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Combined novel risk factors raise coronary event rates



– Individuals with both elevated lipoprotein(a) levels and a family history of coronary heart disease are at a considerably higher long-term risk of atherosclerotic cardiovascular disease and coronary heart disease events than those with one risk factor alone, according to results from a large clinical study presented at the American Heart Association scientific sessions.

“Elevated lipoprotein(a) levels or a positive family history of coronary heart disease each is independently associated with cardiovascular disease risk,” said Anurag Mehta, MD, of Emory University School of Medicine, Atlanta. “This study showed that the presence of both an elevated Lp(a) level and a positive family history has an additive joint association with long-term cardiovascular risk.”

Dr. Mehta reported on an analysis of 12,149 individuals participating in the Atherosclerosis Risk in Communities (ARIC) study. All study participants were free of cardiovascular disease at the time of enrollment. The researchers measured Lp(a) levels and ascertained family history by self-report. Forty-four percent of the study participants had a family history of coronary heart disease (CHD), and 23% were black.

Median follow-up of study participants was 21 years, over which time 3,114 atherosclerotic cardiovascular disease (ASCVD) and 2,283 CHD events occurred.

Black participants had a significantly higher average plasma Lp(a) concentration than white persons, at 16.7 mg/dL vs. 5.7 mg/dL. However, plasma Lp(a) levels between participants with either a positive or a negative family history of CHD were similar on average, 7.6 mg/dL and 7.8 mg/dL, respectively.

The study pooled black and white ARIC participants by race-specific Lp(a) levels (quintiles) and stratified them into four different groups: 1. positive family history and an elevated race-specific Lp(a) level (quintile 5); 2. positive family history and nonelevated race-specific Lp(a) level (quintiles 1-4); 3. negative family history and elevated race-specific Lp(a) level; and 4. negative family history and nonelevated race-specific Lp(a) level. “There was an increase in the proportion of participants with a family history of CHD across race-specific Lp(a) quintiles, highlighting the fact that family history is associated with race-specific Lp(a) levels,” Dr. Mehta said.

“We observed that the ASCVD incidence was higher among participants with an elevated Lp(a) level or a family history of CHD as compared with participants with nonelevated Lp(a) levels and no family history,” Dr. Mehta said. “The highest ASCVD incidence was noted among participants with an elevated Lp(a) level as well as a positive family history.” Among those patients, the cumulative incidence of ASCVD events was nearly 25%, compared with 22% for those with a positive family history and nonelevated Lp(a) levels (group 2) or those with a negative family history but elevated Lp(a) levels (group 3), and 18% for those with negative family history and nonelevated Lp(a) levels.

Results for the cumulative incidence of coronary events trended similarly, Dr. Mehta noted: around 22% for group 1, 19% for group 2, 17% for group 3, and 14% for group 4.

“Having an elevated Lp(a) level as well as a family history of CHD was associated with a higher adjusted hazard for ASCVD and coronary events,” he said. Group 1 patients had a 43% greater risk for ASCVD and 68% greater risk for CHD, respectively, compared with a 16% and 30% greater risk for group 2, and 20% and 27% greater risk for group 3.

“Our findings indicate that these easily measurable nontraditional risk markers can help identify those at an elevated long-term CVD risk and may be useful for informing CVD prevention strategies among asymptomatic individuals,” Dr. Mehta said.

Dr. Mehta had no financial relationships to disclose.

SOURCE: Mehta A et al. AHA scientific sessions, Abstract AT.AOS.03 119.

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