Diagnostic rate of primary aldosteronism in Emilia-Romagna, Northern Italy, during 16 years (2000-2015)

Although primary aldosteronism is considered the most common form of endocrine hypertension, the diagnostic rate of primary aldosteronism in the territory is unknown.

The aims of the current study were to compare the number of patients discharged with International Classification of Diseases 9 Clinical Modification codes compatible with primary aldosteronism from all the hospitals in Emilia-Romagna during 16 years (from 2000 to 2015) with the number of expected cases of primary aldosteronism, and to compare the number of patients with primary aldosteronism who underwent adrenalectomy in the period 2000-2015 with the number of expected cases of unilateral primary aldosteronism.

We accessed the Database of the Emilia-Romagna Health Service to select all patients from the age of 20 years discharged with International Classification of Diseases 9 Clinical Modification codes compatible with primary aldosteronism and, among them, those who underwent adrenalectomy in the same period. The prevalence of hypertension in Emilia-Romagna from the age of 20 years was drawn from the Health Search Database. The population from the age of 20 years in Emilia-Romagna has been drawn from the Italian National Statistical Institute. We hypothesized a prevalence of primary aldosteronism of 5% among hypertensive patients and a prevalence of unilateral subtypes of 30% among the primary aldosteronism patients.

A total of 992 patients have been discharged with codes consistent with primary aldosteronism during 16 years in Emilia-Romagna, that is 1.9% of the expected cases of primary aldosteronism. A total of 160 of them underwent adrenalectomy in the same period, which corresponds to 1% of the expected cases of unilateral primary aldosteronism in Emilia-Romagna.

Our results clearly indicate that primary aldosteronism is dramatically underdiagnosed and undertreated.