Figure 1.

Serum retinol binding protein 4 (RBP4) concentrations in critically ill patients. (a) Serum RBP4 levels are significantly (P < 0.001, Mann-Whitney U test) reduced in critically ill patients (n = 123) as compared to healthy controls (n = 42). (b) No significant differences were detected between ICU patients with sepsis and nonseptic etiology of critical illness. Boxplots are displayed, where the bold line indicates the median per group, the box represents 50% of the values, and horizontal lines show minimum and maximum values of the calculated nonoutlier values; asterisks and open circles indicate outlier values.