Low admission LDL-cholesterol is associated with increased 3-year all-cause mortality in patients with non ST segment elevation myocardial infarction

Abstract

Background: The relationship between admission low-density lipoprotein (LDL) levels and long-term outcomes has not been established in patients with acute coronary syndrome. We tested the hypothesis that patients who develop non-ST segment elevation myocardial infarction (NSTEMI) despite low LDL have a worse cardiovascular outcome in the long term.
Methods: Patients admitted with NSTEMI between 1 January 1997 and 31 December 2000 and with fasting lipid profiles measured within 24 hours of admission were selected for analysis. Baseline characteristics and 3-year all-cause mortality were compared between the patients with LDL above and below the median. Multivariate analysis was used to determine the predictors of all-cause mortality, and adjusted survival was analyzed using the Cox proportional hazard model.
Results: Of the total of 517 patients, 264 had LDL £ 105 mg/dL and 253 had LDL > 105 mg/dL. There was no difference in age, gender, severity of coronary artery disease, and left ventricular ejection fraction between the 2 groups. Thirty-six percent of patients with LDL £ 105 mg/dL and 24% of patients with LDL > 105 mg/dL were on lipid-lowering therapy on admission. After 3 years, patients with admission LDL £ 105 mg/dL had higher all-cause mortality rate compared to patients with LDL > 105 mg/dL (14.8% vs. 7.1%, p = 0.005). The higher all-cause mortality persisted (OR 1.8, 95% CI 1.0–3.5, p = 0.05) even after adjustment for confounding variables.
Conclusions: In our cohort, lower LDL-cholesterol at admission was associated with decreased 3-year survival in patients with NSTEMI. Whether this was a result of current therapy or a marker for worse baseline characteristics needs to be studied further.