Prevalence of primary aldosteronism among hypertensive patients (preliminary results)
Joanna Matrozova, Sabina Zacharieva, Georgi Kirilov, Mihail Boyanov & Vladimir Hristov
Until recently primary aldosteronism /PA/ was thought to be rare, accounting for no more than 0.052% of the hypertensive patients. Studies published in the last decade demonstrate that primary hyperaldosteronism is a much more common cause of secondary hypertension than was previously thought, accounting for as many as 5% to 25% of hypertensives in some series. For the present, there are no data concerning the prevalence of PA in Bulgaria which determined the realization of the present study. A total of 200 patients/126 females, 74 males/were studied until now, including 160 patients, referred to the Clinical Center of Endocrinology and Gerontology, 20 patients referred to the Endocrinology Clinic, Internal Medicine Department, and 20 out-patients. The screening was effectuated using the aldosterone to renin ratio. Blood samples for aldosterone (pmol/l) and PRA (ng/ml/h) were taken under standardized sampling conditions and after correction of antihypertensive medications. We used 750 pmol/l/ng/ml/h as a cut-off for the ratio aldosterone/renin. The captopril test and the measurement of aldosterone in urine were used for confirmatory testing. The diagnosis of PA was confirmed in 13 cases, which suggests a prevalence of 6.5% among hypertensive patients. Adrenal tomography was performed in all biochemically confirmed cases of PA. The presence of different types of PA was as follows: 7 cases/54%/ of adrenal adenomas and 6 cases /46%/ of idiopathic PA. Among the confirmed cases of PA 1 normokalaemic and 12 hypokalaemic patients were found. Our study confirms the results obtained by other recent investigations for an increased prevalence of PA. In contrast to other studies in our research work the cases of Conns adenoma are predominant, as well as the hypokalaemic forms of PA.