Lipoprotein(a) testing in clinical practice: real-life data from a large health-care provider

Temporal trends in lipoprotein(a) testing among United States veterans from 2014 to 2023

Objective

Lipoprotein (a) [Lp(a)] is a causal, genetically-inherited risk amplifier for atherosclerotic cardiovascular disease (ASCVD). Practice guidelines increasingly recommend broad Lp(a) screening among various populations to optimize preventive care. Corresponding changes in testing rates and population-level detection of elevated Lp(a) in recent years has not been well described.

Methods

Using Veterans Affairs electronic health record data, we performed a retrospective cohort study evaluating temporal trends in Lp(a) testing and detection of elevated Lp(a) levels (defined as greater than 50 mg/dL) from January 1, 2014 to December 31, 2023 among United States Veterans without prior Lp(a) testing. Testing rates were stratified based on demographic and clinical factors to investigate possible drivers for and disparities in testing: age, sex, race and ethnicity, history of ASCVD, and neighborhood social vulnerability.

Results

Lp(a) testing increased nationally from 1 test per 10,000 eligible Veterans (558 tests) in 2014 to 9 tests per 10,000 (4,440 tests) in 2023, while the proportion of elevated Lp(a) levels remained stable. Factors associated with higher likelihood of Lp(a) testing over time were a history of ASCVD, Asian race, and residing in neighborhoods with less social vulnerability.

Conclusion

Despite a 9-fold increase in Lp(a) testing among US Veterans over the last decade, the overall testing rate remains extremely low. The steady proportion of Veterans with elevated Lp(a) over time supports the clinical utility of testing expansion. Efforts to increase testing, especially among Veterans living in neighborhoods with high social vulnerability, will be important to reduce emerging disparities as novel therapeutics to target Lp(a) become available.

Lipoprotein(a) and the atherosclerotic burden - Should we wait for clinical trial evidence before taking action?

The fact that lipoprotein(a) levels should be regarded as a causal residual risk factor in the atherosclerotic cardiovascular diseases (ASCVD) is now a no-brainer. This review article aims to summarize the latest evidence supporting the causal role of lipoprotein(a) in ASCVD and the potential strategies to reduce the lipoprotein(a) burden until clinical trial results are available. Epidemiological and genetic data demonstrate the causal link between lipoprotein(a) and increased ASCVD risk. That being said, a specific question comes to mind: "must we wait for outcome trials in order to take action?". Given that lipoprotein(a) levels predict incident ASCVD in both primary and secondary prevention contexts, with a linear risk gradient across its distribution, measuring lipoprotein(a) can unequivocally help identify patients who may later benefit from specific lipoprotein(a)-lowering therapies. This understanding has led various National Societies to recommend dosing lipoprotein(a) in high-risk individuals and to support the recommendation of measuring lipoprotein(a) levels at least once in every adult for risk stratification.

Effectiveness of cascade screening for elevated lipoprotein(a), an underdiagnosed family disorder

PURPOSE OF REVIEW

Elevated lipoprotein(a) [Lp(a)] is a prevalent, independent, genetic risk factor for cardiovascular disease. Though crucial for adequate risk assessment, detection of individuals at increased risk because of elevated Lp(a) is severely lacking in practice. In this light, several consensus statements have recommended familial cascade screening strategies to increase detection of elevated Lp(a). This review aims to synthesize findings from recent research into the effectiveness of cascade screening for elevated Lp(a).

RECENT FINDINGS

Cascade screening is an effective method for identifying individuals with elevated Lp(a) and is superior to opportunistic screening. Cascade screening identifies approximately one new case of elevated Lp(a) ≥ 125 nmol/L for every two first-degree relatives screened. The number needed to screen (NNS) ranged from 1.3 to 2.9, depending on Lp(a) threshold values and selected population.

SUMMARY

Cascade screening appears to be a promising strategy for identifying individuals with elevated Lp(a). However, several challenges persist regarding the implementation of this strategy in clinical practice. Deciding on threshold values for initiating cascade screening, considering the implications of ethnicity-related variability of Lp(a) levels, and further research into the clinical relevance of cascade screening are crucial steps. Understanding these factors will be essential for optimizing cascade screening protocols and enhancing its effectiveness in clinical practice.

Lipoprotein(a) Levels in Severe Aortic Stenosis Referred for Transcatheter Aortic Valve Implantation Compared to Controls

Background

Limited observational reports link elevated lipoprotein(a) (Lp[a]) levels to aortic stenosis (AS) or to disease progression. Data on large cohorts of verified severe AS patients are lacking.

