Prospectively screening for eligible patients was inaccurate in predicting patient recruitment of orthopedic randomized trials

OBJECTIVE: To compare the accuracy of estimates of potential recruitment from a prospective 8-week screening study compared with a retrospective chart review across sites participating in two fracture management trials. STUDY DESIGN AND SETTING: During the planning phase of two large, multicenter, randomized controlled fracture management trials, 74 clinical sites provided estimates of the annual recruitment rate both retrospectively (based on chart reviews) and prospectively. The prospective estimate was generated by screening, for 8 weeks, all incoming patients for eligibility in the concerning trial, without actually enrolling any patient. We compared these prospective and retrospective estimates with one another (for 74 sites in the two trials) and with actual 1-year recruitment rates in the definitive trial (for nine sites in one trial). RESULTS: There was a median difference of four patients (interquartile range: -14 to 18 patients; P=0.89) between a center's prospective estimate and its retrospective estimate. Both predictions were overestimations of recruitment in the definitive trial; only 31% (95% confidence interval [CI]: 28, 35) of retrospectively estimated patients, and 31% (95% CI: 27, 35) of prospectively estimated patients were recruited in the definitive trials. CONCLUSION: Compared with relatively simple chart reviews, prospectively screening for eligible patients at clinical sites, which is associated with substantial costs, did not result in more accurate predictions of accrual in large, multicenter, randomized controlled trials.