Nutritional status-based model for predicting low-lactate shock: A retrospective cohort study

Background: Although Sepsis-3.0 defines septic shock as hypotension with serum lactate levels >2.0 mmol/L, this criterion may miss low-lactate shock: a clinically significant phenotype characterized by hypotension but without elevated lactate levels. The epidemiological characteristics and prognostic significance of low-lactate shock remain unclear, highlighting a critical gap in current shock management models. Methods: We conducted a retrospective cohort study of 3,134 patients with shock admitted to a tertiary care medical institution from January 2015 to March 2022. We used propensity score matching (1:2 ratio) to control for confounding factors, aiming to determine the prevalence of low-lactate shock (lactate ≤ 2.0 mmol/L), identify risk factors through multivariable logistic regression, and validate the predictive model (NRS-APACHE II-TG-TBIL) using ROC analysis. Results: The 28-day mortality rate was slightly lower in the low-lactate shock group compared to the high-lactate group (25.4% [94/369] vs. 35.8% [990/2,765], respectively). The age, nutritional risk screening (NRS-2002) score, and venous thromboembolism (VTE) risk score were significantly lower in the low-lactate shock group than in the high-lactate shock group ( P < 0.05). No statistically significant differences were observed in gender distribution ( P = 0.092). Multivariable analysis identified four independent predictors of low-lactate shock: NRS-2002 (OR=0.570, P <0.001), APACHE II (OR=0.869, P <0.001), TG (OR=0.772, P =0.035), and TBIL (OR=0.993, P =0.002). The composite NRS-APACHE II-TG-TBIL model showed excellent discrimination (AUC=0.800, P <0.001) with balanced sensitivity (72.6%) and specificity (73.5%). Conclusions: Low-lactate shock carries substantial mortality risk (25.4%). The validated NRS-APACHE II-TG-TBIL model (AUC=0.800) provides an effective tool for early detection, addressing critical diagnostic gaps in shock management.