Increased Lipoprotein(a) tied to elevated risk of recurrent coronary heart disease

While previous research has indicated that high levels of Lp(a) are also an important risk factor in the development of CHD, most of these studies have looked at Lp(a) levels and the risk of a first CHD event. The current study looked at whether elevated Lp(a) is predictive of a second or recurrent CHD event. It involved 607 Australians aged 60 years and over, all with prevalent CHD, who were followed for 16 years as part of the Dubbo study. There were 399 incident CHD cases.

The researchers found that:

• The median Lp(a) in people who had a recurrent CHD event was 130 mg/L, compared to 105 mg/L in those who did not.

• 26% of people who had a recurrent CHD event – and 19% of those who did not – had Lp(a) levels of >300 mg/L.

• 18% of people who had a recurrent CHD event – and 8% of those who did not – had Lp(a) levels of >500 mg/L.

In senior citizens with prior CHD, elevated Lp(a) in the top 20% of the population distribution (>355 mg/L) predicted a 53% excess risk of a recurrent CHD event, compared with those in the lowest 20% of the population distribution (<50 mg/L) over 16 years of follow-up. This prediction was independent of other risk factors.

“We conclude that elevated Lp(a) is an important predictor of recurrent CHD in older people. Upper reference Lp(a) levels of 500 mg/L or 300 mg/L both appear to be appropriate for identifying those at higher risk who may benefit from more intensive risk reduction interventions,” says Associate Professor Simons. “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). 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.”

A key limitation of this longitudinal study is that the baseline data were collected in 1988-89. However, while there may have been other influences affecting CHD risk over the years of follow-up, especially with statin therapy, it can be reasonably assumed that people with elevated Lp(a) at the start of the study will maintain that status during the whole period.

Reference:

Leon A. Simons, Judith Simons, Lipoprotein(a) and the risk of recurrent coronary heart disease: the Dubbo Study, https://doi.org/10.1080/03007995.2023.2214434