OBJECTIVE: High Lp(a) (lipoprotein[a]) cause cardiovascular disease (CVD) in a primary prevention setting; however, it is debated whether high Lp(a) lead to recurrent CVD events. We tested the latter hypothesis and estimated the Lp(a)-lowering needed for 5 years to reduce CVD events in a secondary prevention setting. Approach and Results: From the CGPS (Copenhagen General Population Study; 2003-2015) of 58 527 individuals with measurements of Lp(a), 2527 aged 20 to 79 with a history of CVD were studied. The primary end point was major adverse cardiovascular event (MACE). We also studied 1115 individuals with CVD from the CCHS (Copenhagen City Heart Study; 1991-1994) and the CIHDS (Copenhagen Ischemic Heart Disease Study; 1991-1993). During a median follow-up of 5 years (range, 0-13), 493 individuals (20%) experienced a MACE in the CGPS. MACE incidence rates per 1000 person-years were 29 (95% CI, 25-34) for individuals with Lp(a)<10 mg/dL, 35 (30-41) for 10 to 49 mg/dL, 42 (34-51) for 50 to 99 mg/dL, and 54 (42-70) for ≥100 mg/dL. Compared with individuals with Lp(a)<10 mg/dL (18 nmol/L), the multifactorially adjusted MACE incidence rate ratios were 1.28 (95% CI, 1.03-1.58) for 10 to 49 mg/dL (18-104 nmol/L), 1.44 (1.12-1.85) for 50 to 99 mg/dL (105-213 nmol/L), and 2.14 (1.57-2.92) for ≥100 mg/dL (214 nmol/L). Independent confirmation was obtained in individuals from the CCHS and CIHDS. To achieve 20% and 40% MACE risk reduction in secondary prevention, we estimated that plasma Lp(a) should be lowered by 50 mg/dL (95% CI, 27-138; 105 nmol/L [55-297]) and 99 mg/dL (95% CI, 54-273; 212 nmol/L [114-592]) for 5 years.

CONCLUSIONS: High concentrations of Lp(a) are associated with high risk of recurrent CVD in individuals from the general population. This study suggests that Lp(a)-lowering by 50 mg/dL (105 nmol/L) short-term (ie, 5 years) may reduce CVD by 20% in a secondary prevention setting.