Evidence based purchasing: understanding results of clinical trials and systematic reviews.
OBJECTIVE
To assess whether the way in which the results of a randomised controlled trial and a systematic review are presented influences health policy decisions.


METHODS
A postal questionnaire to all members of a health authority within one regional health authority.


METHODS
Anglia and Oxford regional health authorities.


METHODS
182 executive and non-executive members of 13 health authorities, family health services authorities, or health commissions.


METHODS
The average score from all health authority members in terms of their willingness to fund a mammography programme or cardiac rehabilitation programme according to four different ways of presenting the same results of research evidence--namely, as a relative risk reduction, absolute risk reduction, proportion of event free patients, or as the number of patients needed to be treated to prevent an adverse event.


RESULTS
The willingness to fund either programme was significantly influenced by the way in which data were presented. Results of both programmes when expressed as relative risk reductions produced significantly higher scores when compared with other methods (P < 0.05). The difference was more extreme for mammography, for which the outcome condition is rarer.


CONCLUSIONS
The method of reporting trial results has a considerable influence on the health policy decisions made by health authority members.
Fahey
T
T
Department of Public Health Medicine and Health Policy, Oxfordshire Health, Oxford.
Griffiths
S
S
Peters
T J
TJ
D003657:Decision Making; D004739:England; D005102:Health Expenditures; D006291:Health Policy; D006331:Heart Diseases / Q000191:economics / Q000534:rehabilitation; D006801:Humans; D008327:Mammography / Q000191:economics; D016032:Randomized Controlled Trials as Topic; D013222:State Medicine; D016896:Treatment Outcome