BACKGROUND: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a regulator 
of LDL-cholesterol receptor homeostasis and emerges as a therapeutic target in 
the prevention of cardiovascular (CV) disease. This prospective cohort study 
analyzes risk prediction with PCSK9 serum concentrations in patients with stable 
coronary artery disease (CAD) on statin treatment.
METHODS AND RESULTS: Fasting PCSK9 concentrations were measured in 504 
consecutive patients with stable CAD confirmed by angiography. Oral glucose 
tolerance tests were performed in all patients without known diabetes. Patients 
were followed up for 48months. The primary outcome was the composite of 
cardiovascular death and unplanned cardiovascular hospitalization. Serum 
concentrations of PCSK9 predicted CV outcomes (PCSK9>622 ng/ml vs. <471 ng/ml: 
HR 1.55, 95%-CI 1.11-2.16, p=0.009). Higher PCSK9 concentrations were associated 
with female gender, hypertension, statin treatment, C-reactive protein, HbA1c, 
insulin, total cholesterol and fasting triglycerides, but not with LDL- or 
HDL-cholesterol. The association of PCSK9 levels with CV events was reduced 
after adjustment for fasting TG.
CONCLUSION: PCSK9 concentrations predict cardiovascular events in patients with 
coronary artery disease on statin treatment. Serum triglycerides are correlated 
with PCSK9 and modify risk prediction by PCSK9.