RESUMO
SETTING: Clinical trials can provide a high standard of patient care and contribute to scientific knowledge; however, only a fraction of the patients screened participate and receive treatment as part of a trial. OBJECTIVE: To explore reasons why patients were not enrolled in an international tuberculosis (TB) treatment trial and to compare experiences among study sites. DESIGN: An analysis of reasons why patients were not enrolled was conducted among patients screened for a TB clinical trial at 26 sites in North and South America, Africa, and Europe. RESULTS: Staff at study sites screened 1119 potential candidates for the trial: 61% (n = 686) were not enrolled due to 1) failure to meet eligibility criteria (n = 405, 59%), 2) site's decision (n = 168, 24%), or 3) candidate's choice (n = 113, 16%). Study staff recorded a total of 144 reasons for why they believed patients chose not to participate, including concerns over research (28%), conflicts with work or school (21%), and lifestyle and family issues (20%). Socio-demographic and geographic factors also influenced participation. CONCLUSION: Increased evaluation of screening outcomes and of specific interventions, such as improved education and communication about trial procedures, may increase the efficiency of screening and enrollment in clinical trials.