Are you busy for the next 5 years? Recruitment in the Childhood Asthma Prevention Study (CAPS)

Objective: The process of recruitment into randomized controlled trials is not often reported. in the present paper, the methods used for recruitment into the Childhood Asthma Prevention Study are reported and the reasons why eligible subjects chose not to participate or withdrew from the trial are examined. Methodology: Recruitment was conducted at the antenatal clinics of six hospitals in Sydney (NSW, Australia). Pregnant women with a family history of asthma who consented to participate were randomized into one of four groups and were asked to follow a set of interventions. The study will continue until the infants are 5 years old. Results: Of 7171 women screened, 2095 (29.2%) were eligible, of whom only 616 (29.4% of eligible women) were recruited. The main reasons for not taking part in the study were a lack of interest, ineligibility (on further questioning), inability to be contacted and 'too busy'. During the first 21/2 years of the trial, 10% of participants withdrew. The most common reasons for withdrawal from the study were loss of contact, family moving interstate or overseas and medical reasons. In families that withdrew from the trial or who were eligible but did not participate, the parents were significantly younger, mothers were less educated and fathers were less likely to be in full-time employment. Conclusions: By collecting demographic data on people who withdrew from the study and chose not to participate, we gained a better understanding of why our recruitment rate was low. The preferential recruitment of some sectors of the community has important implications for the ways in which future studies will be planned.