How Low Is Too Low? A Retrospective Analysis of Very Low LDL-C Levels in Veterans.

Background: Low-density lipoprotein cholesterol (LDL-C) can build up on the walls of blood vessels, leading to coronary heart disease. Medications used to lower LDL-C levels have demonstrated decreased risks of atherosclerotic cardiovascular disease, but currently, there is no consensus on how to define very low LDL-C levels. It is necessary for the body to have LDL-C to maintain proper brain function; however, the safety and effects of prolonged very low LDL-C levels are unknown. The current study sought to gather information to determine the risks of very low LDL-C levels in a veteran population.

Methods: A retrospective chart review was conducted at a US Department of Veterans Affairs medical center. Patients with hyperlipidemia/dyslipidemia treated with HMG-CoA reductase inhibitors or proprotein convertase subtilisin/kexin type 9 (PCSK9) therapy and LDL-C levels < 40 mg/dL between January 1, 2010, and September 1, 2020, were included. The primary outcome was the rate of intracranial hemorrhage that could be caused by an LDL-C level < 40 mg/dL. The secondary outcomes included actions taken by clinicians, adverse drug reactions (ADRs), duration of therapy, and medication adherence.

Results: This study included 3027 patients. Of the included patients, 8 had an intracranial hemorrhage within 1 year from a documented LDL-C level < 40 mg/dL (0.26%). Thirty-two patients with an LDL-C level < 40 mg/dL did not have a documented ADR with the studied medications. Of the 32 charts, 26 had a clinician address the LDL-C level < 40 mg/dL with either documentation and/or modification of the medication prescribed. The most common ADRs among the studied medications were muscle and joint pain, rash, and cramps. Adherence to the medications was consistently similar for all studied medications.

Conclusions: Of the patient population included in this study, 0.26% of patients had an intracranial hemorrhage within 1 year of having an LDL-C level < 40 mg/dL. The rate of ADRs related to the medications analyzed in this study shows no statistical significance ( > .05). When compared with low- and moderate-intensity statin medications, high-intensity statin medications were statistically significant in resulting in an LDL-C level < 40 mg/dL ( < .001). LDL-C levels < 40 mg/mL were not routinely documented as being addressed in the chart by the clinician.