Fig. 1

Panel a. Blood interleukin-6 (IL-6) levels on emergency department arrival. The patients who were discharged alive from the intensive care unit within 7 days had lower blood IL-6 levels than the patients who did not survive (P < 0.0001). Error bars indicate the standard error of the mean. P values were calculated by using the Mann–Whitney U test. Panel b. Receiver-operating characteristic curve analysis. The area under the curve of the receiver-operating characteristic curves of the blood IL-6 levels was 0.76 for prolonged ICU stay (95 % confidence interval [CI], 0.67–0.84; P < 0.0001) and 0.76 for 28-day mortality (95 % CI, 0.50–1.02; P = 0.021)