Inferior Outcomes for Patients Developing New-Onset Post-Transplant Diabetes Mellitus after Haploidentical Hematopoietic Cell Transplant

The mortality rate triples for the 50% of patients diagnosed with new-onset post-transplant diabetes mellitus (PTDM) after HLA-identical allogeneic hematopoietic cell transplant (HCT) (Griffith, BBMT 2011). Haploidentical HCT (haplo-HCT) with post-transplant cyclophosphamide (PTCY) is increasingly utilized for patients with hematological disorders but without a conventional HLA-matched donor; however, the effects of PTDM after haplo-HCT is unknown. We examined the incidence, outcomes, and risk factors for PTDM in patients undergoing haplo-HCT. Patients receiving haplo-HCT with PTCY at Vanderbilt-Ingram Cancer Center (n= 65) were retrospectively analyzed for PTDM diagnosis (defined as a random blood glucose ≥200 mg/dL). Exclusion criteria included non-haplo-HCTs, second HCT, or pre-existing diabetes mellitus. The primary outcome was the incidence of new-onset PTDM by day 100. Secondary outcomes included: cumulative incidence (CI) of grades 2-4 graft-versus-host disease (GVHD), time to systemic steroids, PTDM risk factors, overall survival (OS), disease free survival (DFS), and non-relapse mortality (NRM). PTDM was diagnosed in 14 (21.5%) patients at a median of 18 days after haplo-HCT (range, 8-72 days). Hyperglycemia preceded grade 2-4 GVHD and steroids in 12 (85.7%) patents. Clinical characteristics including ablative conditioning and GVHD did not predict PTDM development (Table 1). OS was decreased in the PTDM group (Figure 1). Among haplo-HCT recipients with cancer (n= 41) DFS was lower and the CI of relapse was increased in PTDM patients (Figure 1). Similar to HLA-identical transplants, PTDM occurs frequently, precedes alloreactivity, and leads to inferior survival following haplo-HCT. Interestingly, glucose metabolism appears to be associated with relapse risk. Prophylaxis/treatment of PTDM may improve outcomes after conventional and haplo-HCT.