Can a meta-analysis that included articles with high heterogeneity appropriately evaluate the risk of venous thromboembolism in users of combined hormonal contraceptives containing drospirenone or desogestrel? A reply to Rosa et al.

Concerns about the appropriateness of high heterogeneity in the meta-analysis evaluating the risk of venous thromboembolism in users of combined hormonal contraceptives are discussed in this reply to a critical response of the original study. The response claimed that some of the study’s meta-analyses were compromised by the high heterogeneity which affected two studies one pertaining to drospirenone and the other one to desogestrel. The authors acknowledge previously pointed out methodological flaws in the cohort studies. Finally taking into account the discussed limitations the authors consider that observational studies will not add relevant information and only well-designed prospective studies will help to better understand the real risks of hormonal contraception.