Epidemiological characteristics, SAP-associated sepsis, and prognostic analysis of persistent inflammation– immunosuppression–catabolism syndrome in severe acute pancreatitis patients after percutaneous drainage: a retrospective study

Objective This study aims to analyze the incidence and epidemiological characteristics of persistent inflammation–immunosuppression–catabolism syndrome (PICS) in severe acute pancreatitis (SAP) patients after percutaneous drainage, investigate the role of SAP-associated sepsis in PICS development, identify independent risk factors for PICS, and evaluate its impact on short- and long-term prognosis. Methods A retrospective analysis of 176 SAP patients who underwent percutaneous drainage from July 2022 to March 2025. SAP-associated sepsis was defined using the Sepsis-3 criteria (2016). Patients were categorized into PICS and non-PICS groups based on criteria assessed at postoperative day 14. Multivariate logistic regression with sepsis as a covariate identified independent PICS risk factors; Kaplan–Meier and Cox regression evaluated prognostic impact. Results PICS incidence was 37.5%. SAP-associated sepsis occurred in 78.8% of PICS patients vs. 31.8% of non-PICS patients ( p < 0.001); the median time from sepsis onset to PICS was 9.5 days (IQR 6.0–14.0). Multivariate analysis confirmed SAP-associated sepsis (OR = 2.971, 95% CI 1.390–6.348, p = 0.005) as an independent PICS risk factor alongside age, APACHE II score, sequential organ failure assessment (SOFA) score, pancreatic necrosis >50%, CRP, and procalcitonin; preoperative albumin was protective. The integrated prediction model (AUC = 0.891) improved upon the model excluding sepsis (AUC = 0.876). PICS patients had a 6-month survival rate of 72.7% vs. 95.5% ( p < 0.001), and PICS was an independent risk factor for post-discharge mortality (HR = 4.823, p < 0.001). Conclusion SAP patients after percutaneous drainage have a high PICS incidence (37.5%). SAP-associated sepsis was strongly and independently associated with PICS development, with the median sepsis-to-PICS interval of approximately 9.5 days, suggesting a potential period of heightened vulnerability warranting further prospective investigation. PICS substantially worsens prognosis, underscoring the need for early identification and targeted immunomodulatory and nutritional interventions in SAP patients with concurrent sepsis.