Serum uric acid level as a prognostic marker in patients with acute respiratory distress syndrome

Abstract

Purpose: Uric acid acts as both a pathogenic inflammatory mediator and an antioxidative agent. Several studies have shown that uric acid level correlates with the incidence, severity, and prognosis of pulmonary diseases. However, the association between uric acid level and acute respiratory distress syndrome (ARDS) has not been studied. This study was conducted to elucidate how serum uric acid level is related with clinical prognosis of ARDS. Methods: A retrospective cohort study with propensity score matching was conducted at a medical intensive care unit of a tertiary teaching hospital. The medical records of patients diagnosed with ARDS admitted from 2005 through 2011 were reviewed. Results: Two hundred thirty-seven patients with ARDS met the inclusion criteria. Patients with a serum uric acid level <3.0 mg/dL were classified into the low uric acid group, and those with a level >= 3 mg/dL were classified into the normal to high uric acid group. We selected 40 patients in each group using propensity score matching. A higher percentage of patients in the low uric acid group experienced clinical improvement in ARDS. More patients died from sepsis in the normal to high uric acid group. Kaplan-Meier analysis showed that a low serum uric acid level was significantly associated with better survival rate. Conclusion: In patients with ARDS, a low serum uric acid level may be a prognostic marker of a low risk of in-hospital mortality.