Frequency of Lp(a) testing and subsequent medication initiation in ASCVD

In a US retrospective real-world study among ASCVD patients, only 0.4% had undergone Lp(a) testing. Regardless of Lp(a) level, Lp(a) testing was associated with more frequent initiation of lipid-lowering therapy.

This summary is based on the publication of Shah NP, Mulder H, Lydon E, et al. - Lipoprotein (a) Testing in Patients With Atherosclerotic Cardiovascular Disease in 5 Large US Health Systems. J Am Heart Assoc. 2024 Nov 5;13(21):e035610. doi: 10.1161/JAHA.124.035610

Introduction and methods

Background

Although increased Lp(a) levels are an independent risk factor for ASCVD [1,2], guideline recommendations on testing for this lipoprotein vary [3-5]. It is unknown how frequently Lp(a) testing is performed in daily clinical practice and in what populations. It is also unclear whether knowledge of a patient’s Lp(a) level changes their clinical management.

Aim of the study

The authors examined the frequency of Lp(a) testing in patients with ASCVD and subpopulations thereof in real‐world clinical practice and the impact of test results on clinical management.

Methods

In a retrospective study, electronic medical record data of 595,684 patients with established ASCVD, an ASCVD event ≤5 years prior to the index date, and ≥2 encounters in the health system ≤2 years before the index date were extracted from 5 large health systems that were part of the CardioHealth Alliance in the US. Patients with a prior Lp(a) test between 2015 and 2018 were excluded. The cohort was divided into 2 groups based on the presence or absence of an Lp(a) test result.

Main results

Frequency of Lp(a) testing: overall and in subpopulations

• There were 2587 patients (0.4%) with a first Lp(a) test result in the period 2019–2021 and 593,097 (99.6%) with no Lp(a) test in the period 2015–2021.
• Multivariable regression analysis demonstrated several factors were independently associated with the likelihood of Lp(a) testing, including diagnosis of coronary artery disease, ischemic stroke/TIA, peripheral artery disease, HF, hyperlipidemia, or familial hypercholesterolemia, prior use of lipid-lowering therapy (LLT), and LDL-c ≥130 mg/dL (all P≤0.03).
• In contrast, older age, Black race, higher BMI, current smoking, hypertension and diabetes were associated with a lower likelihood of Lp(a) testing (all P<0.001).

Effect of Lp(a) testing on medication initiation

• Patients with an Lp(a) test more often received any LLT ≤6 months after the index date, regardless of the Lp(a) level, than those with no Lp(a) test (38.7% vs. 11.2%; P<0.001). They were more frequently started on statin therapy (30.3% vs. 10.6%; P<0.001), ezetimibe (7.6% vs. 0.8%; P<0.001), or a PCSK9 inhibitor (6.7% vs. 0.3%; P<0.001).
• Among patients with elevated Lp(a) levels, the initiation rates of ezetimibe (11.5% vs. 5.9%; P<0.001) and PCSK9 inhibitors (10.9% vs. 4.8%; P<0.001) were higher compared with those with no elevated Lp(a) levels, but there were no differences in the initiation or uptitration of statin therapy (both P>0.05).

Conclusion

This retrospective study on Lp(a) testing and LLT initiation in US clinical practice showed the rate of Lp(a) testing among ASCVD patients was low (0.4%). Older age, Black race, higher BMI, current smoking, and the presence of hypertension or diabetes were independently associated with a lower likelihood of Lp(a) testing. Regardless of Lp(a) level, Lp(a) testing was associated with more frequent initiation of any LLT, including statin therapy, ezetimibe, and PCSK9 inhibitors. Finally, elevated Lp(a) levels were associated with initiation of nonstatin LLT. The authors conclude “there is a critical need for multidisciplinary and inclusive approaches to raise awareness of [Lp(a)] testing and its implications for aggressive preventive management.”

Find this article online at J Am Heart Assoc.

References

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