UC Davis Health research has found that people who received a kidney from a living donor with a history of smoking face a higher risk of transplant failure. Transplant failure, known as graft loss, occurs when the transplanted kidney permanently stops working. The highest risk was among patients whose donors had a substantial smoking history.

The new findings come from one of the largest studies to examine the impact of donor smoking on kidney transplant outcomes.

The study, published this month in Kidney360, analyzed data from 88,490 living donor kidney transplant recipients in the United States. The recipients underwent transplantation between 2004 and 2022 and are part of the Organ Procurement and Transplantation Network database.

Researchers found that recipients of kidneys from donors with any history of smoking experienced a 13% higher risk of all-cause graft loss compared with recipients of kidneys from donors who never smoked. Also, donor smoking history was associated with an 18% increase in the odds of acute rejection during the first year after transplant.

The greatest risks were observed among donors with more than 20 pack-years of smoking exposure. A pack-year is the equivalent of smoking one pack of cigarettes a day for one year.

Compared with recipients of kidneys from never-smokers, recipients of these organs from heavy users faced a:

• 29% higher risk of graft loss
• 24% higher risk of delayed graft function
• 32% higher risk of acute rejection

“Our findings suggest that smoking history, particularly heavy smoking exposure, should be considered during living donor evaluation and counseling,” said UC Davis pediatric nephrologist Machi Kaneko McBee, the lead author of the study. “At the same time, living donor transplantation remains a highly beneficial treatment option and smoking history alone should not automatically disqualify an otherwise suitable donor.”

The study also found that kidneys from former smokers performed better than those from active smokers. This suggests that smoking cessation prior to donation may help reduce transplant risks. However, the duration of smoking abstinence did not significantly alter long-term graft survival outcomes.

Study co-authors are Daniel Tancredi and Lavjay Butani of UC Davis Health.

Read the study.