High prevalence of abnormal glucose metabolism in young adult patients with complex congenital heart disease

BackgroundAbnormal glucose metabolism (AGM) adversely impacts morbidity and mortality in patients with chronic heart failure. No data on AGM in adult patients with congenital heart disease (ACHD) are available.MethodsTo assess the AGM in ACHD and compare the results with their clinical characteristics, we performed a 75-g oral glucose tolerance test to detect AGM, that is, insulin resistance, impaired glucose tolerance, and diabetes mellitus, in 205 consecutive ACHD (24 ± 8 years), including 16 unrepaired patients, 67 Fontan patients, 122 postbiventricular (BV) patients, and 27 healthy controls (27 ± 5 years).ResultsAll ACHD groups had a high prevalence of AGM (unrepaired, 43.8%; Fontan, 43.3%; BV, 46.7%; control, 3.7%; P < .001). In the 2 postoperative groups, the Matsuda index was decreased (P < .0001), and greater waist circumference, liver dysfunction, higher plasma renin activity, and diuretic use were associated with AGM. Although male gender was associated with AGM (P < .01), baseline glucose and lipid metabolic variables did not correlate with the 75-g oral glucose tolerance test–induced hyperglycemia (area under the plasma glucose curve [AUC-PG]) in the Fontan patients but did correlate in the BV patients. The AUC-PG correlated inversely with exercise capacity (P < .05) in the 2 postoperative ACHD groups, and the AGM ACHD had a high incidence of future cardiac events (P < .05), especially the Fontan patients with diabetes mellitus (P < .01).ConclusionsComplex ACHD have a high prevalence of AGM, and this newly recognized pathophysiology should be considered in managing long-term survivors of complex ACHD.