The Impact of ISO Certification Procedures on Patient Safety Culture in Public Hospital Departments

<b>Background:</b> ISO certification is widely implemented as a quality assurance tool in healthcare services; however, its impact on patient safety culture (PSC) in public hospitals remains insufficiently explored. <b>Aim:</b> This study aims to assess the effect of ISO certification procedures on different dimensions of PSC in public hospital departments by comparing ISO-certified and non-certified departments across two phases (Phase A: pre-certification; Phase B: 18 months post-certification). <b>Methods:</b> A two-phase cross-sectional study was conducted in a tertiary public hospital in Greece. Healthcare professionals from both ISO-certified and non-certified departments participated. The Hospital Survey on Patient Safety Culture (HSOPSC v1.0) was administered at two time points (Phase A: baseline, pre-certification; Phase B: 18 months post-certification). A repeated measures analysis was performed to assess the changes over time and differences between the two groups. <b>Results:</b> The findings suggest that ISO certification has a mixed impact on the PSC dimensions. A significant improvement was observed in "Supervisor's/Manager's Expectations and Actions Promoting Safety" (<i>p</i> = 0.012), while "Teamwork Within Units" (<i>p</i> = 0.026) and "Handoffs and Transitions" (<i>p</i> = 0.037) showed statistically significant changes. These results indicate that certification may enhance structured managerial oversight and interdepartmental collaboration, but at the same time, may negatively impact the teamwork within hospital units. However, no statistically significant changes were observed in "Overall Perception of Safety" (<i>p</i> = 0.135) and "Non-Punitive Response to Error" (<i>p</i> = 0.101), suggesting that while there was a trend towards a stricter safety evaluation, this was not statistically confirmed. Additionally, the staffing perceptions remained unchanged (<i>p</i> = 0.745). <b>Conclusions:</b> ISO certification appears to reinforce managerial safety expectations and interdepartmental teamwork, yet does not significantly improve the overall perceptions of patient safety or non-punitive error responses. The results indicate the need for targeted interventions to ensure that certification processes do not increase administrative burdens or negatively impact staff perceptions. Future research should explore whether these effects persist over time and how hospitals can optimize certification processes to strengthen PSC without unintended consequences.