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.