Lower serum lipid levels are related to respiratory impairment in patients with ALS

Abstract

Background: Recently hyperlipidemia was reported to be related to a significantly better outcome in amyotrophic lateral sclerosis (ALS). To investigate this, we evaluated the status of blood lipids in a large Italian series of patients with ALS, and assessed the effect of hyperlipidemia on patients' survival.

Methods: The study population included 658 patients with ALS consecutively observed in 2 Italian ALS centers between 2000 and 2006. They were compared to a series of 658 healthy subjects, matched by age and gender.

Results: The mean levels of total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), and the LDL/HDL ratio were similar in patients with ALS and controls. Total cholesterol, HDL, triglyceride, and LDL/HDL ratio levels showed a significant decrease in patients with forced vital capacity <70% compared to those with FVC >or=90%. For each level of ALS-FRS, poorer respiratory function was related to a lower LDL/HDL ratio. Univariate survival analysis did not find any significant effect of LDL/HDL ratio on survival, either when comparing patients with ratios <or=2.99 vs >2.99 or patients in the first quartile of LDL/HDL ratio (<or=1.67) vs those in the fourth quartile (>2.79). No dose-response was found for LDL/HDL ratio subdividing patients into 5 quintiles.

Conclusion: Our findings do not support the observation that patients with amyotrophic lateral sclerosis have hyperlipidemia or that hyperlipidemia in this population is related to longer survival. However, some evidence emerged that respiratory impairment, but not a worse clinical status or a lower body mass index, is related to a decrease in blood lipids and LDL/HDL ratio.