Context: Patients with hypertension have a high prevalence of concurrent metabolic abnormalities, including obesity, dyslipidemia, and hyperglycemia. Clustering of these cardiovascular risk factors, defined as metabolic syndrome, causes a more pronounced target organ damage. Aldosterone excess has been found to be associated with glucose disorders and may contribute to cardiovascular damage.

Objective: The aim of our study was to assess the prevalence and the characteristics of the metabolic syndrome in a group of patients with hypertension due to primary aldosteronism compared with patients with essential hypertension.

Methods: The National Cholesterol Education Program Adult Treatment Panel III definition of the metabolic syndrome was used. Eighty-five patients with primary aldosteronism and 381 patients with essential hypertension were studied. Most patients were not receiving antihypertensive therapy during the investigation.

Results: Blood glucose and systolic blood pressure were higher (P < 0.05 and P < 0.01, respectively) and duration of hypertension was longer (P < 0.05) in primary aldosteronism than in essential hypertension. The prevalence of metabolic syndrome was higher in primary aldosteronism than in essential hypertension (41.1% vs. 29.6%; P < 0.05). Distribution of single components of the metabolic syndrome other than hypertension showed a higher prevalence of hyperglycemia in primary aldosteronism than in essential hypertension (27.0% vs. 15.2%; P < 0.05).

Conclusions: Our findings confirm a negative effect of aldosterone excess on glucose metabolism and suggest that the recently reported higher rates of cardiovascular events in primary aldosteronism than in essential hypertension might be due to increased prevalence of the metabolic syndrome in the former condition.