Objectives

The purpose of the study was to characterize Lp(a) levels of severe AS patients referred to transcatheter aortic valve implantation (TAVI) and compare them to a large cohort of Lp(a) samples derived from the general population.

Methods

Lp(a) levels obtained from frozen serum samples of TAVI patients between 2012 and 2017 were compared to a control group for whom Lp(a) levels were obtained for any reason and stratified by gender. Multivariable binary logistic regression analyses were conducted to investigate associations between younger age at TAVI and an Lp(a) cutoff of 50 mg/dL.

Results

Lp(a) levels of 503 TAVI were compared to 25,343 controls. Patients in the AS group had mildly higher median Lp(a) levels compared to controls (20.5 vs 18.7 mg/dL, P = 0.04). Lp(a) levels in males with severe AS were higher than controls (19.9 vs 16.6 mg/dL, P = 0.04). Females had a nonsignificant difference (22.1 vs 21.3 mg/dL, P = 0.87). In multivariable analysis, an Lp(a) cutoff of above 50 mg/dL was not associated with an earlier age at TAVI (beta: 1.04; 95% CI: 0.42-2.57; P = 0.94).

Conclusions

Median Lp(a) levels were only mildly higher in severe AS patients undergoing TAVI in comparison to a large control group, mainly driven by higher Lp(a) levels in males. Higher Lp(a) levels were not associated with an earlier age at TAVI, rejecting its association with an accelerated disease progression.

Low prevalence of testing for apolipoprotein B and lipoprotein (a) in the real world

Objective

Apolipoprotein B (ApoB) and lipoprotein (a) (Lp[a]) are predictors of cardiovascular disease (CVD) risk; therefore, current recommendations for CVD risk assessment and management advocate that patients receive testing for ApoB and Lp(a) in addition to the standard lipid panel. However, US guidelines around ApoB and Lp(a) testing have evolved over time and vary slightly by expert committee. The objective of this analysis was to estimate the number of insured individuals in the USA who received any component of a lipid test, or ApoB and/or Lp(a) testing, during 2019.

Methods

We conducted a cross-sectional analysis to estimate the prevalence of any component of a lipid test, ApoB, and/or Lp(a) in the USA using four different claim data sources (including Medicaid, Medicare, and commercially insured enrollees). Prevalence estimates were age-, sex-, payor-, and region-standardized to the 2019 US Annual Social and Economic Supplement of the Current Population Survey. We also described the clinical profile of patients who received lipid testing between 2019 and 2021 (cohort analysis) in Optum claims database. Enrollees were grouped into four non-mutually exclusive cohorts based on their completion of any component of the lipid panel, ApoB, Lp(a), or ApoB and Lp(a).

Results

In the prevalence cohort, over a third (38 %) of insured adults in the USA underwent testing for any component of a lipid panel in 2019. This proportion was higher for individuals aged ≥65 years compared to younger adults (62% vs 31 %). The proportion of ApoB and Lp(a) testing represented only <1 % of testing for any component of a lipid panel. In the cohort analysis, we found that lipid testing increased with age and comorbidities.

Conclusion

These data should be considered by guideline-issuing agencies and organizations to develop education campaigns encouraging more frequent use of tests beyond the standard lipid panel.

Testing practices and clinical management of lipoprotein(a) levels: A 5-year retrospective analysis from the Johns Hopkins Hospital

Objective

Elevated lipoprotein(a) [Lp(a)] is an independent, genetically determined risk factor for atherosclerotic cardiovascular disease (ASCVD). We evaluated the frequency of testing for elevated Lp(a) and subsequent management at the Johns Hopkins Hospital, a large academic medical center, over a 5-year period.

Methods

The Johns Hopkins Hospital (JHH) electronic medical record was queried to identify patients with an encounter between 2017 and 2021, either with established ASCVD or at increased risk, defined as being on any lipid lowering medication or having LDL-C ≥ 190 mg/dL. The frequency of Lp(a) testing and of elevated levels were identified for each year.

