Breaking News: Women and Men are Different

It's hard to believe, I know. Women and men are different. This is going to be big, and I mean BIG.

Actually, we know it isn't big news, but it took awhile to notice that in clinical research trials. Which is why adoption of the inclusion policies by the National Institutes of Health (NIH) is so important for eliminating health disparities when conducting research trials.

NIH every year publishes its clinical research enrollment demographics for the year. I decided to take a look at the enrollment reports for 2007 and see how NIH is doing in meeting its inclusion policies.

First, I looked at enrollment of males and females in all trials (Phase I-III), and found that, overall, females are very well represented. However, I took this information one step further, and divided it into single-sex and mixed-sex studies.

A single sex study is one in which the researcher focuses on questions that involve either males or females, but not both. For example, they might be interested in treatments for ovarian cancer or testicular cancer, respectively. When I accounted for these trials. I saw that the vast majority of participants in mixed-sex trials were males.

I then looked at Phase III trials alone, because NIH policy focuses on inclusion specifically for this last phase. Again, my initial findings showed a higher proportion of women enrolled than men. When I further divided this into single- and mixed- sex, I found a more equal distribution of males and females in mixed sex studies.

So, it appears NIH is doing a pretty good job of meeting its stated policy goals for enrollment of women. However, I can’t help thinking that this policy may not be good enough.

Not all drugs make it to Phase III trials. What if we are overlooking drugs that might be more effective in women than men, but we don't see it because there aren't enough women in earlier trials? That drug might never make it to Phase III trials, and an entire population might miss out on a therapy that could really help them.

But beyond enrollment, when I looked at some independent publications to see how many clinical trials are actually asking the very obvious question: is there a difference between the reactions in males and females? The consensus: not many.

So either clinical researchers are not asking this question, or they are asking it, finding no differences, and not publishing this information. Either way, we need to know; so researchers, if you're reading this, start reporting!


This is Part 11 of 13 in our From Ideas to Treatments series.
Part 1 - From Ideas to Treatments
Part 2 - Basic Research: It Starts with an Idea
Part 3 - You're an Animal!
Part 4 - Can I care about animals and do research too?
Part 5 - Regulations for Animal Research
Part 6 - Clinical Research Trials
Part 7 - Patient Safety in Clinical Trials: IRB Approval
Part 8 - Recruitment
Part 9 - Health Disparities in Clinical Research
Part 10 - A Brief History of Inclusion Policies
Part 11 - Breaking News: Women and Men are Different
Part 12 - Including Minorities in Clinical Trial Research
Part 13 - Bringing From Ideas to Treatments Home