Insulin resistance in men with treated hypertension at increased risk for cardiovascular disease: Results of a 3-year study

BACKGROUND: Insulin resistance is an independent risk factor for cardiovascular disease. The aim of this research was to establish the frequency of insulin resistance in a normoglycemic, hypertensive, male population to determine whether insulin resistance could be predicted by assessment of conventional risk factors and to assess the rate of deterioration. METHODS: Insulin resistance was calculated in hypertensive patients and healthy control subjects using a homeostasis model assessment for insulin resistance (HOMA-IR) and was correlated with routinely measured clinical variables. RESULTS: A total of 106 patients and 18 healthy control subjects were recruited. The healthy control subjects were similar to the patients in age and body mass index (BMI) but had a lower fasting glucose, insulin, and HOMA-IR. Of the patients, 36 were insulin sensitive (IS, HOMA-IR <1.5) and 21 were insulin resistant (IR, HOMA-IR >3.0). Mean blood pressure and type and number of antihypertensive medications did not differ between the groups. Compared with IS patients, IR patients were younger, had a higher BMI, higher triglycerides, and lower HDL, but there was substantial overlap of these risk factors between the groups. More IR than IS patients developed an impaired fasting glucose after 1 year (48% v 11%, P < .001). After 3 years of follow-up, 10% of the IR group and none from the IS group were confirmed as having type 2 diabetes mellitus. CONCLUSIONS: In this study, insulin resistance was common (20%) and could not be reliably diagnosed using conventional risk factors. One-half of the IR patients developed an impaired fasting glucose by 1 year, and, of these individuals, 20% were confirmed as having type 2 diabetes mellitus by 3 years.