Results

Among 111,350 unique adult patients, 2,785 (2.5 %) had at least one Lp(a) test. Patients with Lp(a) testing, compared to those without testing, were younger (mean age 56 years vs. 66 years), more often female (49 % vs. 44 %), Black (24.7 % vs. 24.6 %) or "other" race/ethnicity (12 % vs 10 %), and had higher LDL-C levels (median 118 vs. 91 mg/dL; p < 0.001). The number and frequency of Lp(a) testing increased from 167 (0.57 %) in 2017 to 1155 (5.67 %) in 2021. Lp(a) levels were abnormal in 43.4 % of patients (moderate [75-125 nmol/L]: 10.3 %, high [126-600 nmol/L]: 32.2 %, severe [>600 nmol/L]: 0.9 %). Among 920 patients with high or severe Lp(a) levels, 200 (22 %) had a subsequent referral to cardiology or lipid specialist, and 180 (20 %) had a new lipid-lowering medication prescribed in the subsequent 18 months.

Conclusion

Based on a single-center experience, the frequency of incident Lp(a) testing among increased-risk patients was low but increased significantly over 5-years, likely due to Lipid Clinic referrals with reflex Lp(a) testing and greater awareness about this risk factor. Future work should target appropriate population based Lp(a) testing strategies and clinical decision-making regarding risk management once Lp(a) elevation is diagnosed.

Frequency of lipoprotein(a) testing and its levels in Pakistani population

BACKGROUND

Lipoprotein(a) [Lp(a)] is a highly atherogenic particle identified as an independent risk factor for the development of atherosclerotic cardiovascular disease (ASCVD). This study aimed to investigate the frequency of Lp(a) testing and the incidence of elevated Lp(a) levels in the Pakistani population.

METHODS

For this observational study, Lp(a) and lipid profile data from five years (June 2015 to October 2020) were acquired from the electronic patient records of a diagnostic laboratory with a countrywide network. The association of age and total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), non-HDL, and triglyceride (TG) levels with two thresholds for Lp(a), that is, <30 mg/dL and ≥30 mg/dL, was calculated using the Kruskal-Wallis test, while the association between Lp(a) levels and lipid variables was calculated using Spearman correlation.

RESULTS

For five years, 1060 tests were conducted, averaging 212 tests per year. Of these, 37.2% showed Lp(a) levels above 30 mg/dL. No significant differences were observed in the results between males and females. However, younger individuals displayed significantly higher Lp(a) levels. Additionally, there was only a weak correlation between the Lp(a) levels and other lipid variables.

CONCLUSION

Despite being recognized as a risk factor for ASCVD in the Pakistani population, only a small proportion of the large population underwent Lp(a) testing. Moreover, a significant proportion of the population exceeded this threshold.

Trends and findings of lipoprotein(a) testing and associated cardiovascular disease profiles: a large single-center study from the Middle East-Gulf region

Background

Lipoprotein(a) [Lp(a)] is a genetically determined risk factor for atherosclerotic cardiovascular disease (CVD). Limited data are available on Lp(a) testing from the Middle-East region. Therefore, we aim to evaluate the utilization and yield of Lp(a) testing over time and characterize CVD profiles of patients with abnormal Lp(a) tasting at a single-quaternary-care center in the United Arab Emirates.

Methods

Unique Lp(a) tests conducted between 07/2017 and 10-2023 were included. Overtime trends in Lp(a) test utilization and abnormal Lp(a) [defined as Lp(a) > 125 nmol/L] test findings were described. CVD rates in patients with abnormal Lp(a) were compared to those with Lp(a) ≤ 125 nmol/L using appropriate methods.

Results

In our center, 0.95% of the patients (n = 5,677) had their Lp(a) measured, with a median level of 32 [11-82] nmol/L. Lp(a) was abnormal in 15.9% of the tests. Over the years 2018-2022, there was a 109% increase in Lp(a) testing, with concomitant up-trends in findings of abnormal Lp(a) (11.8% to 16.4%, P = 0.02). Compared to patients with Lp(a) ≤ 125 nmol/I, those with abnormal Lp(a) had higher rates of any prevalent CVD (34% vs. 25.1%, P < 0.001), CAD (25.6% vs. 17.7%, P < 0.001), HF (6.5% vs. 3.8%, P < 0.001), and stroke (7.1% vs. 4.4%, P < 0.001).

Conclusion

Almost one in six patients tested for Lp(a) had abnormally elevated Lp(a), and CVD was prevalent in one-third of the patients who tested abnormal for Lp(a). The study highlights the growing awareness of the relevance of Lp(a) for CVD risk stratification and prevention.

