Prognostic value of the biomarkers serum amyloid A and nitric oxide in patients with sepsis

Abstract

Objective: Sepsis is a major cause of mortality among critically ill patients in the intensive care unit (ICU). Alterations in serum amyloid A (SAA) and nitric oxide (NO) levels have been associated with mortality in critically ill patients. In the present study, we investigated the predictive value of SAA and/or NO compared to traditional predictive markers such as C-reactive protein (CRP) and Acute Physiology and Chronic Health Evaluation II (APACHE II) score.

Methods: 100 adult patients with sepsis and 25 without sepsis were enrolled in a prospective, randomized study in our ICU. The APACHE II score was calculated, and their peripheral venous blood SAA, NO and CRP levels were evaluated on days 1, 3, and 7 after sepsis was diagnosed. The patients were sorted based on incidence of septic shock into septic shock (A) and non-septic shock (B) groups. Comparative analyses of altered levels of these indicators between the two groups were performed, and correlations between SAA, NO, and the more traditional APACHE II score were probed. Patients were sorted based on survival status into death (D) and survival (S) groups based on death endpoint within 28 days after admission.

Results: We observed that the difference in APACHE II score, SAA and CRP levels were statistically significantly (p < 0.05) between groups A and B on days 1, 3 and 7 post-diagnosis, while inter-group NO level significantly differed (p < 0.05) on days 1 and 3 post-diagnosis, no apparent difference was observed on day 7 post-diagnosis. For groups D and S, SAA, CRP and NO levels significantly differed (p < 0.05) on days 3 and 7 post-diagnosis, with no apparent difference on day 1. APACHE II score was significantly different on day 7 (p < 0.05), however the difference on days 1 and 3 were non-significant. We also demonstrated a positive correlation between APACHE II scores, SAA levels on days 1, 3, and 7, as well as NO levels on days 1 and 3. In addition, for the D and S groups, SAA at all time points, NO on day 3 and CRP on day 7 positively correlated with increased death events.

Conclusion: The dynamic monitoring of SAA and NO serum levels with APACHE II scores better reflect the severity of sepsis than traditional indicators like CRP and may serve as independent prognosticators of sepsis in critically ill patients, shorten time to diagnosis confirmation and improve therapeutic decision-making.

Keywords: APACHE II score; CRP; Mortality; Sepsis; Septic shock; Serum amyloid A nitric oxide.