Why Sex Bias Occurs in Clinical Trials and How We Can Change It

by Karen Appold •

Impacts of Disparity

When women are left out of clinical research, there are gaps in our knowledge of disease processes and how they might affect men and women differentially, Dr. Farzal said. Differences in treatment efficacy can also occur.

In otolaryngology, Dr. Senior noted differences in disease states and prevalence depending on sex. For example, benign thyroid nodules are much more common in women, as are thyroid cancers. While otosclerosis is histologically present in both men and women, the clinical diagnosis is much more common in women. “Not recognizing these sex differences and not studying them will result in large segments of the population being improperly treated,” he said.

Gender disparities can also impact patient care. If women don’t comprise a significant percentage of the researchers in a given field, important questions may be missed and gender bias can occur in terms of subjects, said Sujana S. Chandrasekhar, MD, a partner at ENT & Allergy Associates, LLP, in New York City. “Studies that don’t take into account women’s metabolism and concerns don’t honor the differences between women and men and may result in incorrect or harmful care for female patients,” she added.

Erynne A. Faucett, MD, pediatric otolaryngologist with the department of surgery in the division of otolaryngology at Phoenix Children’s Hospital in Arizona, said it’s important to be able to predict any sex-specific outcomes for better personalization of treatment and prevention strategies because there are sex-based differences in diseases of the head and neck. “Knowing how to manage and treat these disease processes in men and women is important,” she said.

Comparing Otolaryngology with Other Research

The bottom line is that sex bias in clinical trials remains prevalent in all medical disciplines. In general surgery, a review of 1,303 studies published in 2011 and 2012 from five general surgery journals revealed that 17.3% did not report participant sex and only 33% analyzed data by sex (JAMA Surg. 2016;151:1022–1030). In orthopedics, a slight improvement in sex-based analysis has been demonstrated, from 19% in 2000 to 30% in 2010 (Clin Orthop Relat Res. 2015;473:3700–3704).

In otolaryngology, deficiency in sex reporting and sex-based statistical analysis similarly exists but appears to be slightly better than those two disciplines. “Our work has shown that 91% of studies reported on participant sex, and only 2.1% had single-sex participants,” Dr. Senior said. Furthermore, slightly fewer than half of studies analyzed outcomes by sex (47%), and nearly two- thirds of studies had more than 50% or greater sex matching. In rhinology specifically, Dr. Senior found that participant sex was reported in 93% of studies, and only 0.5% included participants of a single sex. Sex-based statistical analysis was performed on 52% of studies.