Fig. 2From: U-shaped association between plasma sphingosine-1-phosphate levels and mortality in patients with chronic systolic heart failure: a prospective cohort studyPlasma S1P levels and quartile grouping. Patients were divided into 4 groups according to the quartiles of baseline plasma S1P levels, and the plasma S1P levels of 54 healthy volunteers in the same area were used as the control group. *indicates P<0.05 in the Mann-Whitney U test when compared with the control group, and # indicates P<0.05 in the Levene test when compared with the control group. The error line is standard deviation. Abbreviations: S1P, sphingosine-1-phosphateBack to article page