Low levels of LDL cholesterol associated with a 65% increased risk of death in heart attack patients

This study was published in Critical Care Medicine 2015 Jun;43(6):1255-64

Study title and authors:
Lipid paradox in acute myocardial infarction-the association with 30-day in-hospital mortality.

Cheng KH, Chu CS, Lin TH, Lee KT, Sheu SH, Lai WT.
Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/25738856

The Killip classification (four classes - I to IV) is a system used in individuals with a heart attack. Individuals with a low Killip class are less likely to die within the first 30 days after their heart attack than individuals with a high Killip class.

This study was designed to clarify the relationship between cholesterol levels, Killip classification, and 30-day mortality in patients with a heart attack. The study included 724 heart attack patients.

The study found:
(a) Low-density lipoprotein (LDL) cholesterol and triglyceride levels were significantly lower in high-Killip (III + IV) patients compared with low-Killip (I + II) patients.
(b) Patients with low-density lipoprotein (LDL) cholesterol less than 62.5 mg/dL (1.6 mmol/L) had a 65% increased risk of death compared with patients with patients with low-density lipoprotein (LDL) cholesterol more than 62.5 mg/dL (1.6 mmol/L).
(c) Patients with triglyceride levels less than 110 mg/dL (1.24 mmol/L) had a 405% increased risk of death compared with patients with patients with triglyceride levels more than 110 mg/dL (1.24 mmol/L).
(d) Patients with a high-Killip classification and with with triglycerides less than 62.5 mg/dL (1.6 mmol/L) and low-density lipoprotein (LDL) cholesterol less than 110 mg/dL (1.24 mmol/L) had a 10.9-fold higher risk of death than patients with a low-Killip classification with triglycerides greater than 62.5 mg/dL (1.6 mmol/L) and low-density lipoprotein (LDL) cholesterol greater than 110 mg/dL (1.24 mmol/L).

Cheng concluded: "Low low-density lipoprotein (LDL) cholesterol, low triglycerides, and high Killip severity were associated with significantly higher 30-day in-hospital mortality in patients presenting with acute myocardial infarction".