Effects of enteral nutrition strategies on clinical outcomes in critically ill patients with shock: a systematic review and meta-analysis

Objective Shock is a life-threatening clinical emergency that demands a sound treatment strategy. Nutritional support is among the key adjuvant therapies, but its application in shock remains controversial. This study explores how early enteral nutrition (EEN) affects the outcome of critically ill patients admitted with shock. Methods This meta-analysis searched PubMed, the Cochrane Library, EMBASE, and China National Knowledge Infrastructure (CNKI) over a period from the inception of each database to October 31, 2025. Critically ill patients admitted with shock were included as the study cohort. The primary outcomes were 28-day mortality and 90-day mortality. Secondary outcomes included ICU mortality, ICU length of stay (LOS-ICU), in-hospital mortality, hospital length of stay (LOS-H), ventilator-free days (VFD), nosocomial infection/reinfection, and adverse complications. Results Thirteen trials were included in this study. For the primary outcomes, EEN was not associated with 28-day mortality [relative risk (RR) = 1.03, 95% CI: 0.93–1.14] and 90-day mortality (RR = 1.04, 95% CI: 0.95–1.14). For secondary outcomes, EEN decreased LOS-ICU [standardized mean difference (SMD) = −0.28, 95% confidence interval (CI): −0.53 to −0.03] and LOS-H (SMD = −0.41, 95% CI: −0.61 to −0.21), without affecting VFD, nosocomial infection or reinfection, and Adverse reactions or complications. Exploratory subgroup analyses suggested that the benefits of EEN varied by nutritional regimen. The high initial protein group was linked to lower LOS-ICU (SMD = −0.94, 95% CI: −1.59 to −0.30). The high initial calorie group was associated with shorter LOS-H (SMD = −0.12, 95% CI: −0.20 to −0.04), whereas the low initial calorie group reduced the adverse reactions or complications (RR = 0.44, 95% CI: 0.25 to 0.77). Conclusion In critically ill patients with shock, EEN with high initial caloric or protein supply may reduce hospital stay, whereas low initial caloric early enteral nutrition is associated with fewer adverse reactions. Given post-hoc subgroup limitations and marked population heterogeneity, findings should be interpreted cautiously. Additional high-quality trials are needed to develop individualized nutritional strategies for these patients. Systematic Review Registration : identifier CRD420261282657.