Serum Soluble Triggering Receptor Expressed on Myeloid Cells-1 in Acute Respiratory Distress Syndrome: A Prospective Observational Cohort Study

Background/PurposeSerum soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), a detector of acute inflammatory response to microbial products and a good marker for diagnosing sepsis and pneumonia, has not yet been described as a predictor for infection or a prognostic factor in patients with acute respiratory distress syndrome (ARDS).MethodsThis prospective observational cohort study enrolled 63 ventilated adult patients with ARDS; 50 as septic and 13 as non-septic, and followed them for 28 days in intensive care units at a university hospital in Taiwan. Serial serum sTREM-1 levels and cytokines, such as interleukin (IL)-1, IL-8, and tumor necrosis factor-α, on days 1, 3, 5, 7 and 14 were measured by an enzyme-linked immunosorbent assay. The association between biomarkers and clinical infectious diagnosis/outcome in ARDS was explored.ResultsSerum sTREM-1 and cytokine levels could not differentiate septic from non-septic ARDS. Serum log sTREM-1 and inflammatory cytokine levels were correlated positively (r = 0.325 for IL-1β; r = 0.247 for IL-8; r = 0.480 for tumor necrosis factor-α). As prognostic factors, higher serum sTREM-1 level on day 1 and increasing levels over time, especially in the first 5 days, were independent predictors of mortality on day 28, using a multivariate Cox regression model. Serum sTREM-1 levels remained stable or even increased in the non-surviving patients, but decreased in the survivors.ConclusionSerum sTREM-1 level might not be a reliable marker for infection in ARDS patients. However, as an inflammatory marker, initial serum sTREM-1 level and its trend over time, especially in the first 5 days, could be predictive of short-term mortality. A progressive decline in serum sTREM-1 levels during follow-up indicates a favorable outcome, whereas persistently elevated sTREM-1 indicates a poor prognosis and should lead to a re-evaluation of therapy