Sex-Based Results Still Missing in CV Publications

(UPDATED) Sex-specific reporting in cardiovascular publications improved marginally over a recent 10-year period, but not for the types of research relied upon for regulatory approvals and practice guidelines, new research shows.

Stephani C. Wang, MD (University of California, Irvine), and colleagues, writing in the Journal of Women’s Health, note that just 13% of cardiovascular articles published between 2006 and 2015 reported on sex differences. That proportion remained relatively unchanged over the study period. Broken down by publication type, clinical trials and meta-analyses showed no gains in the reporting of results for men and women.

“Clinical trials are the ones that drive the guidelines, so it’s very important to improve this,” senior author Radmila Lyubarova, MD (Albany Medical Center, Albany, NY), told TCTMD.

Wang, Lyubarova, and colleagues performed a “bibliometric” analysis filtering for cardiovascular studies based on terms in the first author affiliation field as well as sex-based reporting using relevant terms in the article title or abstract. Further analyses looked for trends over time, funding source, and publication type.

In all, 189,543 cardiovascular publications were identified, of which just 24,615 appeared to include sex-specific reporting. While both the overall number of papers published, as well as the number of papers with sex-specific details, grew over the decade, the proportion of papers including sex-specific information remained unchanged. Broken down by type, the proportion of papers with sex-specific information remained static or dipped slightly for clinical trials, meta-analyses, and review articles. However, it increased marginally for “general articles”—mostly observational or registry studies.

Additional analyses looking at funding sources for US-based publications (based on first-author’s institutional affiliation) indicated that the proportion of sex-specific results in research funded by the National Institutes of Health (NIH; which ranged between 30% and 40% of the overall sample) actually declined over the study period, despite growing calls both in the US and internationally to improve sex-based reporting.

A Stagnant Picture

To TCTMD, Lyubarova stressed that the terms used to identify cardiovascular publications and filter out those that included sex-based reporting were “crude,” as was the method of zeroing in on US publications (based on the first author alone). Nevertheless, she said, as an estimate of proportional changes, they paint a picture of stagnancy.

“Clinical trials and meta-analyses [provide] the data that our guidelines and position statements are based on, so it’s very important to improve research and include more women in clinical trials—and subsequently also meta-analyses—so as to be able to share gender-specific outcomes and have gender-specific guidelines, as well,” she said. Trials that exclude older patients, she added, shoulder a large share of the burden when it comes to underrepresentation, since women typically develop cardiovascular disease later in life.

Commenting on the paper for TCTMD, Muhammad Shahzeb Khan, MD (University of Mississippi Medical Center, Jackson), pointed out that sex “can have important impact[s] on cardiovascular diseases epidemiology, pathogenesis, treatment response, and prognosis.”

Khan led an analysis in 2020 that reviewed clinical trials used to approve 35 cardiometabolic drugs between 2008 and 2017, finding that women made up just 36% of study participants.

This newest study, on top of prior research, points to an ongoing problem. “The article by Wang et al is particularly relevant as it shows there have been no significant increase in sex-specific publications for the recent 10-year period,” Khan said. That said, he added, it’s important to remember that this study counted only articles that mentioned sex-based differences if specific terms were mentioned in the title or the abstract. “The majority of the studies [may] report such results in the full text results section or tables,” he noted.

An additional caveat, said Lyubarova, is that the Research for All legislation, mandating representative numbers of women and minorities in federally funded research, was only passed in 2016. Subsequently, an NIH policy amendment stipulating that NIH-funded trials include adequate representation of women and minority groups only went into effect in 2017. The current study, however, only included research published prior to these initiatives.

“Hopefully,” write the authors, “legislation will change this trend in the next decade.”

Study co-author Annabelle Santos Volgman, MD (Rush College of Medicine, Chicago, IL), pointed to an additional factor holding back the field. “Cardiology remains a male-dominated field and the papers being published that report on sex differences in cardiovascular disease are mostly by women who are interested in this,” she pointed out in an email. “Until there are more women in cardiology, the numbers of papers looking at sex differences may not increase significantly.”