Thrombophilia testing in patients with venous thromboembolism. Findings from the RIETE registry

There is scarce information on the management habits with regard to thrombophilia testing in patients with venous thromboembolism (VTE).

RIETE is an ongoing registry of consecutive patients with symptomatic VTE. Aimed to estimate the extent to which thrombophilia test ordering patterns are consistent with the recommendations by a 2005 international consensus statement, we retrospectively compared the clinical characteristics of all patients tested for thrombophilia and those who were not tested.

Of 21367 patients enrolled, 4494 (21%) were tested for thrombophilia: 1456 (32%) tested positive, 3038 (68%) negative. The most common abnormalities were: Factor V Leiden (N=376), antiphospholipid syndrome (N=289), and prothrombin G20210A (N=263). Overall, 12740 (60%) patients met one or more criteria of the consensus statement: 7894 (37%) had a first episode of idiopathic VTE; 4013 (19%) were aged <50 years; 133 (0.6%) were pregnant women; 758 (3.5%) were using estrogens; 3375 (16%) had recurrent VTE. Of them, 3618 (28%) underwent thrombophilia tests, 34% of whom tested positive. The percentage of patients testing positive was significantly higher in those aged <50 years, with no differences between idiopathic or secondary, first episode or recurrent VTE. Finally, 876 (10%) of the 8627 (40%) patients meeting no criteria were tested. Of these, 208 (24%) tested positive.

Twenty-eight percent of patients meeting one or more criteria for thrombophilia testing, and 10% of those with no criteria were actually tested. Thus, a substantial proportion of thrombophilia ordering is not consistent with the recommendations made by the consensus statement.