Diabetics Have Elevated Risk for Death After Lung Transplant

Barbara Boughton

June 18, 2013

SAN FRANCISCO — A new study is the first to find that type 2 diabetes is a leading risk factor for mortality after lung transplant and that diabetics have a 5-fold increased risk for death after the procedure.

In the study, 367 patients who underwent lung transplant at the Alfred Hospital in Melbourne, Australia survived just half as long after their surgery as those without type 2 diabetes, according to research presented here at ENDO 2013: the Endocrine Society 95th Annual Meeting.

"Diabetes was the most important risk factor for mortality, whether it was diagnosed before or after transplant," said lead researcher Kathryn Hackman, MD, from Monash University in Australia.

Clinicians at the Alfred Hospital had observed that their lung-transplant patients with diabetes not only suffered more complications after their surgery but were less likely to survive than those without the disease, Dr. Hackman told Medscape Medical News. "We wanted to research mortality after lung transplant based on diabetes status and also delve into whether the time of diagnosis made a difference," she said.

Asked to comment on the findings, Robert Vigersky, MD, from Walter Reed National Military Medical Center, Bethesda, Maryland, and a former president of the Endocrine Society, said that it has been known for some time that diabetes increases the risk for death in kidney-transplant patients, and this study now confirms a similar risk in lung transplant. The results point to the importance of screening for type 2 diabetes and the need for transplant surgeons and pulmonologists to be on the lookout for abnormalities of glucose metabolism, he stressed.

First Detailed Study on Diabetes and Risk for Death After Lung Transplant

In the study, researchers retrospectively reviewed the records of patients who underwent lung transplant between 2001 and 2010. The researchers excluded those who were diagnosed with diabetes shortly after surgery — within the first 3 months — since elevated hyperglycemia is a transient aftereffect of lung transplant.

Results indicated that whether type 2 diabetes was diagnosed before lung transplantation or afterward, the patients' survival after surgery was similar — and they died significantly earlier than those without the disease.

Among patients with type 2 diabetes, 122 of 195 patients died after their surgery vs 67 of 171 patients without the disease (63% vs 40%, P < .001). Those without diabetes had a median survival of 10 years, while diabetics diagnosed both pre- and posttransplant survived for a median of 5 years; this fell to 4.3 years if their condition was newly diagnosed after transplant.

After multivariate adjustment, type 2 diabetes was the leading predictor for mortality (hazard ratio [HR] = 5.6, P < .001), although the researchers considered other risk factors such as lung disease, cystic fibrosis, body mass index (BMI), smoking history, and age.

After type 2 diabetes, having high triglycerides was the most important risk factor for death (HR = 1.68). For all subjects, the most common cause of death was bronchiolitis obliterans syndrome, a form of chronic rejection of the transplanted lung.

Previous studies based on database information have found elevated rates of mortality among lung-transplant patients with diabetes, the researchers said. This is the first to provide a detailed look at diabetic status both before and after transplant, as well as other risk factors for early death, according to Dr. Hackman.

Unique Observations Should Inform Vigilant Approach by Doctors

"This is an interesting study because it points out some observations about lung-transplant patients with diabetes that haven't been made before," commented Dr. Vigersky, who was not involved in this study.

"We know that poor glycemic control causes kidney transplants to fail sooner. Now this study shows us similar information about lung transplants. But we don't know from the data exactly what aspects of diabetes played a part in the shorter life expectancy," he told Medscape Medical News.

The study points out the importance of screening for diabetes and the need for physicians involved in lung transplants to be on the lookout for abnormalities of glucose metabolism, he added.

ENDO 2013: The Endocrine Society 95th Annual Meeting. Abstract FP13-6, presented June 15, 2013.


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