RECRUITING HEALTHY PARTICIPANTS FOR A LARGE CLINICAL-TRIAL

The Lung Health Study (LHS) is a multicenter randomized clinical trial evaluating treatments for the prevention of chronic obstructive pulmo nary disease (COPD). Participants are otherwise healthy smokers with b orderline abnormal lung function, who are at relatively high risk of d eveloping COPD. LHS recruiting efforts in the city of Winnipeg, Canada , resulted in the screening of 9,062 people (21% of age-eligible smoke rs) and randomization of 577 participants. Approximately 50% of the sc reenees were obtained by direct mail with follow-up telephone calls, w hile another 14% of the screenees were obtained at worksites. Other re cruiting methods included use of mass media, passive displays at commu nity events, and interviewer-aided mall recruiting. Screening rates (p ercent of the total age-eligible population in Winnipeg screened) were inversely related to age, although eligibility rates were directly re lated to age. Screening rate was inversely related to indicators of so cioeconomic status independent of smoking status. However, randomizati on rates (percent of the age-eligible population which was randomized) were directly related to socioeconomic status, in part because exclus ions for medical reasons were also inversely related to socioeconomic status. Eligibility at initial screening was not related to the recrui ting method, but the likelihood of randomizing eligible participants w as significantly greater at this clinic for those recruited via mass m edia and workplace screening than for those recruited by direct mail, and significantly less when recruited at community events.