Preoperative malnutrition is a risk factor for intraoperative hypotension in high-risk surgical patients: a propensity score-matched cohort study.

BACKGROUND: Intraoperative hypotension (IOH) is associated with adverse outcomes in high-risk surgical patients. Preoperative malnutrition may increase susceptibility to IOH, but evidence regarding its association with IOH assessed through multiple dimensions remains limited. This study aimed to evaluate the association between malnutrition and IOH. METHODS: This retrospective cohort study included 1504 adult patients who underwent elective high-risk non-cardiac surgery under general anesthesia. Nutritional status was assessed using the Global Leadership Initiative on Malnutrition (GLIM) criteria. IOH was evaluated across four dimensions: incidence, cumulative duration, proportion of anesthesia time in IOH, and lowest mean arterial pressure (MAP), based on both absolute (MAP < 65 mmHg) and relative (≥ 20% reduction from baseline) thresholds. The proportion of time in relative IOH, which demonstrated the most clinically meaningful difference, was pre-specified as the primary outcome for multivariable analysis. Associations were examined using propensity score matching and multivariable beta regression analysis. RESULTS: Compared to non-malnourished patients, malnourished individuals had a significantly greater proportion of time in relative IOH (0.48 ± 0.16 vs. 0.39 ± 0.17, Cohen's d = 0.54, P < 0.001), along with longer IOH duration and lower nadir MAP. Absolute IOH metrics showed no significant group differences. Malnutrition remained independently associated with increased relative IOH after adjustment for relevant covariates (P < 0.001). Subgroup and sensitivity analyses confirmed the robustness of these findings. CONCLUSIONS: Preoperative malnutrition is independently associated with increased intraoperative hemodynamic instability when assessed by relative blood pressure thresholds. These findings underscore the importance of incorporating nutritional risk into perioperative risk stratification and highlight the need for prospective studies to validate these associations.