A recruitment strategy for cluster randomized trials in secondary care settings

Trials of educational or organizational interventions to change clinical pr actice require cluster randomization, that is, randomization of units such as hospitals or clinical teams rather than Individual patients. Cluster ran domization is relatively novel in health care settings and raises new metho dological challenges, in particular: are units willing to be randomized at an organizational level; and, what procedures should be followed to success fully enrol all of the clinicians in a unit rather than individual clinicia ns as in conventional multicentre trials. This is particularly problematic for trials of large units such as hospitals. The aim of this study was to d evelop and partially evaluate a strategy to recruit acute, secondary carl N HS hospitals in the UK into cluster randomized trials. Literature search an d interviews with senior staff in acute hospitals and relevant national org anizations were used to develop a recruitment strategy. The strategy was ev aluated by inviting 32 randomly selected clinical directorates to participa te in a trial feasibility study. A seven step recruitment strategy was deve loped: (1) Identify stakeholders and gatekeepers; (2) Inform stakeholders a nd gatekeepers; (3) Approach gatekeepers; (4) Local negotiation; (5) Conduc t the research; (6) Feedback to gatekeepers; (7) Feedback to stakeholders. Key problems were the possibility of multiple gatekeepers and identificatio n of all possible stakeholders in varying organizational structures. The st rategy was effective in two respects. First. 32 (100%) of the directorates approached agreed to participate. Second, baseline data collection was succ essfully achieved in all of the directorates. However, the strategy is cost ly in terms of time and resources. We conclude that NHS trusts are willing to participate in cluster randomize d trials. This recruitment strategy is successful and could be widely adopt ed, but realistic time and financial cost estimates are required at the pla nning stage.