Abstract

Background: Privacy laws have recently created restrictions on how researchers can approach study participants.Method: In a randomised trial of 152 patients, 50–74 years old, in a family practice, 60 were randomly selected to opt-out and 92 to opt-in methods. Patients were sent an introductory letter by their doctor in two phases, opt-out before and opt-in after introduction of the new Privacy Legislation in December 2001. Opt-out patients were contacted by researchers. Opt-in patients were contacted if patients responded by email, free telephone number or a reply-paid card.Results: Opt-in recruited fewer patients after invitation compared with opt-out ; . No proportional difference in recruitment was found between opt-in and opt-out groups varied by age, sex or socioeconomic status. The opt-in group had significantly more people in active decision-making roles . Non-significant trends were observed towards opt-in being less likely to include people with lower education and people who were not screened . Opt-in was more likely to recruit people with a family history of colorectal cancer .Conclusions: The number of participants required to be approached was markedly increased in opt-in recruitment. Existing participants with a vested interest such as increased risk, and those preferring an active role in health decision making and with less education were likely to be recruited in opt-in. Research costs and generalisability are affected by implementing privacy legislation