Ohuchi H, Negishi J, Hayama Y, et al. - Given that a high prevalence of abnormal glucose metabolism (AGM) is seen among Fontan patients, researchers sought to describe AGM as well as to gain clarity regarding its link with Fontan pathophysiology via this study including 276 consecutive Fontan patients (aged 19 ± 7 years). Among participants, they prospectively assessed AGM with plasma glucose dynamics (mg/dL; fasting glucose [FPG], and maximum glucose increase PG-spike]) during oral glucose tolerance test and hemoglobin A1c (HbA1c). In the initial analysis, they found that impaired glucose tolerance and diabetes mellitus (DM) were often seen (38.4% and 4.7%, respectively) in this population, and the presence of DM was predicted independently by positive family history, high HbA1c, and high central venous pressure. The new onset of DM was predicted by positive family history, high liver enzymes, and AGM. An 8.7 times higher mortality rate was reported in patients with FPG ≤ 74 and/or PG-spike ≥ 85 vs those without. Progression of AGM was evident even in young adult Fontan patients. Limited predictive value for progression was seen with HbA1c. Also, the crucial role played by oral glucose tolerance test was highlighted when it comes to exposing unique Fontan AGM and predicting all-cause mortality.