Communicating effectiveness of intervention for chronic diseases: what single format can replace comprehensive information?

BMC Medical Informatics and Decision Making, Jun 2008

Background There is uncertainty about how GPs should convey information about treatment effectiveness to their patients in the context of cardiovascular disease. Hence we study the concordance of decisions based on one of four single information formats for treatment effectiveness with subsequent decisions based on all four formats combined with a pictorial representation. Methods A randomized study comprising 1,169 subjects aged 40–59 in Odense, Denmark. Subjects were randomized to receive information in terms of absolute risk reduction (ARR), relative risk reduction (RRR), number needed to treat (NNT), or prolongation of life (POL) without heart attack, and were asked whether they would consent to treatment. Subsequently the same information was conveyed with all four formats jointly accompanied by a pictorial presentation of treatment effectiveness. Again, subjects should consider consent to treatment. Results After being informed about all four formats, 52%–79% of the respondents consented to treatment, depending on level of effectiveness and initial information format. Overall, ARR gave highest concordance, 94% (95% confidence interval (91%; 97%)) between initial and final decision, but ARR was not statistically superior to the other formats. Conclusion Decisions based on ARR had the best concordance with decisions based on all four formats and pictorial representation, but the difference in concordance between the four formats was small, and it is unclear whether respondents fully understood the information they received.

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Communicating effectiveness of intervention for chronic diseases: what single format can replace comprehensive information?

BMC Medical Informatics and Decision Making Communicating effectiveness of intervention for chronic diseases: what single format can replace comprehensive information? Henrik Stovring 2 Dorte Gyrd-Hansen 0 1 Ivar S Kristiansen 2 3 Jorgen Nexoe 2 Jesper B Nielsen 1 0 Danish Institute of Health Services Research , Copenhagen, Copenhagen , Denmark 1 Institute of Public Health, University of Southern Denmark , Odense , Denmark 2 Research Unit for General Practice, University of Southern Denmark , Odense , Denmark 3 Institute of Health Economics, University of Oslo , Oslo , Norway Background: There is uncertainty about how GPs should convey information about treatment effectiveness to their patients in the context of cardiovascular disease. Hence we study the concordance of decisions based on one of four single information formats for treatment effectiveness with subsequent decisions based on all four formats combined with a pictorial representation. Methods: A randomized study comprising 1,169 subjects aged 40-59 in Odense, Denmark. Subjects were randomized to receive information in terms of absolute risk reduction (ARR), relative risk reduction (RRR), number needed to treat (NNT), or prolongation of life (POL) without heart attack, and were asked whether they would consent to treatment. Subsequently the same information was conveyed with all four formats jointly accompanied by a pictorial presentation of treatment effectiveness. Again, subjects should consider consent to treatment. Results: After being informed about all four formats, 52%-79% of the respondents consented to treatment, depending on level of effectiveness and initial information format. Overall, ARR gave highest concordance, 94% (95% confidence interval (91%; 97%)) between initial and final decision, but ARR was not statistically superior to the other formats. Conclusion: Decisions based on ARR had the best concordance with decisions based on all four formats and pictorial representation, but the difference in concordance between the four formats was small, and it is unclear whether respondents fully understood the information they received. - Background Chronic disease processes (e.g. atherosclerosis, osteoporosis, carcinogenesis) account for 8085% of all mortality in Norway and the UK (Statistics Norway, Statistics UK), and probably most industrialised countries. A considerable proportion of GPs' time is devoted to the detection and interventions related to such processes through case-finding, screening, life-style changes, pharmaceuticals or other medical interventions. In shared decision making GPs are supposed to inform patients about the effectiveness of such interventions [1]. This represents a considerable challenge to busy doctors who do not have the time to provide patients with comprehensive information about effectiveness of therapies. In practice, they may choose to provide brief information, and the question is how this is best done. While clinical trials quantify the health consequences of the interventions under ideal, controlled conditions, the effect is often diluted in realistic, noncontrolled settings, where studies have found that only few interventions yield more than 12 months in additional average life time [2]. One likely explanation is that neither patients nor doctors experience any immediate effects, except for potential side effects, and therefore patients may lose the motivation for adhering to the treatment. This is frequently the case for statins and bisphosphonates [3], where interventions often are discontinued after 12 years. In part, this suboptimal adherence may be a consequence of the patient not feeling sufficiently wellinformed about the potential benefits of adhering to treatment [4]. The standard, single formats of intervention effectiveness are: absolute risk reduction (ARR), relative risk reduction (RRR) and number needed to treat (NNT). In contrast to these formats that are measured at a specific point in time, prolongation of (disease-free) life (POL) has been suggested as a measure that summarises gain over the entire time scale. This has also been termed postponement of adverse outcomes [4]. None of these formats as such inform patients about their baseline risk, i.e. for example the heart attack risk during the subsequent 10 years. Little is known about which single format, information should have to achieve decisions that most closely reflect the decision made when the patient has received comprehensive and nuanced information, and therefore at least in theory is in a better position to make qualified decisions. While others have shown that decisions can be manipulated by framing the information in a particular format [5], we are not aware of any studies that have focused on identifying which single format(s) that leads to decisions that would be upheld when given comprehensive information. A further issue is the way in which each format is presented. ARR and RRR can be presented in te (...truncated)


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Henrik Stovring, Dorte Gyrd-Hansen, Ivar S Kristiansen, Jorgen Nexoe, Jesper B Nielsen. Communicating effectiveness of intervention for chronic diseases: what single format can replace comprehensive information?, BMC Medical Informatics and Decision Making, 2008, pp. 25, 8, DOI: 10.1186/1472-6947-8-25