Doctors perform a kidney transplant. (Linda Davidson/The Washington Post)

Marcello Tonelli is associate vice president of research at the University of Calgary. John Gill is a clinician scientist and professor of medicine at the University of British Columbia and a member of the board of directors for the American Society of Transplantation. They are both former presidents of the Canadian Society of Nephrology.

Kidney transplants are universally acknowledged as the best treatment for kidney failure. Compared with remaining on dialysis, transplant recipients live longer, have better quality of life, are more likely to raise a family, have fewer symptoms and incur far fewer health-care costs.

After a successful transplant, keeping the kidney functional requires lifelong use of immunosuppressive medications, which prevent the recipient's body from rejecting the new organ. These medications provide excellent value for money since they allow the patient and society to reap the benefits of kidney transplantation.

As researchers from Canada, we've studied health care for those affected by kidney disease in the United States and other developed nations. Since 1972, Medicare has provided coverage to patients with kidney failure, regardless of age or disability status. However, while there is no time limit for dialysis patients, kidney transplant recipients who are not otherwise eligible for Medicare lose their coverage 36 months after they receive their transplant — leaving many unable to pay for immunosuppressive medications. Without access to these medications, patients eventually lose their transplants and require dialysis treatment instead.

This policy is irrational, since Medicare has already paid for the kidney transplant and will pay to treat the patient with dialysis — despite its markedly higher cost — when the transplanted kidney fails.

Our research has shown the United States stands alone in allowing this situation to exist. All other wealthy nations recognize the benefits of immunosuppressive medications and cover their costs for patients with functioning kidney transplants.

Funding these medications would save hundreds of millions of dollars annually in direct medical costs. Between 2008 and 2012, the most recent data available, the average annual Medicare cost for a transplant recipient was $22,000 compared with $47,000 for a dialysis patient. But those costs are much higher — at $84,000 — for patients who suffered transplant failure and had to return to dialysis. And if you look at only the patients who died after a transplant failure, average costs skyrocket — to $201,000.

Failing to provide lifelong coverage also dishonors the gift of life made by thousands of kidney donors each year, since denying such access means that some of these gifts will be in vain. We estimate that in the past five years, 7,700 patients have needlessly lost their kidney transplants, 900 patients have prematurely died and Medicare has squandered nearly $1 billion in health-care costs that could have been averted if only funding for immunosuppressive medications had been secured.

Even more frustrating, a legislative remedy — commonly known as "the immunosuppression bill" — is already available. Lawmakers first proposed the bill in 2011, but it has repeatedly stalled.

This bill would allow Medicare-eligible kidney transplant recipients to receive life-saving immunosuppressive medications for as long as their transplant continues to function. Ironically, failure to pass this bill into law during the Obama administration may in part be due to its bipartisan support, which gave little political advantage to passing it.

It is impossible to justify continued inaction: The problem and its solution are both straightforward. The machinery required to fund, prescribe and deliver immunosuppressive medications is in place. All that is needed is the political will to pass legislation and allow U.S. patients to benefit.