By Carolyn Y. Johnson

If male doctors were able to do as well as their female counterparts when treating elderly patients in the hospital, they could save 32,000 lives a year, according to a study of 1.5 million hospital visits.

A month after patients were hospitalized, there was a small but significant difference in the likelihood that they were still alive or had to be readmitted to the hospital depending on the gender of the doctor who cared for them.

Although the analysis can't prove the gender of the physician was the determining factor, the researchers made multiple efforts to rule out other explanations.

“If we had a treatment that lowered mortality by 0.4 percentage points or half a percentage point, that is a treatment we would use widely. We would think of that as a clinically important treatment we want to use for our patients,” said Ashish Jha, professor of health policy at the Harvard School of Public Health. The estimate that 32,000 patients' lives could be saved in the Medicare population alone is on par with the number of deaths from vehicle crashes each year.

For years, studies have suggested that men and women practice medicine differently. Women are more likely to adhere to clinical guidelines and counsel patients on preventive care. They are more communicative than men. But whether those differences have a meaningful impact on patients' well-being has been unclear.

The new study, based on an analysis of four years of Medicare data, found that patients treated by a female doctor had a little less than half of a percentage point difference in the likelihood they would die within a month of their hospitalization. There was a similar drop in patients having to go back to the hospital over that month. Those are not large differences, but Jha pointed out that major health policies aimed at improving mortality in hospitals and increasing patient safety had resulted in a similar drop in mortality over a decade.

To try to rule out other possible explanations for the difference — such as healthier patients's preference for female doctors — the researchers did an analysis where they looked solely at hospitalists, doctors who see patients who are admitted to hospitals and who are typically not chosen by patients. They also made sure patients had similar characteristics in the two groups. They compared doctors within hospitals, to avoid measuring a difference that could be accounted for by comparing a woman who worked at a rural community hospital with a man who worked at an urban trauma center.

Vineet Arora, an associate professor of medicine at the University of Chicago, praised the research but was cautious to read too much into the main result, pointing out that it was important to remember the effect might stem from multiple factors.

“It could be something the doctor is doing. It could be something about how the patient is reacting to the doctor,” Arora said. “It’s really hard to say. It's probably multi-factorial.”

What the study drove home for Arora, who works as a hospitalist, is that women are certainly not worse doctors than men — and they should be compensated equitably. A study published earlier this year found a $20,000 pay gap between male and female doctors after controlling for other factors, such as age, specialty and faculty rank, that might influence compensation.

She noted that female doctors, who are often being hired in their childbearing years, may face a subtle form of discrimination, in the worry that they will be less committed or that they will not work as hard when they have children.

“Having a female physician is an asset,” Arora said.

William Weeks, a professor of psychiatry at Dartmouth's Geisel School of Medicine, said that the researchers had done a good job of trying to control for other factors that might influence the outcome. He noted that one caveat is that hospital care is usually done by a team. That fact was underscored by the method the researchers used to identify the doctor who led the care for patients in the study. To identify the gender of the physician, they looked for the doctor responsible for the biggest chunk of billing for hospital services — which was, on average, about half. That means that almost half of the care was provided by others.

He said the finding deserves further investigation, but in the short term, the study underscores the idea that female doctors should be paid equally — particularly as there is a push toward payment systems that reward the value of the care and not the number of tests and procedures that patients receive.

To Judith Hall, a professor of psychology at Northeastern University, who has long studied the communication skills and attitudes of doctors of both genders, the research adds a crucial piece of evidence. Female doctors, she said, tend to be more patient-centered, talk about and factor in psychological and emotional factors, and are better judges of nonverbal cues. She does not think communication style alone is likely to account for differences in clinical outcomes, but she does not think it should be discounted.

Two decades ago, Hall gave a talk to a group that turned out to be predominantly male doctors and said all of the evidence suggested that women are better doctors. It did not go over well, she said.

“It takes a huge study like this to convince anybody, because it’s a very highly charged topic,” Hall said. “Women are the newcomers to this field.”