Predictors of the effectiveness of accreditation on hospital performance: a nationwide steppedwedge study

Objective: To identify predictors of the effectiveness of hospital accreditation on process performance measures. Design: A multi-level, longitudinal, stepped-wedge, nationwide study. Participants: All patients admitted for acute stroke, heart failure, ulcers, diabetes, breast cancer and lung cancer at Danish hospitals. Intervention: The Danish Healthcare Quality Programme that was designed to create a framework for continuous quality improvement. Main outcome Measure(s): Changes in week-by-week trends of hospitals' process performance measures during the study period of 269 weeks prior to, during and post-accreditations. Process performance measures were based on 43 different processes of care obtained from national clinical quality registries. Analyses were stratified according to condition, type of care (i.e. treatment, diagnostics, secondary prevention and patient monitoring) and hospital characteristics (i.e. university affiliation, location, size, experience with accreditation and accreditation compliance). Results: A total of 1 624 518 processes of care were included. The impact of accreditation differed across the conditions. During accreditation, heart failure and breast cancer showed less improvement than other disease areas. Across all conditions, diagnostic processes improved less rapidly than other types of processes. However, after stratifying the data by hospital characteristics, process performance measures improved more uniformly. In respect of the measures that had an unsatisfactory level of quality, the processes related to diabetes, diagnostics and patient monitoring all responded to accreditation and showed an increased improvement during the preparatory work. Conclusion: Hospital characteristics were not found to be predictors for the effects of accreditation, whereas conditions and types of care to some extent predicted the effectiveness.