Compared with their counterparts in other countries, American women are more likely to not take their prescribed medications properly, or to not take them at all. And for a quarter of them, cost is why they skip necessary treatments.

A team from Columbia University reported those startling figures in the journal Health Findings, noting that American women fared worse than men.

The team used data from the Commonwealth Fund International Health Policy Survey of populations in 11 high-income countries, including the U.S., Australia, Canada,  Germany, and the U.K. They found among those ages 18 to 64, one in four U.S. women reported skipping medications because they were unaffordable, compared with one in seven men who said the same. The disparity in overall non-adherence to prescriptions between men and women in the U.S. topped all other countries in this age range. There were no significant female-male differences among older adults.

Part of the explanation could be women’s greater health needs and higher prescription use, but the numbers are not that far apart. From 2015 to 2016, 41% of U.S. men reported receiving one or more prescriptions, compared with 50% of women.

The employment-based insurance prescription drug coverage system or plans that require high patient contributions may disproportionally affect women, who are less likely to have full-time employment and more likely to be lower income.

The implications are obvious: If women choose to not fill or delay refilling prescriptions, skip doses or split pills, they risk not getting the full benefit for their treatment — making a bad situation even worse.