Hyperinsulinemia is alleged to contribute to the pathogenesis of hypertension and dyslipidemia (hypertriglyceridemia) in the setting of insulin resistance. To assess the association among hyperinsulinemia, hypertension, and hypertriglyceridemia in the absence of insulin resistance, we determined their prevalence in a large cohort of patients with insulinoma (N = 250). In this retrospective case-control study, patients with insulinoma were matched by age, gender, race, and year of operation with 217 control patients admitted to the hospital for elective cholecystectomy. Mean preoperative blood pressure measurements were compared between study patients and control patients. In addition, age-, gender-, and race-specific percentiles of blood pressure were compared with data from the National Health and Nutrition Examination Survey I, and those of triglycerides (N = 65) and cholesterol (N = 70) were compared with Mayo Clinic normal reference data. The study group consisted of 105 men and 145 women; the median age was 41 years (range, 8 to 82). The median duration of symptoms before operation was 1.9 years (range, 0.05 to 40 years). After adjustment for body mass index, no statistically significant differences in systolic and diastolic blood pressure were noted between patients with insulinoma and matched control patients (131 ± 19 versus 128 ± 18 mm Hg and 81 ± 11 versus 79 ± 9 mm Hg, respectively). No relationship was observed between duration of hyperinsulinemia (as long as 40 years) and blood pressure. The age- and gender-specific percentiles of systolic and diastolic blood pressure of the patients with insulinoma did not differ from the age- and gender-specific percentiles for the general white population. Furthermore, the prevalence of hypertension was similar for patients with insulinoma and matched control patients (34 versus 29%, respectively; P = 0.134) and did not exceed that expected for the general population. The age- and gender-specific percentiles of total plasma cholesterol concentrations among the patients with insulinoma were normal, whereas 21.5% of these patients had plasma triglyceride levels greater than the 95th age- and gender-specific percentile. Despite the increased triglyceride levels, no patient with insulinoma had a plasma triglyceride concentration that exceeded the criterion for hypertriglyceridemia—more than 250 mg/dl. We conclude that hyperinsulinemia, in the absence of insulin resistance, cannot be implicated in the genesis of hypertension or dyslipidemia.
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