# Prescribing Patterns of Evolocumab and Alirocumab in Patients With Familial Hypercholesterolemia: A Cross-Sectional Study Using the National Ambulatory Medical Care Survey, 2018–2019

## TL;DR

This study found that PCSK9 inhibitors like evolocumab and alirocumab are rarely prescribed for FH patients in U.S. outpatient settings, especially among males and minority groups.

## Contribution

The study provides new national data on the low real-world use of PCSK9 inhibitors for FH in the U.S.

## Key findings

- Only 0.3% of FH patient visits resulted in a PCSK9 inhibitor prescription.
- Prescribing was limited to older, white, female patients in primary care settings.
- Each additional year of age increased the odds of PCSK9 inhibitor use by 4%.

## Abstract

Background: Familial hypercholesterolemia (FH) is a hereditary lipid disorder that substantially elevates cardiovascular risk. Despite strong evidence and guideline recommendations, the real-world use of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors in FH remains uncertain.

Objective: This study aimed to evaluate national trends in PCSK9 inhibitor prescribing during ambulatory visits for adults with FH in the United States from 2018 to 2019.

Methods: We conducted a cross-sectional analysis of ambulatory care visits recorded in the 2018-2019 National Ambulatory Medical Care Survey (NAMCS), a nationally representative survey of office-based physicians in the United States. Eligible visits included adults (≥18 years) with a diagnosis of FH (International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) code E78.0). The primary outcome was prescription of a PCSK9 inhibitor (evolocumab or alirocumab), identified through medication codes. Patient demographics, insurance type, and physician specialty were examined. Survey weights were applied to generate national estimates, and logistic regression was used to explore the association between age and prescribing.

Results: Among the weighted total of 20,414,210 visits for adults with FH, only 69,672 visits (0.3%) included a prescription for a PCSK9 inhibitor. Prescribing was observed exclusively among female, White patients and occurred almost entirely in primary care settings. Patients receiving PCSK9 therapy were older than those not prescribed (mean 71.0 vs. 66.5 years, p=0.004). No prescribing was observed among males, racial/ethnic minority groups, or patients seen in surgical or medical specialties. In survey-weighted logistic regression, each additional year of age was associated with a 4% higher odds of PCSK9 prescribing (OR 1.04, 95% CI: 1.02-1.07, p=0.002).

Conclusion: PCSK9 inhibitor use in FH patients during U.S. ambulatory visits was rare, highlighting a persistent gap between evidence-based guidelines and clinical practice. Broader adoption strategies are needed to optimize lipid management and reduce cardiovascular risk in FH.