A study testing whether use of a commercially available continuous glucose monitoring device is as effective as traditional blood tests for diagnosis of diabetes in heart or lung transplant recipients thought to be free from diabetes at least 1-year after transplant surgery.

Study design: A prospective study comparing the effectiveness of a commercially available continuous glucose monitoring system (Freestyle Libre2, Abbott Diagnostics) to gold-standard 75-gram oral glucose tolerance test for diagnosis of post-transplant diabetes mellitus (PTDM) in heart and/or lung transplant patients thought to be free from PTDM at least 1-year after heart or lung transplantation. Study participation involves completion of an outpatient 72-hour oral glucose tolerance test (as per professional society recommendations) followed by continuous glucose monitoring via a FreeStyle Libre sensor. The sensor is a minimally invasive device applied during a study visit to the hospital outpatient clinic by a study investigator. The sensor is painless and worn on the back of the non-dominant arm for 2-weeks. Data collected by the sensor is uploaded remotely and shared with study investigators via the LibreView platform. At the end of 2 weeks the participant removes the sensor as per manufacturers instructions and completes a patient experience survey via email link to a secure REDCAP database.