The causal effects of smoking on major comorbidity and mortality in the general population are well established. However, the influence of smoking exposure on kidney transplants remains uncertain. The aim of this study was to determine patient and graft specific outcomes for kidney allograft recipients stratified by any smoking exposure at a large UK centre.

Methods: Data was extracted by the Hospitals informatics team for all kidney transplants at the Queen Elizabeth Hospital, Birmingham between January 2007 and January 2015. Electronic patient records were manually searched to facilitate data linkage between various sources to create a comprehensive database of baseline demographics, donor details and clinical events.

Results: Of 1,140 patients transplanted, 280 (24.0%) had documented smoking exposure and were classified as ever smokers for analysis. Ever smokers were more likely to be male (71.5% v 56.0% p<0.001) and Caucasian (76.3% v 70.8% p=0.044)but there was no association with any other baseline demographic. There was no significant association between smoking exposure and mortality (8.8% v. 6.6% p=0.139) (median follow up 4.4 years). Ever smokers had higher rates of post transplant major morbidity including cancer (10.2% v. 4.8% p=0.002), diabetes (11.3% v. 7.2% p=0.029) and cardiac events (11.3% v. 4.4% p<0.001). Ever smokers had significantly increased risk of graft failure (21.5% v. 14.2% p=0.003), driven by death-censored graft losses (13.9% v. 9.0% p=0.016). Of the 502 patients that underwent biopsies, there were significant histological differences between the groups with higher rates of thrombotic microangiopathy (4.0% v. 1.7% p=0.029), acute tubular injury (16.8% v. 12.1% p=0.032) and chronic allograft damage (5.8% v.2.8% p=0.016). Renal function was also consistently inferior in ever smokers with higher creatinine levels at 12 months (185.68 mmol/l v 155.54 mmol/l p=0.018) with similar findings at 0, 1, 3, 6, 9, 36 and 60 months. Indeed, using a Cox regression model, smoking exposure was shown to independently increase overall graft loss.

Conclusion: This large single centre study demonstrates that smoking exposure is associated with negative post transplant outcomes; it increases patient morbidity, increases graft failure and consistently reduces renal function.

CITATION INFORMATION: Gillott H, Tahir S, Jackson-Spence F, Evison F, Nath J, Sharif A. Smoking Exposure Among Kidney Allograft Recipients and Outcomes After Transplant. Am J Transplant. 2016;16 (suppl 3).

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