Impact of Hypoalbuminemia on Clinical Outcomes in Patients Receiving Cefazolin for Methicillin-Susceptible Staphylococcus aureus Bacteremia

Background: Cefazolin is a preferred treatment option for methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. Recent studies have suggested a potential impact on clinical outcomes in patients with hypoalbuminemia treated with highly protein-bound antimicrobials. Objective: The purpose of this study was to determine if there are any differences in clinical outcomes between normoalbuminemic and hypoalbuminemic patients treated with cefazolin for bacteremia. Methods: A retrospective, multicentered cohort study of patients hospitalized between 2019 and 2023 with MSSA bacteremia treated with cefazolin for at least 24 hours prior to culture clearance. Patients were divided into hypoalbuminemia (serum albumin ≤2.5 mg/dL) or normoalbuminemia groups. The primary outcome was time to culture clearance. Results: Of 69 patients included (50 in normoalbuminemia group and 19 in hypoalbuminemia group), the most common sources of bacteremia were line-related, osteoarticular, and infective endocarditis. Deep-seated infections were present in 24% of the normoalbuminemia group and 58% of the hypoalbuminemia group. Patients with hypoalbuminemia had a significantly longer mean hospital length of stay (12 vs 7 days, P = 0.016). After adjusting for deep-seated infection, hypoalbuminemia was associated with increased time to culture clearance by 1.2 days ( P = 0.039). In-hospital mortality was significantly higher in the hypoalbuminemia group (26% vs 4%, P = 0.015). Conclusion and Relevance: Limited research is available describing the relationship between serum albumin levels and clinical outcomes. Our study suggests patients with hypoalbuminemia treated with cefazolin for MSSA bacteremia have significantly longer time to culture clearance, increased mortality, and longer length of stay.