Association of Preoperative Prognostic Nutritional Index with Postoperative Outcomes After Emergency Surgery for Strangulated Bowel Obstruction: An Exploratory Retrospective Cohort Study

Abstract Background Strangulated bowel obstruction requires rapid perioperative risk assessment. Prognostic nutritional index (PNI) is calculated from routine blood tests; however, its value in this setting is unclear. We examined its association with postoperative outcomes. Methods In this single-center exploratory retrospective cohort study, we included all 43 consecutive adult patients who underwent emergency surgery for strangulated mechanical bowel obstruction from April 2023 to November 2024. PNI was calculated as 10 × serum albumin (g/dL) + 0.005 × total lymphocyte count (/µL). A receiver operating characteristic (ROC) curve-derived cutoff of 40.7 was used to define the low (≤ 40.7) and high (> 40.7) PNI groups. Complications were limited to in-hospital events of Clavien–Dindo grade II or higher during the index admission. A prespecified multivariable logistic regression model including age, American Society of Anesthesiologists Physical Status (ASA-PS), and PNI group was fitted. Results Overall, 14 patients had low PNI and 29 had high PNI. The ROC area under the curve was 0.675 (95% confidence interval [CI], 0.511–0.839; p = 0.049 vs. 0.5). Complications were more frequent with low PNI (78.6% vs. 34.5%; p = 0.010). In 37 patients with numeric oral-intake data, time to oral intake was longer with low PNI (median, 4.5 vs. 3.0 days; p = 0.041). In a full-cohort sensitivity analysis, 10/14 (71.4%) patients with low-PNI and 27/29 (93.1%) with high-PNI were alive and resumed oral intake during the index admission (p = 0.077). In the full cohort, postoperative stay was also longer (median, 17.5 vs. 11.0 days; p = 0.026). After adjustment for age and ASA-PS, low PNI was associated with higher odds of postoperative complications (adjusted odds ratio, 5.35; 95% CI, 1.05–27.03; p = 0.044), and including PNI improved model fit (Δχ² = 4.52, degree of freedom = 1, p = 0.033). Conclusions Low PNI was associated with overall in-hospital postoperative morbidity and slower in-hospital recovery, but not with any individual complication. PNI may provide a rapid adjunct to emergency preoperative risk assessment; however, its modest discriminatory performance limits standalone use.