An analysis of the Dubbo study suggests elevated Lp(a) is an independent and significant predictor of recurrent CHD in older people over a 16-year period.
Elevated levels of Lipoprotein(a) are an independent and significant predictor of recurrent coronary heart disease (CHD) in people aged 60 years or older, according to new research.1
The 16-year analysis of the Dubbo study suggested older people with prior CHD and Lp(a) readings in the top 20% of the population distribution (>355 mg/L) experienced a 53% excess risk of a recurrent CHD event, compared with those in the lowest 20% of the population distribution (<50 mg/L).
“This finding adds to growing evidence of a relationship between increased Lp(a) and the risk of recurrent CHD,” Leon Simons, lead author and an associate professor from the School of Clinical Medicine at the University of New South Wales Sydney, said in a statement.2 “It is well-established that people who have already experienced CHD are at very high risk of another event. Our new results indicate that new therapeutics in development that aim to reduce elevated Lp(a) might help prevent recurrent disease. However, the potential clinical benefit of therapy to reduce elevated Lp(a) is yet to be confirmed.”
Although previous research has suggested that high Lp(a) levels are an important risk factor in CHD development, most studies have investigated the risk in the context of a first CHD event. Results from the Dubbo study previously showed that citizens with Lp(a) readings ≥276 mg/L experienced a 46% greater chance of a first CHD event, compared with those with lower Lp(a) readings (<51mg/L).
The current analysis looked at whether elevated Lp(a) is predictive of a second or recurrent CHD event over 16 years. The study population consisted of 607 subjects with prevalent CHD aged ≥60 years excluded from the original analysis of the Dubbo study, given the increased risk of further CHD events in those already manifesting CHD. At study entry, investigators defined prevalent CHD as a previous myocardial infarction and/or angina reported by questionnaire, and/or resting electrocardiogram (ECG) changes during the baseline examination. Incident CHD events over the study period were determined via hospitalization and death records, as well as postal surveys conducted every 2 years to confirm vital status.
Over 16 years of follow-up, investigators identified 399 incident CHD cases. Upon analysis, the team found the median Lp(a) in those with a recurrent CHD event was 130 mg/L, compared to 105 mg/L in those who did not have a recurrent event. Data showed 26% of people with a recurrent CHD event and 19% of people without an event had Lp(a) levels of >300 mg/L; meanwhile, 18% of people who experienced a recurrent CHD event and 8% of people who did not showed Lp(a) levels of >500 mg/L.
In the population with prior CHD, the analysis showed the 53% excess risk of a recurrent CHD event in the top 20% of the population distribution, compared with those in the lowest 20% of the population distribution, was independent of other risk factors.
Based on the analysis, Simons and colleagues indicated that elevated Lp(a) is an important predictor of recurrent CHD in an older population. They noted upper Lp(a) reference levels of 500 mg/L or 300 mg/L appear to be appropriate for the identification of high-risk individuals who may benefit from a more intensive intervention.
“While current medications, such as statins, are often prescribed to lower ‘bad cholesterol’ in patients at higher risk of cardiovascular disease, these do not have any major or proven impact on elevated Lp(a),” Simons said.2 “But, there is hope for the future – as some novel therapeutics that are designed to lower the levels of Lp(a) are currently in the advanced stages of clinical development.”