One-Hour Postload Hyperglycemia Is a Stronger Predictor of Type 2 Diabetes Than Impaired Fasting Glucose.
BACKGROUND
Subjects with normal glucose tolerance (NGT) but 1-h postload glucose ≥ 155 mg/dL (NGT-1h-high) exhibit an intermediate cardiometabolic risk profile between individuals with NGT and impaired glucose tolerance (IGT).


OBJECTIVE
This study aimed to evaluate whether NGT-1h-high subjects have different cardiometabolic characteristics and an increased risk of type 2 diabetes compared with individuals with isolated impaired fasting glucose (IFG).


METHODS
A cross-sectional analysis was performed on 595 nondiabetic subjects who underwent an oral glucose tolerance test and an euglycemic hyperinsulinemic clamp in an ambulatory care setting. In addition, a longitudinal analysis was performed on 392 individuals, who were reexamined after a followup of 5.2 ± 0.9 y.


METHODS
Insulin sensitivity, beta-cell function, and risk of developing diabetes were measured.


RESULTS
Subjects with NGT-1h-high have a significant reduction of peripheral insulin sensitivity and beta-cell function, assessed by the disposition index, compared with either 1-h postload glucose < 155 mg/dL (NGT-1h-low) or IFG individuals, but not compared with IGT. Among the 392 subjects studied in the longitudinal analysis the incidence rate of type 2 diabetes over the follow-up period was 2.9, 16.7, 12.5, and 31.4% for subjects with NGT-1h-low, NGT-1h-high, IFG, and IGT, respectively. In a Cox proportional hazard regression analysis the risk of developing diabetes for NGT-1h-high subjects was 4.02 (95% confidence interval [CI] 1.06-15.26); an even higher risk (6.67; 95% CI, 2.09-21.24) was observed in subjects with IGT, but not in the isolated IFG group (1.91; 95% CI, 0.44-8.29).


CONCLUSIONS
NGT-1h-high subjects exhibit a higher risk of developing diabetes than those with IFG or NGT-1h-low, likely due to decreased insulin sensitivity and beta-cell function.
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Teresa Vanessa
TV
Fiorentino
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Maria Adelaide
MA
Marini
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Francesco
F
Andreozzi
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Franco
F
Arturi
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Elena
E
Succurro
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Maria
M
Perticone
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Angela
A
Sciacqua
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Marta Letizia
ML
Hribal
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Francesco
F
Perticone
Department of Medical and Surgical Sciences (T.V.F., F.An., F.Ar., E.S., M.P., A.S., M.L.H., F.P., G.S.), University Magna Graecia of Catanzaro, Catanzaro, 88100 Italy; and Department of Systems Medicine (M.A.M.), University of Rome-Tor Vergata, Rome, 00133 Italy.
Giorgio
G
Sesti
D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis*; D005215:Fasting / Q000097:blood*; D005260:Female; D015309:Glucose Clamp Technique; D005951:Glucose Tolerance Test; D006801:Humans; D006943:Hyperglycemia / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D008875:Middle Aged
D001786:Blood Glucose