Thursday, December 17, 2015

Donor smoking and recipient outcomes in kidney transplantation

I evaluated a young kidney donor candidate in clinic a few days ago and although he did not have any obvious medical issues and was an excellent candidate, he has been smoking half-a-pack a day of cigarettes for the last 10 years. I recommended that he needed to quit smoking, not only for his health, but also the recipient’s. For kidney transplant candidacy, recipients are strongly encouraged to stop smoking before and after transplantation. there is data that recipients with a history of smoking have a 2.1-2.3 times greater risk of poor graft survival

Different guidelines have different recommendations on how to manage tobacco use prior to transplantation on donors. This is what the living donation guidelines around the world state about managing smoking on donors prior to donation:

-In the Unites States, the most recent OPTN/UNOS guidelines from 2014, recommend only assessment for smoking but they don’t make any recommendations in regards to management prior to transplantation. No source of evidence is given.
-The Consensus Statement on the Live Organ Donor state that smokers can be considered if they are tobacco free for 6 months prior to donation; no smoking history is preferable.
-The 2013 ERBP (European Best Practice Guidelines) recommends to patients to stop smoking prior to transplantation (1C level of evidence)
-The 2011 British Transplantation Society guidelines state that donors should be encouraged for smoking cessation (B1-moderate quality of evidence, “we recommend”), frequent exercise and weight loss.
-The 2005 Amsterdam Forum Guidelines advices smoking cessation at least 4 weeks before donation, based on expert opinion.
-The 2010 Spanish Society guidelines, SEN-ONT recommend smoking cessation 4 weeks prior to surgery and patients are encouraged to stop smoking definitely. No level of evidence is given.

A 2007 survey of 132 U.S. kidney transplant programs found that 80% of programs have a smoking policy when evaluating living donors. 35% of programs accept current smokers as living donors, and 36% require donors to commit to quitting before surgery. 20% of programs do not have a smoking policy and only 7% routinely exclude smokers. Only 2 programs perform toxicology screens to verify smoking cessation.

Furthermore, in this paper the authors performed a retrospective study of kidney donors in a single center. They included 100 donors and 100 recipients; they found 29 donors with smoking history (16 with previous tobacco exposure but quit at the time of donation and 13 active smokers at the time of surgery) and 71 non-smoker donors. They also reported that donor’s smoking status has an effect on creatinine change at 1 and 6 months; for instance, recipients who received kidneys from donors with history of tobacco use had lower cGFR at one year, 44.1 mL/min per 1.73 m2 in comparison to recipients’ cGFR of 54.7 m mL/min per 1.73 m2 who received grafts from non smokers. In regards to graft survival, although not statistically significant, recipients with grafts from smokers had a higher rate of graft failure in comparison to the other group (6/13, 46% versus 5/30, 17%). No DGF was reported. The authors also reported the most recent followup for donors and found out that smokers had a greater change in creatinine than non-smokers (57% vs 40%) and there was not a significant difference even if smokers quit smoking prior to surgery. No donors had hypertension at the most recent follow up (approximately 144 days after surgery, for both groups)

In a most recent paper, the authors compared donor and recipient outcomes from kidney donors with active smoking history. They included 602 living donors (156 patients with active smoking) and they found out that smoking did not affect graft survival at the time of evaluation (HR = 1.19, P = 0.52) and was not associated with perioperative complications, but it had an impact on recipient’s survival at 10 years (HR = 1.93, p <0.01 vs HR = 1.74, p = 0.048). The authors acknowledge that recipient smoking was not examined in detail.

Smoking cessation is difficult for patients and generally the success rate is about 5% at any given attempt. In one of our paired kidney exchange (PKE) meetings, we were reviewing a case about a donor from another program in whom smoking cessation was not strongly advised. It’s important to know that complete smoking cessation is not a requirement for donation and recipients enrolled on a PKE program should be well informed about donor’s smoking status as well, especially if the recipient’s donor is healthy. Regardless, living donation is far superior and given the available evidence (or lack of it), transplant centers should strongly continue to advise smoking cessation to living donor candidates. Larger studies need to be done to establish a definitive link between living donor smoking and recipient graft and survival outcomes.

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