The Systemic Inflammatory Response Syndrome (SIRS) in acutely hospitalised medical patients: a cohort study

Background: Sepsis is an infection which has evoked a systemic inflammatory response. Clinically, the Systemic Inflammatory Response Syndrome (SIRS) is identified by two or more symptoms including fever or hypothermia, tachycardia, tachypnoea and change in blood leucocyte count. The relationship between SIRS symptoms and morbidity and mortality in medical emergency ward patients is unknown. Methods: We conducted a prospective cohort study of the frequency of SIRS and its relationship to sepsis and death among acutely hospitalised medical patients. In 437 consecutive patients, SIRS status, blood pressure, infection and comorbidity on admission was registered together with 28day mortality. Results: A hundred and fifty-four patients (35%) had SIRS on admission, 211 patients (48%) had no SIRS, and 72 patients (16%) had insufficient data to evaluate their SIRS status. SIRS patients were 2.2 times more frequently infected, with 66/154 SIRS patients versus 41/211 non-SIRS patients: p < 0.001, relative risk (RR) 2.2 (95% confidence interval (CI) 1.6-3.1), and they had a 6.9 times higher 28-day mortality than non-SIRS patients with 15/154 SIRS patients versus 3/211 non-SIRS patients: p = 0.001, RR 6.9 (95% CI 2.0-23.3). Most of the deaths among patients with SIRS occurred among patients with malignant conditions. Septic shock developed in 4/154 (3%) of the patients with SIRS, whereas this occurred in only one of the 211 patients (0.5%) without SIRS on arrival: p = 0.08, RR 5.5 (95% CI 0.6-48.6). Conclusion: We found SIRS status on admission to be moderately associated with infection and strongly related to 28-day mortality.