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)