Association of hypoalbuminemia and timely albumin infusion with clinical outcomes in patients with sepsis: a retrospective cohort study.

Background: Hypoalbuminemia is frequently observed in patients with sepsis. However, its prognostic significance and the association between the timing of albumin administration and clinical outcomes remain uncertain. This study aimed to investigate the association of hypoalbuminemia and timely albumin infusion with clinical outcomes in patients with sepsis. Methods: This retrospective cohort study included adult patients with sepsis admitted to the hospital. Baseline serum albumin was defined as the lowest albumin level measured within 24 h after admission or sepsis diagnosis. Hypoalbuminemia was defined as serum albumin < 30 g/L. Among patients with hypoalbuminemia, timely albumin infusion was defined as documented albumin administration initiated within 24 h after the first serum albumin level < 30 g/L. The available data captured only the presence and timing of administration, not albumin concentration, dose, duration, or cumulative exposure. The primary outcome was in-hospital mortality. Multivariable logistic regression was used to assess the association between hypoalbuminemia and mortality and, separately, the exploratory association between timely albumin infusion and mortality. Results: A total of 628 patients with sepsis were included, of whom 296 had hypoalbuminemia and 332 did not. Patients with hypoalbuminemia had higher disease severity scores, higher lactate levels, and a greater need for mechanical ventilation, vasoactive drugs, renal replacement therapy, and intensive care unit admission. Compared with the non-hypoalbuminemia group, the hypoalbuminemia group had significantly higher in-hospital mortality (30.1% vs. 17.8%, Conclusions: Hypoalbuminemia was associated with greater disease severity and worse clinical outcomes in patients with sepsis, supporting its role as a prognostic marker. The observed association between timely albumin infusion and lower mortality was exploratory and may be partly explained by residual confounding, treatment-selection bias, and immortal time or survival bias. These findings do not establish a survival benefit or support a therapeutic recommendation for albumin infusion. Prospective studies with detailed time-stamped exposure data and standardized treatment information are required.