Elevated Lp(a): Guidance for Identifying and Managing Patients

Lipoprotein(a) (Lp(a)) is a unique low-density lipoprotein-like lipoprotein that is considered an independent and causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valve stenosis. The Lp(a) molecule also contains apolipoprotein A and apolipoprotein B, which collectively promote atherosclerosis, thrombosis, and inflammation. Lp(a) is highly genetic and minimally responsive to nonpharmacological measures. Lp(a) serum levels ≥125 nmol/L are associated with increased ASCVD risk, but this threshold has not been accepted universally. Elevated Lp(a) is the most common genetic dyslipidemia affecting approximately 20% of the general population. Certain currently available lipid-lowering drugs, including the proprotein convertase subtilisin/kexin type 9 therapies, produce moderate reductions in Lp(a); however, none are indicated for the treatment of elevated Lp(a). There are currently four investigational RNA-based therapeutic agents that reduce Lp(a) by 70% to 100%. Two of these agents are being evaluated for ASCVD risk reduction in adequately powered outcomes trials, with results expected in 2 to 3 years. Until such therapies become available and demonstrate favorable clinical outcomes, strategies for elevated Lp(a) primarily involve early and intensive ASCVD risk factor management.

Concordance of a High Lipoprotein(a) Concentration Among Relatives

Importance

Lipoprotein(a) (Lp[a]) concentrations are a highly heritable and potential causal risk factor for atherosclerotic cardiovascular disease (ASCVD). Recent consensus statements by the European Atherosclerosis Society and American Heart Association recommend screening of relatives of individuals with high Lp(a) concentrations, but the expected yield of this approach has not been quantified in large populations.

Objective

To measure the prevalence of high Lp(a) concentrations among first- and second-degree relatives of individuals with high Lp(a) concentrations compared with unrelated participants.

Design, Setting, and Participants

In this cross-sectional analysis, pairs of first-degree (n = 19 899) and second-degree (n = 9715) relatives with measured Lp(a) levels from the UK Biobank study and random pairs of unrelated individuals (n = 184 764) were compared. Data for this study were collected from March 2006 to August 2010 and analyzed from December 2021 to August 2023.

Exposure

Serum Lp(a) levels, with a high Lp(a) level defined as at least 125 nmol/L.

Main Outcome and Measure

Concordance of clinically relevant high Lp(a) levels in first- and second-degree relatives of index participants with high Lp(a) levels.

Results

A total of 52 418 participants were included in the analysis (mean [SD] age, 57.3 [8.0] years; 29 825 [56.9%] women). Levels of Lp(a) were correlated among pairs of first-degree (Spearman ρ = 0.45; P < .001) and second-degree (Spearman ρ = 0.22; P < .001) relatives. A total of 1607 of 3420 (47.0% [95% CI, 45.3%-48.7%]) first-degree and 514 of 1614 (31.8% [95% CI, 29.6%-34.2%]) second-degree relatives of index participants with high Lp(a) levels also had elevated concentrations compared with 4974 of 30 258 (16.4% [95% CI, 16.0%-16.9%]) pairs of unrelated individuals. The concordance in high Lp(a) levels was generally consistent among subgroups (eg, those with prior ASCVD, postmenopausal women, and statin users). The odds ratios for relatives to have high Lp(a) levels if their index relative had a high Lp(a) level compared with those whose index relatives did not have high Lp(a) levels were 7.4 (95% CI, 6.8-8.1) for first-degree relatives and 3.0 (95% CI, 2.7-3.4) for second-degree relatives.

Conclusions and Relevance

The findings of this cross-sectional study suggest that the yield of cascade screening of first-degree relatives of individuals with high Lp(a) levels is over 40%. These findings support recent recommendations to use this approach to identify additional individuals at ASCVD risk based on Lp(a) concentrations.

Prevalence of lipoprotein(a) measurement in patients with or at risk of cardiovascular disease

INTRODUCTION

Lipoprotein(a) [Lp(a)] is a genetically determined independent risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valve disease. Despite recommendations from professional societies in the cardiovascular field, the awareness of elevated Lp(a) as a risk factor and screening for Lp(a) are suspected to be low.

METHODS

We conducted a retrospective, observational case control study of patient charts from January 1, 2017 to June 19, 2022. The primary aims were 1) to describe the proportion of patients at the healthcare network's primary care and cardiology clinics that met Lp(a) screening criteria and were tested; and 2) to describe the proportion of patients throughout the entire healthcare network that had Lp(a) measured.

