Email updates

Keep up to date with the latest news and content from BMC Health Services Research and BioMed Central.

Open Access Study protocol

Impact of effectiveness information format on patient choice of therapy and satisfaction with decisions about chronic disease medication: the "Influence of intervention Methodologies on Patient Choice of Therapy (IMPACT)" cluster-randomised trial in general practice

Charlotte Gry Harmsen1*, Dorte Ejg Jarbøl1, Jørgen Nexøe1, Henrik Støvring2, Dorte Gyrd-Hansen3, Jesper Bo Nielsen3, Adrian Edwards4 and Ivar Sønbø Kristiansen15

Author Affiliations

1 Research Unit of General Practice, University of Southern Denmark, Southern Denmark, Denmark

2 Department of Public Health, Biostatistics, Aarhus University, Aarhus, Denmark

3 Institute of Public Health, University of Southern Denmark, Southern Denmark, Denmark

4 Cochrane Institute of Primary Care & Public Health, School of Medicine, Cardiff University, Wales, UK

5 Department of Health Management and Health Economics, University of Oslo, Oslo, Norway

For all author emails, please log on.

BMC Health Services Research 2013, 13:76  doi:10.1186/1472-6963-13-76

Published: 25 February 2013

Abstract

Background

Risk communication is an integral part of shared decision-making in health care. In the context of interventions for chronic diseases it represents a particular challenge for all health practitioners. By using two different quantitative formats to communicate risk level and effectiveness of a cholesterol-lowering drug, we posed the research question: how does the format of risk information influence patients’ decisions concerning therapy, patients’ satisfaction with the communication as well as confidence in the decision. We hypothesise that patients are less prone to accept therapy when the benefits of long-term intervention are presented in terms of prolongation of life (POL) in months compared to the absolute risk reduction (ARR). We hypothesise that patients presented with POL will be more satisfied with the communication and confident in their decision, suggesting understanding of the time-related term.

Methods/Design

In 2009 a sample of 328 general practitioners (GPs) in the Region of Southern Denmark was invited to participate in a primary care-based clinical trial among patients making real-life clinical decisions together with their GP. Interested GPs were cluster-randomised to inform patients about cardiovascular disease (CVD) risk and the effectiveness of statin therapy using either POL or ARR. The GPs attended a training session before informing their patients. Before training and after the trial period they received a questionnaire about their attitudes to risk communication and the use of numerical information. Patients’ redemptions of statin prescriptions will be registered in a regional prescription database to evaluate a possible association between redemption rates and effectiveness format. The Combined Outcome Measure for Risk Communication And Treatment Decision Making Effectiveness (COMRADE) questionnaire will be used to measure patients’ confidence and satisfaction with the risk communication immediately after the conversation with their GPs.

Discussion

This randomised clinical trial compares the impact of two effectiveness formats on real-life risk communication between patients and GPs, including affective patient outcomes and actual choices about acceptance of therapy. Though we found difficulties in recruiting GPs, according to the study protocol we have succeeded in engaging sufficient GPs for the trial, enabling us to perform the planned analyses.

Trial registration

ClinicalTrials.gov Protocol Registration System http://ww.clinicaltrials.gov/NCT01414751 webcite

Keywords:
RCT; Shared decision making; Risk communication; Prognosis; Absolute risk reduction; Prolongation of life; Cardiovascular disease; Primary prevention; Health behaviour; General practice