A donor’s smoking history and a recipient’s obesity increase the risk of severe primary graft dysfunction (PGD) in lung transplant patients, according to the results of a multi-institution study led by researchers at the Perelman School of Medicine at the University of Pennsylvania.

PGD, the major cause of serious illness and death after lung transplantation, affects up to 25% of lung transplant patients shortly after surgery, according to researchers.

The prospective, multicenter cohort study of risk factors for severe PGD after lung transplantation followed 1,255 lung transplant recipients at ten US lung transplant centers over a span of 8 years.

Investigators discovered that overweight recipients had an absolute 7% higher risk for PGD compared with normal weight; obese recipients had an 11% higher risk of PGD. They also found that lung recipients from donors who were smokers have an absolute 5% higher risk of developing PGD than those who received lungs from nonsmokers.

“Even though donor smoking is tied to higher death rates and incidence of Grade 3 PGD, this doesn’t mean we should prohibit smokers from donating lungs,” said lead study author Joshua Diamond, MD, MSCE, instructor of medicine in the Division of Pulmonary, Allergy, and Critical Care at Penn.

“Although PGD was higher after receiving a lung from a smoking donor compared with a non-smoking donor, other studies show that overall survival is significantly better than remaining on waiting lists for lung transplantation when donors with a smoking history are part of the donor pool. Given the limited pool of available lung donors, it’s simply not feasible to exclude patients who were previous smokers as potential lung donors.”

Several other risk factors were also identified, including certain types of lung disease and several surgical procedures often used to help sicker patients survive the surgery. In these cases, however, it is not clear if the fact that patients were sicker and needed the procedures explained the higher PGD rates or if the procedures themselves resulted in greater rates of PGD.