consultation on multivalued treatment effect analysis using econometric techniques, and econometric analysis of health data including longitudinal data. 

Please join us in welcoming Prosper to NSHA!

Q&A with the RMU

What’s the most requested service you provide to researchers? 

RMU Staff:  Joe Fraser, Chris Theriault,
Daniela Meier, Olga Kits & Steve Doucette

Researchers often contact the RMU for database support and biostatistical consulting. Typically, these two services go hand in hand as our database specialists know very well how the data needs to be laid out in a database, in order to create an analytical dataset that can be easily imported into a statistical software program. Over the last year, we have seen increases in requests for qualitative methods support and health economic consulting. We anticipate this trend to continue. More researchers are interested in a health economic evaluation of their intervention in order to assess additional benefits beyond immediate patient outcomes. This is an important consideration from a healthcare system perspective.

What’s the newest thing at the RMU? 

The newest support available to researchers via the RMU is REDCap. REDCap, is a free, secure, web-based application for building and managing online surveys and databases for research studies. It was introduced at the NSHA earlier this year and is available to all NSHA-affiliated researchers. REDCap presents a much more sophisticated option for high quality and secure data capture compared to commonly used products like Microsoft Excel or Access. To date, 2537 Institutions in 116 countries utilize it, which opens up possibilities for multi-centred research studies in Canada and beyond. Databases can be quickly developed and customized based on a study’s needs. RMU database specialists serve as REDCap administrators and oversee the creation of projects as well as management of users. The RMU will be offering two workshops in the near future to introduce researchers and research staff to REDCap to explore how it could benefit their research studies. Stay tuned for the announcements.

What is something researchers may not know about the RMU? 

One of the most common misperceptions about the RMU is that we charge for all of our services. While we do charge for some of our services, there is a significant number of services that we provide for free. They include the one-hour initial consult, all preparatory work required for the duration of a project, support for research design and methods refinement, initial support in the context of a grant application and development of Statement of Work. We encourage researchers to look for funding opportunities and include our services in their budgets in consultation with our consultants. You can find more specific information about our services on our website. http://www.cdha.nshealth.ca/rmu