Randomised trial of the effects of omitting affective attitudes on intention to donate organs

Abstract

Background Including or excluding certain questions about organ donation may influence peoples' intention to donate. We investigated the effect of omitting certain affective attitudinal items on potential donors' intention and behaviour for donation. Methods Members of the public (n=578) participated in a cross-sectional randomised trial. Non-donors (n=349) were randomly assigned to one of three groups: Group 1 completed items on affective and cognitive attitudes, anticipated regret, intention, subjective norm and perceived behavioural control. Group 2 completed all items above but excluded affective attitudes. Group 3 completed all items but omitted negatively-worded affective attitudes. The primary outcome was intention to donate; taking a donor card after the interview was a secondary behavioural outcome. Outcomes were predicted using linear and logistic regression with group 1 as the reference. Results. Mean (SD) 1-7 intention scores for groups 1, 2 and 3 were respectively: 4.43 (SD 1.89), 4.95 (SD 1.64) and 4.88 (SD 1.81), with group 2 significantly higher than group 1 (β=0.518, 95% confidence interval [CI] 0.18 to 0.86). At the end of the interview, people in group 2 (OR=1.40, 95% CI .94 to 2.07, p=.096) but not those in group 3 (OR=1.10, 95% CI .69 to 1.75, p=.685), were marginally more likely to accept a donor card from the interviewer than people in group 1. Conclusions. Omitting affective attitudinal items results in higher intention to donate organs and marginally higher rates of acceptance of donor cards, which has important implications for future organ donation public health campaigns.