Women are underrepresented in safety and efficacy studies for high-risk cardiovascular devices, based on a review of 123 studies for 78 devices. The results were published online March 1 in Circulation: Cardiovascular Quality and Outcomes.
"There have been no analyses of gender bias in studies submitted for [Food and Drug Administration] approval of medical devices," despite a 1994 requirement to do so, said Dr. Sanket S. Dhruva of the University of California, San Francisco, and colleagues.
The researchers reviewed data involving high-risk cardiovascular devices that received premarket approval from the FDA from 2000 through 2007.
Overall, 34 studies (28%) did not report the sex of the study participants, and 67% of the participants in the studies that reported gender were male. The number of women enrolled in the studies remained stable over the 8-year study period, the researchers noted (Circ. Cardiovasc. Qual. Outcomes 2011;4:165-71.
Of the 123 studies, 107 were reviewed for gender bias comments or analysis. One study that included such a comment and 15 studies that did not include gender bias comments were excluded because they had fewer than 50 patients.
The FDA requires gender bias comments and analyses for all studies, but only 50 (41%) of the studies in this review included a gender bias comment or analysis. Of these, 47 (94%) included analysis of the findings by gender, and 12 (26%) of these described any gender-based difference in device safety or efficacy.
Of the 57 studies without a gender bias comment, 6 (11%) reported sex-specific data or analysis.
In 36 (29%) of the studies, the researchers wrote that the gender distribution in the study reflected the disease distribution or the referral population for the device.
In addition, 22 of 123 studies (18%) included a statement citing a random selection of men vs. women or that no gender selection bias occurred.
In 80 studies, the total number of patients and the percentage of men were identified, and the researchers found discrepancies in 38 (48%) of these. Most (84%) of the discrepancies were due to larger numbers of men included in the study than the percentage suggested.
Few studies provided raw data or statistical analyses in the FDA Summaries of Safety and Effectiveness Data (SSEDs), the researchers noted.
The study findings were limited by the inclusion of only publicly available SSEDs and meeting materials from the Circulatory System Devices Panel. However, the FDA held workshops in 2008 on "the study and analysis of sex/gender differences in cardiovascular medical device trials reviewed by the FDA," which suggests efforts to enroll more women in cardiovascular device studies and to report gender-specific data, the researchers noted.
Dr. Dhruva had no financial conflicts to disclose.