Association between lipid levels and all-cause and cause-specific mortality in critically ill patients

Extremely low lipid levels are considered a sign of debilitation and illness. The association between lipid levels and the risk of mortality in critically ill patients has not been well investigated. This study was designed to evaluate the association between lipid levels and all-cause and cause-specific mortality in critically ill patients using a large collaborative research database known as the eICU database. In total, 27,316 individuals with low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC) and triglyceride (TG) measurements were analyzed. A J-shaped association was observed between LDL-C, HDL-C, and TC levels and all-cause and noncardiovascular mortality, with low concentrations associated with higher risk. LDL-C, HDL-C and TC levels in the first quintile were associated with higher all-cause and noncardiovascular mortality but not with cardiovascular mortality compared to the reference quintile. There was a marked synergistic effect between low LDL-C combined with low HDL-C on the risk of mortality. Individuals with LDL-C ≤ 96 mg/dL and HDL-C ≤ 27 mg/dL had an increased risk of all-cause mortality (OR 1.52, 95% CI: 1.26–1.82), cardiovascular mortality (OR 1.07, 95% CI: 1.37–1.76) and noncardiovascular mortality (OR 1.82, 95% CI: 1.37–2.43). The results of this observational cohort showed that low LDL-C, HDL-C and TC levels were independently associated with higher all-cause and noncardiovascular mortality in critically ill patients.