ObjectiveTo determine the relationship of hypolipidemia to cytokine concentrations and clinical outcomes in critically ill surgical patients.DesignConsecutive, prospective case series.SettingSurgical intensive care unit of an urban university hospital.PatientsSubjects were 111 patients with a variety of critical illnesses, for whom serum lipid, lipoprotein, and cytokine concentrations were determined within 24 hrs of admission to a surgical intensive care unit. Controls were 32 healthy men and women for whom serum lipid, lipoprotein, and cytokine concentrations were determined.InterventionsBlood samples were drawn on admission to the intensive care unit. Predetermined clinical outcomes including death, infection subsequent to intensive care unit admission, length of intensive care unit stay, and magnitude of organ dysfunction were monitored prospectively.Measurements and Main ResultsMeasurements included total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoproteins A-I and B, phospholipid, triglyceride, interleukin-6, interleukin-10, soluble interleukin-2 receptor, tumor necrosis factor-&agr;, and soluble tumor necrosis factor receptors p55 and p75. Mean serum lipid concentrations were extremely low: total cholesterol, 127 ± 52 mg/dL; low-density lipoprotein cholesterol, 75 ± 41 mg/dL; high-density lipoprotein cholesterol, 29 ± 15 mg/dL. Total, low-density lipoprotein, and high-density lipoprotein cholesterol concentrations and apolipoprotein concentrations inversely correlated with interleukin-6, soluble interleukin-2 receptor, and interleukin-10 concentrations, whereas the triglyceride concentration correlated positively with tumor necrosis factor soluble receptors p55 and p75. Clinical outcomes were related to whether the admission cholesterol concentration was above (n = 56) or below (n = 55) the median concentration of 120 mg/dL. Each of the clinical end points occurred between 1.9- and 3.5-fold more frequently in the very low cholesterol (<120 mg/dL) group. Nine patients (8%) died during the hospitalization. Seven of the nine patients who died had total cholesterol concentrations below the median concentration of 120 mg/dL.ConclusionsLow cholesterol and lipoprotein concentrations found in critically ill surgical patients correlate with interleukin-6, soluble interleukin-2 receptor, and interleukin-10 concentrations and predict clinical outcomes.