Risk of recurrent venous thrombosis related to past provoking risk situations: follow-up of a cohort study.

Strategies targeting at classifying the risk for recurrent venous thrombosis are needed. We previously hypothesized, by studying a cohort of patients, that those who had 'survived' risk situations for venous thrombosis without developing it would, after a first venous thrombosis, have a low recurrence risk. Therefore, we re-evaluated the same cohort, now with a longer follow-up.