The Bavarian thromboembolie risk cohort study(BATER)

Objective: Familiar venous thromboembolic disease (VTE) is known to be related with factor V Leiden mutation (RVL), but also with other genetic markers. It is the objective to investigate of the BATER-study in a representative Bavarian cohort, and to assess whether they could predict VTE events. This paper shortly describes the study protocol, gives an overview of planned substudies, and provides first results of the historic cohort analysis. Patients and methods: The baseline survey of the cohort study of Bavarian women aged 18-49 years (random sample from the population) was performed in two samples in 1996 and 1997. It was planned to estimate prevalence and predictive value of potential markers of VTE in a historic - prospective as well as concurrent approach with annual follow-up of the cohort. This representative cohort should build a basis for nested case-control studies and serve as a reference group for other analytical epidemiological studies in young women. 1685 women were ascertained (response rate 61%), underwent an inquiry, and provided blood samples for a blood bank; for this paper, complete data are available from 1650 women. Labaratory parameters were measured to determine APC resistance, FVL-mutation, anti-thrombin-, protein C and S deficiency, and were correlated to the results of a detailed, life-time history of thrombembolic events. Results: The prevalence of FVL mutation in the sample was 5.7% (95% confidence interval 4.6-6.6%). Other genetic VTE risk markers were observed to be less frequent than 1%. The positive predictive value (pPV) of FVL mutation for a VTE event is about 7%, but for a positive family history of VTE (first grade relatives) 3% only. Conclusions: VTE events are rare in the German population of young women, even in cases of FVL mutation. A positive family history is rarely associated with the occurrence of VTE in women under 50 years of age, and the predictive value of FVL mutation is low. Therefore, a screening for FVL mutation is not justified unless there is suspicion of a high VTE risk for other reasons.