Early supplemental parenteral nutrition and risk of subsequent enteroatmospheric fistula in high-risk open abdomen patients with persistent enteral nutrition intolerance: a landmark propensity score-matched cohort study

Background High-risk open abdomen (OA) patients with acute gastrointestinal injury (AGI) and persistent enteral nutrition (EN) intolerance are particularly vulnerable to cumulative energy-protein deficit, yet the optimal timing of supplemental parenteral nutrition (SPN) remains uncertain. We evaluated whether earlier SPN initiation was associated with a lower subsequent incidence of enteroatmospheric fistula (EAF) in this population. Methods We conducted a single-center retrospective cohort study of adult OA patients admitted to the intensive care unit between January 2019 and December 2024 who had AGI grade II-III, persistent EN intolerance by ICU Day 3, and a modified Nutrition Risk in the Critically Ill score of at least 5. Using ICU Day 7 as the landmark time point, patients who initiated SPN between ICU Days 3 and 7 were classified as the early-SPN group, and those who initiated SPN after ICU Day 7 as the late-SPN group. Patients who never received SPN were intentionally excluded to focus the analysis on the optimal timing among those who definitively required supplementation. One-to-one propensity score matching was performed. The primary outcome was EAF occurring after ICU Day 7. Results Among 355 screened patients, 284 met the eligibility criteria, including 110 early-SPN and 174 late-SPN patients; 102 matched pairs were analyzed. During ICU Days 3–7, the early-SPN group received higher energy and protein delivery. EAF occurred in 13/102 patients (12.75%) in the early-SPN group and 31/102 (30.39%) in the late-SPN group (relative risk, 0.42; 95% CI, 0.23–0.75; p = 0.002). In an exploratory landmark time-to-event analysis, early SPN was associated with a lower subsequent hazard of EAF (HR, 0.39; 95% CI, 0.21–0.75; log-rank p = 0.003). Mechanical ventilation duration was shorter in the early-SPN group (8.27 ± 10.53 vs. 12.00 ± 13.80 days, p = 0.031), whereas other secondary outcomes were comparable. Conclusion Among high-risk OA patients with AGI and persistent EN intolerance who subsequently required SPN, initiation of SPN between ICU Days 3 and 7 was associated with improved short-term nutritional delivery, shorter mechanical ventilation duration, and a lower subsequent incidence of EAF than later SPN initiation.