Objective: Left ventricular hypertrophy (LVH), an independent risk factor for cardiovascular (CV) morbidity and mortality, recognizes a multifactorial pathogenesis. A plasma glucose value ≥155 mg/dL for the 1-h postload plasma glucose during an oral glucose tolerance test (OGTT) identifies subjects with normal glucose tolerance (NGT) at high risk for type 2 diabetes. We addressed the question if glucose tolerance status, particularly 1-h postload plasma glucose levels, affects left ventricular mass (LVM) and cardiac geometry in essential hypertension.
Research design and methods: We enrolled 767 never-treated hypertensive subjects, 393 women and 374 men (mean age 49.6 ± 8.5 years). All patients underwent an OGTT for the evaluation of glucose tolerance and standard echocardiography. LVM was calculated using the Devereux formula and normalized by body surface area (LVM index [LVMI]). Insulin sensitivity was assessed by the Matsuda index. Among all participants, 514 had NGT, 168 had impaired glucose tolerance (IGT), and 85 had type 2 diabetes. According to the 1-h postload plasma glucose cutoff point of 155 mg/dL, we divided normotolerant subjects into two groups: NGT <155 mg/dL (n = 356) and NGT ≥155 mg/dL (n = 158).
Results: Subjects in the NGT ≥155 mg/dL group had worse insulin sensitivity than subjects in the NGT <155 mg/dL group (Matsuda index 63.9 vs. 88.8; P < 0.0001). Men with NGT ≥155 mg/dL had a higher LVMI than men with NGT <155 mg/dL (126.6 vs. 114.3 g/m(2); P = 0.002) and a different LVH prevalence (41.1 vs. 25.8%; P < 0.0001). At multiple regression analysis, 1-h glucose resulted in the major determinant of LVMI in normotolerant, IGT, and diabetic groups.
Conclusions: These data show that NGT ≥155 mg/dL subjects, compared with NGT <155 mg/dL subjects, have a higher LVMI and a greater prevalence of LVH similar to that of IGT and diabetic patients.