Post-Transplant Diabetes Mellitus and the Risk of Acute Rejection in Heart Transplant

Abstract

The development of post-transplant diabetes mellitus (PTDM) is associated with an increased risk of acute rejection after kidney and liver transplantation, however, the outcomes after orthotopic heart transplant (OHT) have yet to be systematically studied. We sought to investigate whether there is any relationship between the development of PTDM and acute rejection after cardiac transplant. This was a single center retrospective review of 100 consecutive OHT patients between May 2015 and May 2018. A total of 39 patients with a documented history of diabetes mellitus were excluded from the study. Patients were divided into 2 groups: those who developed PTDM and those who did not. PTDM was defined by a hemoglobin A1C (HBA1c) ≥ 6.5 and/or a fasting blood glucose (FBG) ≥ 126 at 6 months post-transplant. Rates of rejection (ISHLT grading ≥ 1R/1B - 3R/3B) were compared between the 2 groups. Of the 61 patients (mean age 54.5 ± 11.9), 12 (19.6%) developed persistent PTDM at 6 months. Nine of the 12 patients who developed PTDM at 6 months had rejection compared to 9 of 49 patients who did not develop PTDM (75 % vs 18.37 %; p= <0.001 Figure 1). There was a positive correlation between the development of PTDM and the risk of rejection (r=0.632; p= <0.0001). Cumulative daily dose of prednisone pre-rejection as well as 6 months post-transplant was 21.4 mg ± 9.46 and 17 mg ± 10.73 respectively. Average time from OHT to rejection (N=18) was 2.3 months ± 2.47. Using adjusted regression to control for cumulative prednisone dose, age and weight, PTDM was associated with an increased risk of rejection (p= 0.002; CI 1.03-4.54). PTDM is associated with an increased risk of acute cellular rejection within 6 months post-OHT. Larger studies are warranted to examine whether any causal relationship exists between the development of PTDM and acute rejection in heart transplant recipients.