Survival following lung transplant (LTx) remains significantly lower than after other solid organ transplants. Diabetes (DM) is a mortality risk factor not comprehensively studied in LTx recipients. Notably, the relation of time of DM onset versus survival and actual causes of excess mortality associated with DM have not been described. We determined DM status, DM diagnosis date and all-cause mortality in 386 adults who underwent consecutive LTx at our institution from 1/1/2001- 31/7/2010. The relationship of DM to survival both as a categorical and time dependent variable was studied.

Fifty-three percent of patients had DM. Overall median survival was 5.2 (95% CI 3.8-6.6) years. At study end, 52% of patients had died, of whom 64% had DM. Estimated median survival was 10 years in patients without DM, 5.0 (3.3-6.8) years in patients with DM pre- and post-LTx, and 4.3 (3.1-5.5) years in patients with new-onset DM. As a time dependent covariate, DM was the strongest risk factor for mortality, HR 5.1 (3.6-7.2). The main cause of death in all patients surviving >90 days, irrespective of diabetes status, was bronchiolitis obliterans syndrome. 

This study suggests that DM is a key but under-recognised and under-valued contributing factor to the poor survival in lung transplant recipients. Future studies to delineate the mechanisms underlying the adverse outcomes and to determine whether improved glycaemic control could improve survival in LTx recipients are warranted.