Co-enrollment of critically ill patients into multiple studies: patterns, predictors and consequences


INTRODUCTION Research on co-enrollment practices and their impact are limited in the ICU setting. The objectives of this study were: 1) to describe patterns and predictors of co-enrollment of patients in a thromboprophylaxis trial, and 2) to examine the consequences of co-enrollment on clinical and trial outcomes. METHODS In an observational analysis of an international thromboprophylaxis trial in 67 ICUs, we examined the co-enrollment of critically ill medical-surgical patients into more than one study, and examined the clinical and trial outcomes among co-enrolled and non-co-enrolled patients. RESULTS Among 3,746 patients enrolled in PROTECT (Prophylaxis for ThromboEmbolism in Critical Care Trial), 713 (19.0%) were co-enrolled in at least one other study (53.6% in a randomized trial, 37.0% in an observational study and 9.4% in both). Six factors independently associated with co-enrollment (all P < 0.001) were illness severity (odds ratio (OR) 1.35, 95% confidence interval (CI) 1.19 to 1.53 for each 10-point Acute Physiology and Chronic Health Evaluation (APACHE) II score increase), substitute decision-makers providing consent, rather than patients (OR 3.31, 2.03 to 5.41), experience of persons inviting consent (OR 2.67, 1.74 to 4.11 for persons with > 10 years' experience compared to persons with none), center size (all ORs > 10 for ICUs with > 15 beds), affiliation with trials groups (OR 5.59, 3.49 to 8.95), and main trial rather than pilot phase (all ORs > 8 for recruitment year beyond the pilot). Co-enrollment did not influence clinical or trial outcomes or risk of adverse events. CONCLUSIONS Co-enrollment was strongly associated with features of the patients, research personnel, setting and study. Co-enrollment had no impact on trial results, and appeared safe, acceptable and feasible. Transparent reporting, scholarly discourse, ethical analysis and further research are needed on the complex topic of co-enrollment during critical illness.

DOI: 10.1186/cc11917

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@inproceedings{Cook2013CoenrollmentOC, title={Co-enrollment of critically ill patients into multiple studies: patterns, predictors and consequences}, author={D. J. Cook and Ellen McDonald and Orla M Smith and Nicole Zytaruk and Diane M Heels-Ansdell and Irene Watpool and Tracy McArdle and Andrea L. Matt{\'e} and France J Clarke and Shirley A Vallance and Simon Finfer and Pauline Galt and Timothy M Crozier and Robert Andrew Fowler and Yaseen M Arabi and Clive Woolfe and Neil R. Orford and Richard I Hall and Neill K. J. Adhikari and Marie-Clauide Ferland and John C. Marshall and Maureen O . Meade}, booktitle={Critical care}, year={2013} }