Plasma orexin A does not reflect severity of illness in the intensive care units patients with systemic inflammation

BACKGROUND: Systemic inflammatory response occurs by sepsis and invasive surgery. Recent articles suggest that not only CRP but also procalcitonin, presepsin, and neutrophil gelatinase-associated lipocalin may reflect the severity of systemic inflammation. In addition, as systemic inflammation could degenerate orexin neurons, plasma orexin A might also be a good biomarker to predict the severity. Thus, we have determined relation between plasma biomarker and severity of illness score in patients with systemic inflammation. METHODS: Previous database (UMIN000018427) was used to secondly determine which plasma biomarkers may predict the severity of illness in the ICU patients with systemic inflammation (n = 57, 31 non-sepsis surgical patients and 26 sepsis patients). We measured plasma levels of orexin A, CRP, procalcitonin, presepsin, and neutrophil gelatinase-associated lipocalin were measured, and APACHE II score was assessed in these patients at their admission to the ICU. Data are shown as mean ± SD. Statistical analyses were done with unpaired t test. The correlation between APACHE II score and plasma biomarkers were examined using Pearson’s correlation coefficient and a least squares linear regression line. RESULTS: Demographic data did not differ between sepsis and non-sepsis groups. However, APACHE-II score was significantly higher in sepsis group than those in non-sepsis group (20.9 ± 6.6 vs 15.8 ± 3.2, p < 0.01). There were significant correlations between APACHE II score and plasma CRP (r = 0.532, p < 0.01), procalcitonin (r = 0.551, p < 0.01), presepsin (r = 0.510, p < 0.01), and neutrophil gelatinase-associated lipocalin (r = 0.466, P < 0.01) except orexin A. CONCLUSION: All plasma biomarkers tested except orexin A may reflect the severity of illness in patients with systemic inflammation.