Effect of PDCA cycle on critical value management in primary healthcare institutions: an interrupted time series study

Background Critical value management represents a core component of medical safety, yet primary healthcare institutions continue to face challenges including non-standardized processes, incomplete documentation, and insufficient IT support. Although the PDCA cycle is widely adopted as a quality management tool, most evaluations of its effectiveness rely on simple pre-post comparisons, failing to distinguish true intervention effects from underlying secular trends. Methods We conducted a prospective, multicenter study implementing a 24-month PDCA cycle intervention across 62 primary healthcare institutions in Jiangsu Province. Quality improvement initiatives included implementing a unified Critical Value Reporting Protocol, standardizing logbooks, and establishing monitoring mechanisms. We employed an interrupted time series model to analyze 24 months of data, assessing both immediate and sustained intervention effects. Results Following PDCA implementation, the standardized critical value management rate increased from a pre-intervention average of 93.8% to 98.9%. Interrupted time series analysis revealed a significant immediate improvement (OR = 1.721, p = 0.012) and a progressively strengthening trend effect (OR = 1.298, p < 0.001). The model demonstrated excellent fit with no residual autocorrelation, and statistical inferences based on robust standard errors proved reliable. Conclusion The PDCA cycle effectively enhances the standardized management of critical values in primary healthcare settings. Interrupted time series analysis provides a scientific foundation for evaluating its effectiveness. This model offers substantial operational practicality and scalability, contributing to continuous improvement in healthcare quality.