RADAR-Septic Shock: A Population-Based Surveillance and Risk-Adjusted Benchmarking System for Septic Shock in Catalonia

Background: We established RADAR-Septic Shock (Registry of Administrative Data Automatically Recorded for Septic Shock) as a population-based surveillance system to monitor the epidemiology, healthcare utilization, clinical outcomes, and risk-adjusted performance of septic shock across the Catalan publicly funded healthcare system. Methods: A retrospective population-based study was conducted using the CMBD-HA administrative database, including all public hospital discharges coded for septic shock (ICD-10-CM codes R65.21 and T81.12XA) in Catalonia between 2018 and 2024. Variables included demographic characteristics, comorbidities, source of infection, setting of acquisition, organ dysfunctions, and advanced organ support. Mortality risk was assessed using multivariable logistic regression, and model performance was evaluated using the area under the receiver operating characteristic curve (AUROC) and the area under the precision-recall curve (AUPRC). Hospital benchmarking was based on observed-to-expected (O/E) mortality ratios. Results: Between 2018 and 2024, RADAR-Septic Shock captured 37,855 episodes of septic shock. In 2024, 6522 episodes were recorded, corresponding to an incidence of 80.28 cases per 100,000 inhabitants per year. Overall, 79% of episodes were community-acquired and 21% hospital-acquired. Patients were predominantly male (60%), with a mean age of 68.7 years, and 57% had a high-risk comorbidity profile. Overall in-hospital mortality was 36.7%, increasing to 49.5% in hospital-acquired septic shock. Among patients with available APACHE II scores, mortality progressively declined across all severity categories over the study period, except during the COVID-19 pandemic. The mortality prediction model demonstrated acceptable discrimination (AUROC: 0.739; 95% CI: 0.726–0.752; AUPRC: 0.554). Risk-adjusted benchmarking identified substantial variation in outcomes across hospitals and territorial clusters. Conclusions: RADAR-Septic Shock provides a standardized population-based surveillance framework for monitoring the epidemiology, healthcare utilization, clinical outcomes, and risk-adjusted performance of septic shock. In Catalonia, it identified an annual incidence of approximately 80 cases per 100,000 inhabitants and documented improving mortality over time, except during the COVID-19 pandemic. By enabling risk-adjusted benchmarking across healthcare institutions, RADAR-Septic Shock may support quality-improvement initiatives, healthcare planning, and sepsis policy development.