More men are treated with hemodialysis for end-stage kidney disease than women, according to a new international study examining sex-specific differences in treatment.

The study, published Tuesday in the journal PLOS Medicine, examined data from more than 200,000 hemodialysis patients in 12 different countries, including Canada.

Hemodialysis is the medical procedure used to remove waste from a patient's blood when their kidneys are no longer able to remove waste naturally. Hemodialysis is used to treat advanced kidney failure.

In the study, patient data obtained from the Dialysis Outcomes and Practice Patterns Study (DOPPS) was examined to compare the demographic characteristics and mortality rates of male and female hemodialysis patients.

The DOPPS data on mortality rates were then compared to general mortality rates from the World Health Organization's Human Mortality Database.

The study found that in every age group, more men were on hemodialysis than women. Overall, 59 per cent of male patients were on hemodialysis compared to 41 per cent of women.

The study also found that women's survival rates after receiving hemodialysis were virtually equal to men's, but women were not receiving hemodialysis as early. This could lead to higher female mortality before treatment, the study notes.

The study concluded that the natural survival advantage among women in the general population appears to be reduced in female hemodialysis patients.

"These data indicate that the survival advantage that women have over men in the general population was markedly diminished in hemodialysis patients with end-stage renal disease," the authors said.

The study also found demographic differences between male and female patients undergoing dialysis. Compared to women, the men were younger, less frequently obese, less frequently depressed, more frequently married, and had a higher incidence of heart disease.

The study's authors note that although some of the sex-specific treatment differences may be related to biological factors, other factors may include patient care and patient knowledge about kidney disease.

Canadian data

Dr. Janet Roscoe, a nephrologist fromThe Scarborough Hospital in Ontario, told CTV News that she was surprised to see that fewer women were receiving dialysis compared to men.

"When I looked at the numbers I was actually quite startled at the difference in the male/female ratio," she told CTV News. "It does leave one wondering why that is."

She said that after reading the study she asked for statistics on Ontario dialysis patients, and saw similar findings.

Roscoe agrees that more research needs to be done that looks into why women are underrepresented among dialysis patients.

She said that one factor that may be coming into play is that female patients don't recognize their own symptoms as a sign of a larger health problem.

"It may be that women just suck up to feeling tired or dragged out, and just think 'It's normal' or that they're not sick. Or it may be that there is a bias against referring women to a nephrologist," she said.

"We have to look at this very seriously, and I think there is an opportunity for a lot of learning from this."

Patient Brenda Miron said that since she started dialysis last January her health has improved immensely. After starting the procedure, 68-year-old lost more than 100 pounds of fluid in a month, and has been able to return to work.

She told CTV News that she initially didn't want to start dialysis because a family member who was on dialysis had died.

"I didn't want to go through the same thing," she said. "I was afraid that I would end up like them, passing away. But I’m so glad I went on it."

She eventually agreed after she was told that if she refused the treatment she probably wouldn't survive more than six days.

Now, looking back, she says she has no regrets. "It was the best thing I ever did. I feel like a million dollars. I feel better now than I did, even before I got sick," she said.

Miron is certain there are other women out there who are worried about starting dialysis, but said they should seek more information to ease their minds.

"It is a frightening thing and if you don't know anything about it, it's even more frightening," she said. "I sure hope that others out there that are afraid, take heed."

With files from CTV News Medical Correspondent Avis Favaro and Senior Producer Elizabeth St. Philip