Economic burden of hospital-acquired multidrug-resistant organism infections in patients undergoing gastrointestinal surgery: a bootstrap-based retrospective cohort study.

BACKGROUND: Multidrug-resistant organism (MDRO) infections impose substantial clinical and economic burdens on surgical patients. However, specialty-specific analyses remain limited. This study quantified the economic impact of MDRO hospital-acquired infections (HAIs) on patients undergoing gastrointestinal surgery. METHODS: 100 patients with postoperative HAIs at a tertiary hospital (January 2022-December 2024) were stratified into MDRO (n = 41) and no-MDRO (n = 59) groups. Demographic, surgical, infection data and economic indices were collected via hospital's electronic medical record system, laboratory information system and BlueDragonfly HAI surveillance platform. Statistical analyses were performed using R 4.4.2 software. Based on the analysis of baseline data, significant differences were observed in ICU-related costs, such as Total hospitalization costs, Laboratory diagnostics, Imaging diagnostics, Clinical diagnostic procedures, Nursing care, Disposable therapeutic materials, and Nonsurgical treatments. We hypothesized that prolonged ICU length of stay is associated with increased costs. Considering that the original sample size is relatively small, we adopt the bootstrap resampling method to increase the sample size. A non-parametric bootstrap approach was used to perform probabilistic sensitivity analysis (PSA) to quantify the uncertainty in incremental costs (ΔC) and incremental effects (ΔE). The cost-effectiveness acceptability curve (CEAC) was based on the net monetary benefit (NMB = WTP × ΔE-ΔC), where WTP denotes the willingness-to-pay threshold (in CNY per additional ICU length of stay). RESULTS: The MDRO had significantly longer ICU stay (median 2 vs. 0 days; p < 0.001), durations of antibiotic therapy (median 25 vs. 23 days; p = 0.017) and hospitalization durations (median 35 vs. 29 days; p = 0.030). Treatment outcomes differed significantly between groups (p < 0.05). Total hospitalization costs were substantially higher in the MDRO (median 85,912.86 vs. 64,746.75 CNY; p < 0.05). Incremental cost (ΔC, 95% CI: 18,405-78,031 CNY) and incremental effect (ΔE, 95% CI: 3.09-8.51 days in ICU length of stay) comparing MDRO with no-MDRO. Albeit with notable uncertainty, the 95% confidence ellipse lies essentially in the first quadrant, suggesting that the direction of the cost-effectiveness difference is consistent (higher cost and longer ICU length of stay). WTP thresholds: median ICER (8,376 CNY, 95% CI:5,081-10,864 CNY, probability:39.9%). Significant cost increases, in descending order, were observed for laboratory diagnostics, nonsurgical treatments, clinical diagnostic procedures, nursing care, imaging diagnostics and disposable therapeutic materials (all p < 0.05). CONCLUSION: The study demonstrate that HAIs caused by MDROs in gastrointestinal surgery patients exacerbate medical resource consumption and significantly increase hospitalization costs, prolonging hospital stay duration, ICU length of stay, and duration of antibiotic therapy. Consequently, these infections impose a significant economic burden, with laboratory diagnostics, non-surgical treatments and clinical diagnostic procedures identified as the major cost drivers. We fully acknowledge that, as a retrospective observational study, comparing the MDRO and non-MDRO groups cannot establish that MDRO infection caused the increased costs, without adequate adjustment for confounding factors (e.g., severity of underlying illness, age, length of hospital stay prior to ICU admission).