Plasma levels of the fibrin degradation product d-dimer are indicative of hypercoagulability and thrombotic events. However, the value of this biomarker in predicting events beyond 5 years and its association with other risk factors is unclear. Simes et al. now show that d-dimer levels predict long-term risk of cardiovascular events and death in patients with stable coronary disease, independently of and in addition to traditional risk factors and biomarkers. d-Dimer levels also predict cancer incidence and mortality in this patient cohort.

Simes et al. analysed data from 7,863 patients with myocardial infarction or unstable angina who had participated in the LIPID trial. d-Dimer levels were measured ≥5 months after the acute coronary syndrome, that is, after the period of hypercoagulability. Higher d-dimer levels were associated with traditional cardiovascular risk factors at baseline, including old age, history of hypertension, and high levels of B-type natriuretic peptide. During the first 6 years of follow-up, high d-dimer levels were associated with significantly increased risks of major coronary and cardiovascular events and with venous thromboembolism compared with low d-dimer levels (all P < 0.001), even after adjustment for traditional cardiovascular risk factors. At 16 years of follow-up, higher d-dimer levels were an independent predictor of all-cause mortality (HR 1.59, P < 0.001), cardiovascular mortality (HR 1.61, P < 0.001), cancer mortality (HR 1.54, P < 0.001), noncardiovascular and noncancer mortality (HR 1.57, P < 0.001), and cancer incidence (HR 1.16, P = 0.02). Inclusion of d-dimer level increased the net reclassification index for all-cause mortality by 4.0 and for venous thromboembolism by 13.6. “These results support an association of d-dimer with fatal events across multiple diseases and demonstrate that this link extends beyond 10 years' follow-up,” state Simes and colleagues, who conclude that d-dimer levels should be considered in risk prediction tools and clinical management decisions.