Prognostic significance of serum albumin level changes in acute ischemic stroke: the role of biological and analytical variation

BACKGROUND: Animal studies have shown a neuroprotective effect of human serum albumin (sAlb) in ischemic stroke (IS). Previous studies have shown an association of high sAlb with better outcome. Our aim is to investigate the kinetics of sAlb in acute IS and its possible correlation with outcome taking into account the analytical and biological variation of sAlb measurement. METHODS: In a prospective observational study, we enrolled 105 patients with acute IS. sAlb was measured upon admission, at 24 h, 48 h, 72 h and Day 7 thereafter. Stroke severity was assessed upon admission and at 72 h, and functional outcome on Day 7. Patients were divided into two groups according to functional outcome on discharge. Calculation of reference change value was used to assess the clinical significance of sAlb changes and multiple logistic regression to assess the independent association between variables and outcome. RESULTS: Fifty-one patients (48.6%) had poor outcome. Their sAlb levels exhibit a significant daily decrease until 72 h (35.9 g/L) compared to baseline (41.1 g/L) and remained low until Day 7 (36.0 g/L). These changes were clinically significant only from 72 h on. Among non-poor outcome patients a significant daily decrease until 72 h (40.9 g/L) was followed by recovery on Day 7 (41.2 g/L), but these changes were not clinically significant. sAlb was not independently associated with the functional outcome at any time-point. CONCLUSIONS: This study shows that sAlb levels might change during the first days after an acute IS, but these changes although statistically significant are not clinically significant if we take into account the analytical and biological variation of sAlb.