Female doctors’ patients live longer.

Heard this odd bit of medical science on Marketplace this morning. A new study of 1.5 million patients found that those treated by doctors who were women have a 5-percent better chance of survival:

Elderly patients treated by female physicians have a 5 percent better chance of living after getting out of the hospital. Put another way – if you were to replace all the male doctors in the study with women, 32,000 fewer people would die a year.

“I think the most surprising thing is that we found something. You know, why would gender matter,” said Dr. Anupam Jena, one of the study authors.

It may surprise some, considering the push for equality in the medical field. Now here come these results that threaten to upend that notion, not with the prejudice of the past, but with data that is the future. The results are based on 1.5 million hospital patients and 58,000 doctors. But even with that, Jena said they wanted to be sure. So the team checked obvious explanations, like women keeping their patients in the hospital longer, different post-hospital referrals, or just spending more money.

“None of those things emerged,” said Jena.

This is the first large study to look at how gender impacts patient outcomes. One thing to keep in mind is the effect is modest.

“The way to think about that is if you were a hospital administrator and you were going to reassign 149 patients to female physicians, then you might see this benefit of one life saved,” said University of Chicago’s Dr. Vineet Aurora, who is not affiliated with the research.

Jena’s instinct tells him what’s driving this statistical difference is how female physicians tend to approach problems and make decisions. He compares it to how he and his wife would rent a car and car seat for their toddler.

“The way I do that is I Google ‘car service,’ find the first thing that comes up and then I make a decision. She will go through probably five to ten different web pages, and look through all the Yelp reviews,” said Jena.

There’s more on this in The Atlantic; you can read the original research at JAMA Internal Medicine.