Drospirenone‐containing oral contraceptive pills and the risk of venous thromboembolism: a systematic review of observational studies

Abstract

Systematic review of drospirenone: best studies show no or slightly increased VTE risk (versus levonorgestrel).

Severely biased review of studies assessing the risk of venous thrombosis in users of drospirenone‐containing oral contraceptives

“…Larivée et al state that the appropriate comparator for users of a COC with drospirenone should be users of a COC with another type of progestogen, not non‐users. I do not agree that a comparison with non‐users is irrelevant.…”

“…Larivée et al applied a minus to those studies that only included hospitalised women with VTE because, according to them, such a restriction should exclude outpatients. That criterion is not valid, however, because studies restricted to inpatients alone should provide the same rate ratios of VTE when users of different COCs are compared.…”

“…These include age (by far the most important confounder), previous thrombosis and current pregnancy. Pregnancy was not even mentioned in the list of risk factors by Larivée et al Studies including information about body mass index have all demonstrated that this risk factor for VTE is not a confounder, or is at best is a weak confounder . Lack of control for body mass index will underestimate the difference in risk between users of COCs with drospirenone and users of COCs with levonorgestrel, because users of COCs with drospirenone have been found to have a slightly lower body mass index than women on COCs with levonorgestrel, implying that these women appear to be at less risk compared with women on COCs with levonorgestrel …”

“…In a recent review, Larivée et al attempted to categorise 17 observational studies specifically assessing the risk of venous thrombosis (VTE) in users of combined oral contraceptives (COCs) with drospirenone. Such a review is relevant because of the divergent results in these studies, which could be due to bias in some of them.…”

Erratum

“…In the following article, the statement on disclosure of interests was not reproduced in the final manuscript on page 1497.…”