Unannounced versus announced hospital surveys: a nationwide cluster-randomized controlled trial

Objective: To evaluate the effectiveness of unannounced versus announced surveys in detecting non-compliance with accreditation standards in public hospitals. Design: A nationwide cluster-randomized controlled trial. Setting and participants: All public hospitals in Denmark were invited. Twenty-three hospitals (77%) (3 university hospitals, 5 psychiatric hospitals and 15 general hospitals) agreed to participate. Intervention: Twelve hospitals were randomized to receive unannounced surveys (intervention group) and eleven hospitals to receive announced surveys (control group). We hypothesized that the hospitals receiving the unannounced surveys would reveal a higher degree of non-compliance with accreditation standards than the hospitals receiving announced surveys. Nine surveyors trained and employed by the Danish Institute for Quality and Accreditation in Healthcare (IKAS) were randomized into teams and conducted all surveys. Main outcome measure: The outcome was the surveyors' assessment of the hospitals' level of compliance with 113 performance indicators-an abbreviated set of the Danish Healthcare Quality Programme (DDKM) version 2, covering organizational standards, patient pathway standards and patient safety standards. Compliance with performance indicators was analyzed using binomial regression analysis with bootstrapped robust standard errors. Results: In all, 16 202 measurements were acceptable for data analysis. The risk of observing noncompliance with performance indicators for the intervention group compared with the control group was statistically insignificant (risk difference (RD) = -0.6 percentage points [-2.51-1.31], P = 0.54). A converged analysis of the six patient safety critical standards, requiring 100% compliance to gain accreditation status revealed no statistically significant difference (RD = -0.78 percentage points [-4.01-2.44], P = 0.99). Conclusions: Unannounced hospital surveys were not more effective than announced surveys in detecting quality problems in Danish hospitals.