Clinical and operational drivers of healthcare resource utilization in acute appendicitis: a real-world cohort study

Background Acute appendicitis is a high-volume emergency surgical condition and a substantial source of hospital utilization.[1, 2] Complicated appendicitis (CA) is consistently associated with longer stays and higher costs,[1, 2] yet a comprehensive, multi-outcome picture of resource utilization and its preoperative drivers is limited. We characterized resource utilization across multiple outcomes and identified clinical and operational drivers of high utilization. Methods We performed a single-center retrospective cohort study of consecutive patients undergoing laparoscopic appendectomy for acute appendicitis (January 2023–December 2024). CA was defined by postoperative pathology (gangrene, perforation, or peri-appendiceal inflammation/abscess; worst-category rule). Primary resource outcomes were length of stay (LOS), total hospitalization cost, operative time, and drain placement. Preoperative predictors included demographics, inflammatory markers (WBC, neutrophil percentage, procalcitonin), bilirubin fractions, fever, symptom-to-surgery interval, admission-to-surgery interval, and shock index. We compared utilization between UA and CA and fit multivariable models for each outcome. Cost was modeled using gamma regression with log link; LOS and operative time using log-linear regression; and drain placement using logistic regression. We additionally modeled high-cost status (≥ P75 and ≥ P90 of costs). Results In the complete-case cohort (n = 1,792), 397 patients (22.15%) had CA. Compared with UA, CA was associated with higher utilization across all outcomes: LOS (median 5.0 vs 4.0 days; p < 0.001), operative time (35.0 vs 30.0 min; p < 0.001), total cost (14,995 vs 14,697 RMB; p = 0.012), and drain placement (35.3% vs 16.3%; p < 0.001) (Table 2). Although median cost differences were modest, the right-skewed cost distribution and concentration of high-cost patients underscore the operational impact; high-cost thresholds were 16,082.7 RMB (P75) and 17,474.9 RMB (P90). In multivariable preoperative models, higher procalcitonin (log-transformed), longer symptom-to-surgery interval, and older age were consistently associated with higher costs and longer LOS. Admission-to-surgery delay and fever were associated with longer LOS. High-cost patients were more likely to be older and to have higher procalcitonin and longer symptom-to-surgery intervals; shock index and fever were additional predictors depending on the threshold (Table 5). Conclusions Resource use in acute appendicitis is multidimensional. CA concentrates utilization, but several potentially modifiable preoperative factors—particularly symptom duration and admission-to-surgery delay—also contribute to high utilization. A multi-outcome, operationally oriented framework may support triage prioritization, operating room scheduling, bed management, and early cost-risk identification in emergency surgical pathways.