title: Post-challenge insulin concentration is useful for differentiating between coronary artery disease and cardiac syndrome X in subjects without known diabetes mellitus.
abstract: BACKGROUND
  Cardiac syndrome X (CSX) is characterized by angina pectoris but with patent coronary arteries. Our previous study demonstrated that subjects with CSX had a higher fasting insulin-resistance (IR) than the controls. However, few studies have investigated the degree of IR, including oral glucose tolerance test (OGTT)-derived indices and profiles of metabolic abnormalities between CSX and coronary artery disease (CAD).
  
  
  METHODS
  Ninety-two CSX and 145 CAD subjects without known diabetes mellitus (DM) underwent coronary angiogram (CAG) for angina pectoris and also agreed to receive OGTT and glycated hemoglobin (HbA1C) evaluations for screening abnormal glucose regulation and IR.
  
  
  RESULTS
  CAD group had more subjects with metabolically unhealthy obesity (52.4 vs. 31.5%, p < 0.001) than the CSX group. The CAD group had higher OGTT 2 h glucose and insulin (both p < 0.005) while fasting glucose, insulin and HOMA-IR were similar to those of CSX subjects. In the binary regression analysis, OGTT 2 h insulin and being metabolic unhealthy were significantly different between the CAD and CSX groups, but there were no significant differences in Matsuda index, fasting glucose, insulin, HOMA-IR, or HbA1C.
  
  
  CONCLUSIONS
  Post challenge OGTT 2 h insulin and being metabolic unhealthy were useful parameters in differentiating between CAD and CSX in subjects without known DM but suffered from angina pectoris and underwent CAG. Different degrees of IR and metabolic abnormalities might be implicated in the pathogenesis of micro vs. macro vascular coronary diseases.Trial registrationNCT01198730 at https://clinicaltrials.gov, Registered Sep. 8, 2010.
authors.affiliation: Cardiovascular Center, Taichung Veterans General Hospital, 1650 Taiwan Boulevard, Sec. 4, Taichung, 40705 Taiwan.|School of Medicine, National Yang Ming University, Taipei, Taiwan.|Department of Medicine, China Medical University, Taichung, Taiwan.
authors.forename: Kae-Woei
authors.initials: KW
authors.lastname: Liang
authors.affiliation: School of Medicine, National Yang Ming University, Taipei, Taiwan.|Division of Endocrinology and Metabolism, Department of Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.|Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan.|School of Medicine, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Wayne H-H
authors.initials: WH
authors.lastname: Sheu
authors.affiliation: Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan.|Tung-Hai University, Taichung, Taiwan.
authors.forename: Wen-Jane
authors.initials: WJ
authors.lastname: Lee
authors.affiliation: Cardiovascular Center, Taichung Veterans General Hospital, 1650 Taiwan Boulevard, Sec. 4, Taichung, 40705 Taiwan.|School of Medicine, National Yang Ming University, Taipei, Taiwan.
authors.forename: Wen-Lieng
authors.initials: WL
authors.lastname: Lee
authors.affiliation: Cardiovascular Center, Taichung Veterans General Hospital, 1650 Taiwan Boulevard, Sec. 4, Taichung, 40705 Taiwan.|School of Medicine, National Yang Ming University, Taipei, Taiwan.|School of Medicine, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Hung-Chih
authors.initials: HC
authors.lastname: Pan
authors.affiliation: School of Medicine, National Yang Ming University, Taipei, Taiwan.|Division of Endocrinology and Metabolism, Department of Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.|School of Medicine, Chung-Shan Medical University, Taichung, Taiwan.
authors.forename: I-Te
authors.initials: IT
authors.lastname: Lee
authors.affiliation: School of Medicine, National Yang Ming University, Taipei, Taiwan.|Division of Endocrinology and Metabolism, Department of Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Jun-Sing
authors.initials: JS
authors.lastname: Wang
keywords: Cardiac syndrome X (CSX); Coronary artery disease (CAD); Insulin resistance (IR); Metabolic health; Oral glucose tolerance test (OGTT)