Glucometabolic responses during Glucose Tolerance Test: a comparison between known diabetes and newly detected diabetes after acute myocardial infarction.
BACKGROUND
Glucose Tolerance Test (GTT) newly detects diabetes (new diabetes) in a substantial number of patients without a history of diabetes (known diabetes) after acute myocardial infarction (AMI). Patients with new diabetes have poor outcomes, despite their lower HbA1c levels.


METHODS
This study consisted of 53 patients with new diabetes and 47 patients with known diabetes who underwent GTT 1 week after AMI. Sixty-eight patients with normal GTT and 78 patients with impaired glucose tolerance served as control. Plasma glucose and insulin were measured at fasting, 30 m, 60 m and 120 m after glucose load. Peak glucose-fasting glucose was used as a measure of glucose fluctuation. Homeostasis model assessment of insulin resistance and the Stumvoll's equations were used to assess insulin sensitivity and ß-cell function, respectively.


RESULTS
Fasting glucose (115 ± 20 mg/dl versus 129 ± 41 mg/dl, p=0.02) and hemoglobin A1C (5.7 ± 0.5% versus 6.7 ± 1.4%, p<0.001) in new diabetes were significantly lower than known diabetes. Insulin sensitivity was similarly impaired in both new diabetes and known diabetes (3.2 ± 2.2 versus 3.0 ± 1.9, p=0.58). Impairment of insulin secretion was less severe in new diabetes than in known diabetes. Peak glucose-fasting glucose was significantly greater in diabetic patients than inpatients with normal GTT (75 ± 30 mg/dl, p<0.001) and impaired glucose tolerance (95 ± 24 mg/dl, p<0.001), with no difference between new diabetes and known diabetes (156 ± 36 mg/dl versus 165 ± 57 mg/dl, p=0.36).


CONCLUSIONS
These findings suggested that insulin resistance and exaggerated glucose fluctuation could be attributable to poor outcomes after AMI in patients with new diabetes.
Ishihara
Masaharu
M
Department of Cardiology, Hiroshima City Hospital, 7-33, Moto-machi, Naka-ku, Hiroshima 730-8518, Japan. ishifami@fb3.so-net.ne.jp
Inoue
Ichiro
I
Kawagoe
Takuji
T
Shimatani
Yuji
Y
Kurisu
Satoshi
S
Nakama
Yasuharu
Y
Kagawa
Eisuke
E
Dai
Kazuoki
K
Ootani
Takayuki
T
Ikenaga
Hiroki
H
Morimoto
Yoshimasa
Y
Ejiri
Kentarou
K
Oda
Nozomu
N
D000368:Aged; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000378:metabolism / Q000401:mortality; D005260:Female; D018149:Glucose Intolerance / Q000175:diagnosis / Q000378:metabolism / Q000401:mortality; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000378:metabolism; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality*; D011237:Predictive Value of Tests; D012307:Risk Factors
D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007328:Insulin; C517652:hemoglobin A1c protein, human