Abstract Background Hypoalbuminaemia in patients with MSSA bacteraemia is associated with a delayed time to blood culture sterilization and increased mortality. Although this phenomenon has been postulated to be due to suboptimal antimicrobial exposure, the albumin thresholds that predispose patients to worse outcomes remain unclear. Methods This was a multicentre, retrospective study of adult patients with MSSA-positive blood cultures for at least 48 h despite treatment with in vitro active antimicrobials. To determine the precise cut-off for defining hypoalbuminaemia, we applied a bootstrap resampling approach in combination with Cox proportional hazards models. A range of candidate albumin thresholds was evaluated to identify the optimal value that maximized the partial log-likelihood of the Cox model, with time from target therapy to negative blood cultures as the outcome. Results Among the 461 patients screened, 285 patients met the inclusion criteria; 34% (97/285) were people who inject drugs and 45% (130/285) had definite endocarditis. The median (IQR) albumin level was 2.4 (2–2.9) g/dL. The albumin threshold that corresponded to the highest mean bootstrapped log-likelihood was ≤3.0 g/dL. After propensity score weighting, patients with an albumin level of ≤3.0 g/dL had a significantly slower time to blood culture sterilization compared with patients with albumin levels 3 g/dL (HR = 0.6; 95% CI: 0.44–0.81; P 0.01). Conclusions In the largest study to evaluate the impact of hypoalbuminaemia on the outcomes of patients with MSSA bacteraemia, we identified a cut-off value of albumin ≤3 g/dL to be associated with an increased risk for a delayed blood culture sterilization.
Shah et al. (2025) studied this question.