Preoperative immunonutritional status and perioperative outcomes among women undergoing surgery for uterine fibroids: a retrospective cohort study

To evaluate the associations of preoperative prognostic nutritional index (PNI) and systemic immune-inflammation index (SII) with perioperative outcomes in patients undergoing surgery for uterine fibroids. This retrospective cohort study included 9,303 patients who underwent surgery for uterine fibroids. Preoperative PNI and SII were evaluated in relation to intraoperative estimated blood loss (EBL), operative time, and length of hospital stay (LOS). Associations were assessed using continuous and categorized outcomes and restricted cubic spline analyses. After multivariable adjustment, higher SII was associated with greater EBL and longer operative time. Compared with SII ≤ 352.86, SII values of 498.55–716.66 and > 716.66 were associated with higher odds of EBL > 500 mL (OR, 1.65 and 1.81, respectively) and EBL > 200 mL (OR, 1.29 and 1.62, respectively). Higher SII was also associated with operative time > 120 min and > 150 min (OR, 1.28 and 1.42, respectively, for the highest SII category vs. ≤352.86). Restricted cubic spline analyses showed positive nonlinear associations of SII with EBL and operative time. Higher PNI was associated with shorter LOS. Compared with PNI ≤ 48.25, PNI values of 48.25–51.25, 51.25–54.15, and > 54.15 were associated with lower odds of LOS above the median (OR, 0.83, 0.55, and 0.40, respectively) and above the 75th percentile (OR, 0.77, 0.55, and 0.43, respectively). The inverse association between PNI and LOS was consistent across outcome definitions and spline analyses. Preoperative SII was more consistently associated with EBL and operative time, whereas PNI showed the most consistent association with LOS. Although statistically significant associations were observed, some effect sizes were modest and their clinical relevance remains uncertain. PNI and SII may provide additional information on preoperative status, but their clinical utility requires further evaluation and external validation before routine clinical use.