TORONTO -- The family of an 81-year-old Toronto man in need of a kidney transplant has taken to putting up flyers pleading for a donor with the hope someone will step forward.

The efforts of Marcel Rozen's wife, who posted the notices on message boards around the city, have highlighted the difficulties faced by thousands of Canadians waiting for a kidney transplant.

"I'm on a waiting list, but how long do you wait? That's the question," Rozen said in an interview. "It's very hard. And I'm not a young kid either, so that doesn't help"

Rozen's kidneys function at 5 per cent or less of their normal capacity. Every night for nearly three years, he has hooked himself up to a dialysis machine that, over the course of nine hours, cycles eight litres of medical fluid through his body.

"You don't sleep that well," he said. "Sometimes when it drains the liquid from your body it starts to hurt, so even when you sleep you wake up."

Rozen will remain on dialysis until he can get a transplant, he said, but doctors told him when he began his nightly treatments that it could take up to eight years to get a new kidney.

There are currently over 1,000 people in Ontario waiting for a kidney, the Ministry of Health said.

Each of them will spend, on average, four years waiting for a transplant. In 2017 alone, 37 Ontarians died while on the waiting list for a kidney, the ministry said.

"Priority for patients on the wait list is based on medical urgency, blood type and ... DNA type matching and wait times," ministry spokesman David Jensen said.

In Ontario, a deceased donor's kidneys are matched to a patient on the waiting list by the Gift of Life Network, the province's organ and tissue donation agency.

"One kidney (from each deceased donor) is allocated to patients in the transplant program within the donor's region first and, if no match is found, the kidney is then allocated to a patient listed at another provincial transplant program," Jensen explained. "The other kidney is shared nationally for specific patients first and, if no match is found, the kidney is allocated to a patient at a provincial transplant program."

Advocates say the greatest challenge facing Canadians in need of a kidney transplant is an overwhelming lack of available donors.

"The need for organs, in particular kidneys, outpaces the supply," said Elizabeth Myles, national executive director of the Kidney Foundation of Canada.

There were over 3,400 Canadians on the kidney waiting list in 2016, but only about 1,730 transplants performed that year, she said.

"Our pool for available kidneys is through a deceased donor, somebody who has registered to donate their organs after they have passed away, (but) only about three per cent of deaths qualify for organ transplant," Myles said.

"And then there's the living donors … but that is certainly not a decision that somebody would make lightly. The kidney is a complicated part of your larger body so there is a lot of challenges or steps one needs to go to."

Patients often have a loved one willing to donate a kidney, but they may not be a match, said Myles.

Canadian Blood Services runs a kidney "exchange" program, however, that connects mismatched pairs of donors and recipients with people they do match with.

For instance, if someone wants to donate a kidney to their partner but they are not a match, Blood Services will connect the couple with another set of donor-recipient candidates who don't match each other but could benefit from the partner's kidney.

This donation chain can include several pairs of people exchanging kidneys, Myles said.

In Rozen's case, doctors have ruled out his wife and his brother-in-law as potential donors because they are not healthy enough to survive with only one kidney, Rozen said.

"Everybody else in my family, most of them are dead so I just don't have anybody else," he said.

Rozen's wife, Julia, has consequently taken on the search for a donor, posting flyers around Toronto asking for help.

She was inspired by a recent story about a New Jersey man who went to Disneyworld wearing a T-shirt emblazoned with his phone number and the words, "In need of kidney O Positive." Photos of the man were shared on social media and, ultimately, led to him finding a donor, the Washington Post reported.

"She said, 'well if he can do it, I can do something similar,"' Rozen said, noting that his family has since received six or seven calls from people who want to help but have yet to be approved for donation by a doctor.

"What is going to happen to me tomorrow or the next day? I don't know," he said. "You just hope for the best."