Predictability and other aspects of post-transplant diabetes mellitus in heart transplant recipients

Background: Diabetes mellitus that develops after organ transplantation may predispose patients to further complications. We studied the value of pre- transplant oral glucose tolerance testing or maximum random plasma glucose, and HLA-DR3 and/or DR4 phenotype as predictors of post-transplantation dia betes mellitus in heart transplant recipients. Patients and Methods: In 228 cardiac allograft recipients (median age, 50 y ears; mean follow-up, 4.77 years), we used either pre-transplant oral gluco se tolerance testing results (Group I, n = 141)-excluding patients with pre -existing diabetes (n = 9)-or maximum random plasma glucose values (Group I I, n = 78) to study predictability of post-transplant diabetes. In addition , we investigated its relation to rejection treatment and clinical course. Results: Cumulative incidence of post-transplant diabetes (n = 43) was 19.6 %, 83% of which became manifest within 3 months post-transplant; pre-transp lant body mass index was higher (p < 0.01) in this group. Mortality did not increase. Of 123 patients in Group I who survived > 3 months, post-transpl ant diabetes occurred in 32% vs 16% of those with impaired and normal gluco se tolerance respectively (ns), and in 55% of patients with isolated post-l oad hyperglycemia (p < 0.05 vs normal). Maximum random glucose values (Grou p II) did not predict post-transplant diabetes. Prevalence of the HLA-DR3, DR4, and DR3DR4 phenotypes did not increase in post-transplant diabetes; re lation to rejection treatment was likely in 30%. Approximately 50% of post- transplant diabetes patients required only temporary drug treatment. Conclusions: The risk of post-transplant diabetes increased parallel to pre -transplant degree of glucose intolerance, but was considerable even in nor mal glucose tolerance. HLA-DR3 and/or DR4 phenotype was not a predisposing factor.