Higher Lipoprotein(a) Level Linked to Long-Term ASCVD Risk

An increased lipoprotein(a) level is associated with incident atherosclerotic cardiovascular disease (ASCVD) in middle-aged individuals without CVD independent of atherosclerotic plaque, according to a study in the Journal of the American Heart Association.

Researchers conducted an extension of the Chinese Multiprovincial Cohort Study to evaluate the independent effect of lipoprotein(a) on the long-term risk for ASCVD and the potential joint association of lipoprotein(a) and carotid plaque with ASCVD risk in populations free of CVD.

Participants aged 45 to 80 years had examinations for demographic characteristics and measurements of traditional risk factors in 2002 and 2007. The current analysis included 5471 individuals with complete data.

In the 15-year follow-up (mean, 11.7 years; median, 11.5 years; 64,111 person-years), 539 initial ASCVD events (226 coronary heart disease [CHD] events, 332 ischemic stroke events) occurred.

The participants (2822 women) had a mean age of 60.0±7.9 years, and their median lipoprotein(a) level was 11.5 (IQR, 6.2-22.9) mg/dL. Of the cohort, 2403 participants had lipoprotein(a) levels of less than 10.0 mg/dL, 2074 had lipoprotein(a) levels of 10.0 to 29.9 mg/dL, 579 had lipoprotein(a) levels of 30.0 to 49.9 mg/dL, and 415 had lipoprotein(a) levels of 50.0 mg/dL or higher.

In a comparison with individuals who had lipoprotein(a) levels of less than 10.0 mg/dL, the multivariable adjusted hazard ratio (aHR) was 1.62 for ASCVD incidence (95% CI, 1.19-2.21), 1.70 for CHD incidence (95% CI, 1.17-2.49), and 1.45 for ischemic stroke incidence (95% CI, 1.07-2.39) for participants with lipoprotein(a) levels of 50.0 mg/dL or higher.

According to Kaplan–Meier analysis, individuals with lipoprotein(a) levels of 50.0 mg/dL or higher had a significantly increased risk for incident ASCVD (log-rank P =.014), with a 10-year ASCVD incidence of 11.7%. An independent association of lipoprotein(a) levels was observed for ASCVD incidence, CHD incidence, and ischemic stroke incidence after adjustment for prevalent carotid plaque.

Additional analysis was performed in participants stratified by high lipoprotein(a) (≥30.0 mg/dL) vs low lipoprotein(a) (<30.0 mg/dL) and prevalent carotid plaque (present plaque vs absent plaque). Compared with individuals who had a low lipoprotein(a) level and were absent of plaque, ASCVD risk was significantly increased in participants with high lipoprotein(a) and present plaque (HR, 4.18; 95% CI, 1.47-6.92) and those with low lipoprotein(a) and present plaque (HR, 2.27; 95% CI, 1.04-3.41) after adjustment for known risk factors. A significant difference in ASCVD risk occurred between groups with lipoprotein(a) levels of 30 mg/dL or higher vs levels of less than 30.0 mg/dL with carotid plaque (P =.026).

An increased lipoprotein(a) level and prevalent plaque had a stronger association with CHD incidence compared with ischemic stroke incidence. A significant interaction was found between lipoprotein(a) and carotid plaque on ASCVD risk (P_interaction =.042). Kaplan-Meier analysis demonstrated that individuals with high lipoprotein(a) and present plaque had the greatest risk for ASCVD incidence (log-rank P <.001).

Among several limitations of the study, the total mass of lipoprotein(a) was measured in long-term frozen blood samples without repeated freezing and thawing, which may have led to a preferential decrease and false lower lipoprotein(a) levels, and there are potential unaccounted residual confounding factors. In addition, few participants had an elevated lipoprotein(a) level and prevalent carotid plaque at baseline.

“Findings in this study show that lipoprotein(a) and early vascular disease are of great value in identifying high cardiovascular risk and guiding lipid-lowering treatment,” the study authors wrote.

This article originally appeared on The Cardiology Advisor