Effects of GLP-1 Receptor Agonists and SGLT-2 Inhibitors in Heart Transplant Patients with Type 2 Diabetes: a Case Series

Background Type 2 diabetes mellitus (T2D) is common in post-heart transplant patients. Commonly used T2D medications, especially insulin, can promote weight gain and are not associated with cardiovascular (CV) benefits. Glucagon-like Peptide-1 receptor agonists (GLP-1 RA) and Sodium-Glucose Cotransporter-2 inhibitors (SGLT2i) are two drug classes that produce CV benefits in T2D and promote weight loss with minimal risk of hypoglycemia. Their use has not been previously evaluated in this particular group, and there have been theoretical concerns about safety in immunosuppressed patients. Methods Patients with T2D are sequentially referred by the Heart Transplant program to the Cardiometabolic Center of Excellence (CMCE) at our institution, allowing minimal selection bias. CMCE provides treatment algorithms that emphasize the use of cardioprotective T2D medications. We analyzed this initial series of transplant patients with T2D who have been on GLP-1 RA and/or SGLT-2i with at least two visits at CMCE. Results Among 15 patients, the mean age was 59.4 ± 2.6 years, 66.7% were males, 73.3% were Caucasians, 33.3% had history of ischemic cardiomyopathy and baseline eGFR was 53.5 ± 7.9 mL/min/1.73m2. The median time from transplant was 4.6 (1.6 - 10.5) years. The median follow-up time at CMCE was 5.4 (2.8 - 10.9) months. At baseline, 73% were on insulin, 40% on Metformin, 13% on Sulfonylurea, 13% on Dipeptidyl peptidase-4 inhibitors, and 7% on Thiazolidinediones. Following initiation of therapy at CMCE, 86.7% of patients were on a combination of GLP-1 RA and SGLT-2i, while the rest were taking only GLP-1 RA. Overall, the median total daily insulin requirements decreased substantially from 94 (40.5 - 124) to 34 (5 - 60) units at latest clinic visit; p = 0.003. Further, median hemoglobin A1c dropped from 7.7% (7.3 - 9.5) to 6.6% (6 - 8.5); p = 0.007. There was also a significant reduction in mean body weight (241.9 ± 35.8 at baseline vs. 217.1 ± 34.2 lbs at follow-up; p = 0.001), and mean body mass index (34.9 ± 4.5 vs. 31.1 ± 3.7; p = 0.001). Only one patient experienced side effects as one episode of severe nausea with Liraglutide that resolved when switched to Semaglutide. No infectious complications (including urinary tract or genital mycotic infections) were observed. Conclusions In this limited case series, combination therapy with GLP-1 RA and SGLT-2i was well tolerated in heart transplant patients and associated with favorable results in insulin requirement, hemoglobin A1c, and body weight.