RESULTS

Of the 2,412,020 patient charts in the health network, only 5,942 (0.25 %) had Lp(a) measured. Of the 84,581 patients in primary care or cardiology clinics who met screening criteria, only 1,311 (1.55 %) had Lp(a) measured. Patients with Lp(a) measured were more likely to be younger, non-Hispanic/Latinx, had a lipid panel measured, a cardiac computed tomography (CT) imaging study, and higher low-density lipoprotein-cholesterol. Patients with ASCVD, heart failure, ischemic heart disease, aortic stenosis, peripheral vascular disease, or a stroke did not feature highly among patients who received Lp(a) testing. Having an abnormal or risk-enhancing Lp(a) level was associated with being female and/or being Black/African American.

CONCLUSIONS

Despite increased awareness of Lp(a) and its contribution to cardiovascular disease there exists a paucity of testing. Increased Lp(a) testing can identify patients who have an increased cardiovascular risk underestimated by other metrics.

Lipoprotein(a) Testing Trends in a Large Academic Health System in the United States

Background Despite its high prevalence and clinical significance, clinical measurement of lipoprotein(a) is rare but has not been systematically quantified. We assessed the prevalence of lipoprotein(a) testing overall, in those with various cardiovascular disease (CVD) conditions and in those undergoing cardiac testing across 6 academic medical centers associated with the University of California, in total and by year from 2012 to 2021. Methods and Results In this observational study, data from the University of California Health Data Warehouse on the number of individuals with unique lipoprotein(a) testing, unique CVD diagnoses (using International Classification of Diseases, Tenth Revision [ICD-10], codes), and other unique cardiac testing were collected. The proportion of total individuals, the proportion of individuals with a given CVD diagnosis, and the proportion of individuals with a given cardiac test and lipoprotein(a) testing any time during the study period were calculated. From 2012 to 2021, there were 5 553 654 unique adults evaluated in the University of California health system, of whom 18 972 (0.3%) had lipoprotein(a) testing. In general, those with lipoprotein(a) testing were more likely to be older, men, and White race, with a greater burden of CVD. Lipoprotein(a) testing was performed in 6469 individuals with ischemic heart disease (2.9%), 836 with aortic stenosis (3.1%), 4623 with family history of CVD (3.3%), 1202 with stroke (1.7%), and 612 with coronary artery calcification (6.1%). For most conditions, the prevalence of testing in the same year as the diagnosis of CVD was relatively stable, with a small upward trend over time. Lipoprotein(a) testing was performed in 10 753 individuals (1.8%) who had lipid panels, with higher rates with more specialized testing, including coronary computed tomography angiography (6.8%) and apolipoprotein B (63.0%). Conclusions Lipoprotein(a) testing persists at low rates, even among those with diagnosed CVD, and remained relatively stable over the study period.

Extreme lipoprotein(a) in clinical practice: A cross sectional study

Introduction

Measurement of lipoprotein(a) [Lp(a)] is recommended once in a lifetime to identify individuals at high risk of atherosclerotic cardiovascular disease (ASCVD). We aimed to analyze the clinical features of patients with extreme Lp(a).

Methods

Cross-sectional, case-control study of a single healthcare organization between 2015 and 2021. Individuals with extreme Lp(a) > 430 nmol/L (53 of 3900 tested patients) were compared to age- and sex-matched controls with normal range Lp(a).

Results

Mean patient age was 58 ± 14 years (49% women). Myocardial infarction (47.2% vs. 18.9%), coronary artery disease (CAD) (62.3% vs. 28.3%), and peripheral artery disease (PAD) or stroke (22.6% vs. 11.3%) were more prevalent in patients with extreme than normal range Lp(a). The adjusted odds ratio [95% confidence interval (CI)] associated with extreme compared to normal range Lp(a) was 2.50 (1.20-5.21) for myocardial infarction, 2.20 (1.20-4.05) for CAD, and 2.75 (0.88-8.64) for PAD or stroke. A high-intensity statin plus ezetimibe combination was issued by 33% and 20% of CAD patients with extreme and normal range Lp(a), respectively. In patients with CAD, low density lipoprotein cholesterol (LDL-C) <55 mg/dL was achieved in 36% of those with extreme Lp(a) and 47% of those with normal range Lp(a).

Conclusions

Extremely elevated Lp(a) levels are associated with an approximately 2.5-fold increased risk of ASCVD compared with normal range Lp(a) levels. Although lipid-lowering treatment is more intense in CAD patients with extreme Lp(a), combination therapies are underused, and attainment rates of LDL-C goals are suboptimal.