Measuring Serum Amyloid A for Infection Prediction in Aneurysmal Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage
(aSAH) is associated with high
rates of mortality and morbidity. Nosocomial infections, such as pneumonia
or urinary tract infections, are among the main causes of worsening
outcomes and death. The aim of this study was to discover a biomarker
to predict infection in aSAH patients. For this purpose, the plasma
of infected and noninfected patients was compared using quantitative
mass spectrometry. The most interesting differentially expressed proteins
were selected for validation by immunoassays on plasma samples taken
from patients (n = 81) over 10 days of hospitalization.
Predictive performances were established using Mann–Whitney
U tests and receiver operating characteristic curves. Quantitative
proteomics identified 17 significantly regulated proteins. Of these,
levels of serum amyloid A (SAA) were significantly higher in infected
patients (p < 0.007). ELISA confirmed that the
concentrations were significantly higher (p <
0.002) already at hospital admission in patients who subsequently
developed an infection during their hospitalization, (AUC of 76%)
for a cutoff value of 90.9 μg/mL. Our data suggested that measuring
SAA could be an efficient means of detecting patients susceptible
of developing an infection during hospitalization after an aSAH. Its
predictive capacity could lead to earlier antibiotherapy, improved
patient management, and potentially better long-term outcomes.