Range of published estimates of venous thromboembolism incidence in young women

OBJECTIVE: This review was conducted to show the full range of incidence estimates published for venous thromboembolism (VTE) in women depending on study design and to suggest a more reliable estimate for women of reproductive age. METHODS: A literature search was performed to identify studies on the incidence of VTE in women. Incidence rates were compiled from studies with different methodologies and varying methodological quality. Algorithms were used to estimate VTE incidence from more reliable studies in young women. RESULTS AND DISCUSSION: The literature shows two levels of VTE incidence rates: community/cohort studies and database studies. The estimated VTE incidence for women of reproductive age was 5.5-13.5 and 3.8-12.2 in community and cohort studies, respectively, but only 0.7-3.8 per 10,000 women-years (WY) in database studies. This difference is probably attributable to methodological problems associated with some database studies. CONCLUSION: The VTE incidence in women of reproductive age is likely to be in the range of 5-10 per 10,000 WY. These rates for the background incidence are clearly higher than the reference figures that are often utilized in the comparison with users of hormonal contraception (0.5-1 VTE per 10,000 WY).