Background Quality collaboratives are widely endorsed as a potentially effective method for translating and spreading best practices for acute myocardial infarction (AMI) care. Nevertheless, hospital success in improving performance through participation in collaboratives varies markedly. We sought to understand what distinguished hospitals that succeeded in shifting culture and reducing 30-day risk-standardised mortality rate (RSMR) after AMI through their participation in the Leadership Saves Lives (LSL) collaborative.

Procedures We conducted a longitudinal, mixed methods intervention study of 10 hospitals over a 2-year period; data included surveys of 223 individuals (response rates 83%–94% depending on wave) and 393 in-depth interviews with clinical and management staff most engaged with the LSL intervention in the 10 hospitals. We measured change in culture and RSMR, and key aspects of working related to team membership, turnover, level of participation and approaches to conflict management.

Main findings The six hospitals that experienced substantial culture change and greater reductions in RSMR demonstrated distinctions in: (1) effective inclusion of staff from different disciplines and levels in the organisational hierarchy in the team guiding improvement efforts (referred to as the ‘guiding coalition’ in each hospital); (2) authentic participation in the work of the guiding coalition; and (3) distinct patterns of managing conflict. Guiding coalition size and turnover were not associated with success (p values>0.05). In the six hospitals that experienced substantial positive culture change, staff indicated that the LSL learnings were already being applied to other improvement efforts.

Principal conclusions Hospitals that were most successful in a national quality collaborative to shift hospital culture and reduce RSMR showed distinct patterns in membership diversity, authentic participation and capacity for conflict management.