Sex and Gender Differences Affect Treatment

• By Hope Lafreniere
• November 3, 2017

The Laura W. Bush Institute for Women’s Health held their annual Sex and Gender Differences Symposium on October 27 at Texas Tech University Health Sciences Center (TTUHSC). The keynote speaker Alyson McGregor, MDMA, FACEP, director of the Division of Sex and Gender Emergency Medicine and associate professor at the Warren Alpert Medical School of Brown University, focused on physiological differences between men and women, and how these differences play a role in treatment and research.

“Compare the genomes between members of the same sex and you will find a 0.1 percent difference between these people,” McGregor said. “But if when compared between a man’s genome and a woman’s, the difference in the genomes is nearly fifteen times higher. The XY and XX chromosomes are not just located in our gonads, they are in every cell in our body. People think these two chromosomes only change our physical traits, but it changes everything from how our bodies react to medications to higher prevalence of certain disorders among the sexes.”

McGregor compared instances of certain diseases manifesting more often in men and women. Men have higher instances of cardiovascular disease, sudden death, suicide, aneurysm, impulsivity, cardiomyopathy, autism and anti-social behavior; whereas, women are more prone to auto-immune diseases, depression, arrhythmia, hip fracture, high cholesterol, irritable bowel, migraine and Alzheimer’s disease.

“These diseases also manifest differently,” McGregor said. “A woman complaining of pain is more likely to be prescribed an anti-anxiety medication because she is anxious about being in pain, but a man will likely be prescribed an opioid.”

McGregor asked students to consider the following scenario: a woman comes into the clinic saying she has discomfort in her chest, telling her doctor that she has a lot of tight deadlines to make at work. Her doctor prescribes her an anti-anxiety drug. She comes back with the same issue; each time she is prescribed a new pill to try to alleviate her symptoms. Some pills cannot be taken without another, compounding her medications.

“What we see when this happens is Torsades,” McGregor said. “Women have longer QT intervals than men. When we continue adding medications that increase this QT interval, bit by bit, we can see a stacking effect between multiple overlapping prescriptions.  I see this in my rounds every day.”

Torsades de pointes is a condition that occurs when the heart’s resting interval, called the QT interval, between beats becomes too long, resulting in tachycardia that can lead to death.

McGregor also pointed out the disparity in research. The National Institutes of Health began requiring the consideration of sex as a biological variable in 2016 to help catalog the differences between a treatment’s effectiveness in men and women. In the past, women were labeled a protected class in research studies and could not be used in research. 

“Researchers used to use men as a homogeneous research subject, which discounts the differences between men and women when it comes to testing,” McGregor said. “Using a disproportionate amount of men in research studies caused tragic results in several studies. One research study on Thalidomide, a popular sedative used in the sixties, failed to account for sex and gender differences, and, as a result, women of childbearing age taking Thalidomide gave birth to malformed babies. In order to protect women, they placed a moratorium in using women as subjects.”

McGregor told the students that communication is paramount in treating patients and in research. Personalized medicine that takes into account both sex and gender improves outcomes for both men and women.

“There is a pattern to see men’s symptoms of disease as typical and women’s as atypical,” McGregor said. “If we reserve atypical for truly atypical cases, we can move forward and really save lives. What we as doctors can do is identify sex and gender differences and the clinical manifestations. We also must take into account the limits on testing between drug interactions and the differences between sex specific thresholds and medicinal efficiency. Lastly, we need to mitigate our bias to appropriately diagnose and treat our patients.”