Public Release: 

Very low levels of bad cholesterol well-tolerated in heart disease patients

Low cholesterol achieved by PCSK9s does not lead to memory, nervous system impairment

American College of Cardiology

Heart disease patients taking PCSK9 inhibitors to achieve very low levels of cholesterol do not experience an increase in adverse events, including memory impairment or nervous system disorders, but may have an increased risk of cataracts, according to a study today in the Journal of the American College of Cardiology.

Statins are largely used to lower LDL cholesterol, or bad cholesterol, and prevent heart disease. However, some patients need to reduce their LDL cholesterol even further than what they are able to achieve with a maximally tolerated statin or other lipid-lowering therapies. PCSK9 inhibitors can reduce cholesterol by large amounts in high-risk patients, but there have been some concerns on how very low levels of LDL cholesterol effect the body functions reliant on cholesterol.

Researchers in this study pooled data from 14 randomized, controlled studies that included 5,234 patients treated with the PCSK9 alirocumab for up to two years. They looked for the occurrence of adverse events in patients who achieved two or more consecutive LDL cholesterol values of less than 25 mg/dL or less than 15 mg/dL. An LDL level of 25 md/dL was used because it has been suggested to be the level needed for normal cell function.

The overall incidence of adverse events was similar in patients taking alirocumab versus those taking placebo, including musculoskeletal events, neurologic conditions, neurocognitive events (including memory), renal events or liver events. There was not an increased incidence of diabetes, despite previous studies showing an excess of diabetes in patients with LDL cholesterol lower than 30mg/dL on statin therapy.

Analyses did show an increased incidence of cataracts in patients with LDL less than 25 versus greater than 25. This could be a chance finding, or it could be because reducing cholesterol accelerates underlying aging-related changes, contributing to cataracts.

"The safety of these new drugs is critical to patients who have no other means by which to control their life-threatening high cholesterol," said Jennifer Robinson, MD, MPH, lead author of the study and director of the Preventive Intervention Center at the University of Iowa in Iowa City, Iowa. "The long-term effects of very low levels of LDL cholesterol are under evaluation in ongoing large clinical trials."

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The American College of Cardiology is a 52,000-member medical society that is the professional home for the entire cardiovascular care team. The mission of the College is to transform cardiovascular care and to improve heart health. The ACC leads in the formation of health policy, standards and guidelines. The College operates national registries to measure and improve care, offers cardiovascular accreditation to hospitals and institutions, provides professional medical education, disseminates cardiovascular research and bestows credentials upon cardiovascular specialists who meet stringent qualifications. For more, visit acc.org.

The Journal of the American College of Cardiology is the most widely read cardiovascular journal in the world and is the top ranked cardiovascular journal for its scientific impact. JACC is the flagship for a family of journals that publish peer-reviewed research on all aspects of cardiovascular disease. JACC: Cardiovascular Interventions, JACC: Cardiovascular Imaging and JACC: Heart Failure also rank among the top ten cardiovascular journals for impact. JACC: Clinical Electrophysiology and JACC: Basic to Translational Science are the newest journals in the JACC family. Learn more at JACC.org.

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