High prevalence of diabetes before and after lung transplantation: target for improving outcome?

Background: Diabetes increases morbidity and mortality of lung transplantation. However, the reported prevalence of diabetes varies post-transplantation partly due to lack of detection protocols.

Aim: To determine the prevalence of diabetes in patients (i) waitlisted for lung transplant and (ii) early post-transplantation.

Methods: We analysed patients on the St Vincent's Heart Lung database from 1 April 2014 to 30 September 2015 on the waitlist (Study 1) and those transplanted (Study 2). Standard of care required all non-diabetic patients to have an oral glucose tolerance test (modified for patients with cystic fibrosis (CF) to screen for CF-related hyperglycaemia (CFRH) (plasma glucose ≥8.2 mmol/L at 60 or 90 min).

Results: Study 1 included 114 patients (32 with CF and 82 without CF). Of 30 CF patients with glycaemic data, 27 (90%) had abnormal glucose metabolism: 18 had diabetes and nine had CFRH. In 50 patients without CF, 20 (40%) had abnormal glucose metabolism: eight had diabetes and 12 had impaired fasting glucose and/or impaired glucose tolerance. Study 2 included 78 transplanted patients (25 with CF and 53 without CF). Fourteen CF patients had pre-existing diabetes and seven had pre-existing CFRH. All but one patient were diagnosed with diabetes post-transplantation. Hence, diabetes prevalence in CF patients post-transplantation was 96%. Among 53 transplanted patients without CF, seven (13%) had abnormal glucose metabolism but 30 (57%) were diagnosed with post-transplant diabetes.

Conclusion: There is a high prevalence of diabetes in lung transplant patients. Earlier endocrine participation in lung transplant services is likely to lower diabetes-related morbidity and mortality further.