OBJECTIVE: Recruitment and retention in trials may bias the results and subsequently complicate their interpretation and validity. The aim of this study is to evaluate the impact of recruitment and retention on all-cause mortality in a large all-comers trial.
METHODS: The recruitment rate in each investigating center of the GLOBAL LEADERS trial was assessed and the 130 centers were subdivided into low and high recruiters according to the median, with all-cause mortality then compared between the two groups. Vital status was obtained from public records in patients with incomplete follow-up.
RESULTS: The trial randomized 15,991 (7.86%) of 203,483 eligible patients with percutaneous coronary intervention during the recruitment period, of whom 15,267 (95.47%) completed follow-up, 23 (0.14%) patients withdrew consent and formally requested to be deleted from the database; 183 (1.14%) withdrew consent but only objected to future data collection; 303 (1.89%) discontinued the study; and 215 (1.34%) were lost to follow-up. Vital status was finally obtained in all but 31 patients (99.81%). Patients from low recruiters had a significantly lower all-cause mortality than high ones (2.26% vs. 3.24%; hazard ratio: 0.69; 95% confidence interval: 0.55-0.87; p = 0.002). There was a significant difference in all-cause mortality among the incomplete follow-up groups (log-rank p < 0.001) with a significantly higher mortality in the 183 patients who withdrew consent than those who completed follow-up (7.38% vs. 2.99%, p = 0.002).
CONCLUSIONS: Recruitment and retention significantly impacted all-cause mortality. Search for vital status through public domains is of paramount importance in the interpretation and validity of large clinical trials.