Association of fibrinogen γ' with recurrent thrombosis: a nested case-control study

Fibrinogen γ' is a natural variant of the fibrinogen γ chain, accounting for 10% to 15% of fibrinogen in human blood. Studies have found an association between fibrinogen γ' plasma levels and the risk of first-time arterial and venous thrombosis, but how fibrinogen γ' associates with recurrent thrombosis is unknown.

To investigate the association between fibrinogen γ' levels and recurrent thrombosis in patients previously diagnosed with arterial or venous events.

We conducted a nested case-control study of 265 patients who experienced arterial or venous thrombosis between 1995 and 2013. Patients were followed prospectively until recurrent thrombosis; we identified 113 cases (with recurrence) and 152 controls (without recurrence) matched for sex, age, and date of blood sampling. Baseline plasma fibrinogen γ' levels were compared between cases and controls. We used logistic regression to determine the association between fibrinogen γ' levels and the risk of recurrent thrombosis.

In the arterial group, cases had higher absolute and relative fibrinogen γ' levels (P < .01). Absolute increases of 50 μg/mL or relative increases of 5% were associated with odds ratios of recurrent thrombosis of 1.11 (95% CI, 1.00, 1.16; P < .01) and 1.31 (95% CI, 1.06, 1.63; P < .05), respectively. In the venous group, relative fibrinogen γ' levels tended to be lower in cases (P = .07) and were associated with a lower risk of recurrent thrombosis (odds ratio, 0.82; 95% CI, 0.62, 1.08).

In the arterial group, absolute and relative fibrinogen γ' levels were positively associated with the risk of recurrent thrombosis. In the venous group, relative fibrinogen γ' levels and recurrent thrombosis were inversely associated, but not significant.