Background: In the absence of approved medication to lower high Lipoprotein (a) (Lp(a)), its deleterious effects might be mitigated by overall cardiovascular (CV) risk reduction. However, data on the relationship between increased Lp(a) and incident coronary heart disease (CHD) according to the distribution of modifiable CV risk factors (CVRF) at baseline are still scarce.
Objective: To evaluate the association between high Lp(a) and incident CHD in the general population, depending on the presence or absence of four major CVRFs (hypertension, diabetes, dyslipidemia, smoking) at baseline.
Methods: The present analysis includes 66,495 individuals from eight European prospective population-based cohorts, who were free of clinically diagnosed CHD at baseline (primary prevention setting). All participants were followed-up prospectively for the occurrence of a CHD event. The cohort was stratified according to CVRF burden at baseline in two categories: "zero or one CVRF” and ”≥2 CVRFs”, reflecting very low versus increased baseline risk, respectively. Fine and Gray competing risk-adjusted models were calculated for the association between Lp(a) mass (<90th (ref.) versus ≥90th percentile (pctl.) of Lp(a) distribution) and future CHD events.
Results: At baseline, the majority of CHD-free subjects demonstrated very low CV risk, having zero or one CVRF (overall n= 41,770), whereas 24,725 individuals reported ≥2 CVRFs. During a median follow-up of 9.7 years, 3,467 incident CHD events occurred. Despite being at very low absolute risk based on traditional CVRF, individuals with zero or one CVRF at baseline demonstrated a strong association between increased Lp(a) mass (≥90th pctl.) and future CHD events, which was comparable to the association observed among individuals with ≥2 CVRFs. The fully-adjusted sub-distribution Hazard Ratios [sHRs] for elevated Lp(a) were 1.38 (95% CI, 1.12-1.71) in individuals with zero or one CVRF versus 1.27 (95% CI, 1.10-1.46) in those having ≥2 CVRFs at baseline (P interaction between two groups 0.50).
Conclusion: Among CHD-free subjects, high Lp(a) was related to adverse outcome even in individuals with no or only one CVRF at baseline, thereby generating substantial challenges in mitigating Lp(a)-associated CHD risk in very low risk populations.
