Diagnostics of primary aldosteronism: is obligatory use of confirmatory tests justified?

INTRODUCTION: Assessment of the renin-angiotensin-aldosterone system has been recently granted a much greater role in the evaluation of patients with arterial hypertension. There is no single test efficient in selection of patients for second-step etiological investigation. METHODS: Altogether, 198 consecutive patients--119 women (60%) and 79 men (40%)--hospitalized in years 2009-2011 at the Clinical Department of Endocrinology Medical University of Bialystok were diagnosed with primary aldosteronism. In each patient, plasma renin activity and plasma aldosterone concentration (basic and after 2 l NaCl infusion) were evaluated. RESULTS: The percentage of patients with plasma aldosterone concentration ≥ 15 ng/ml was 53 and the percentage of patients with plasma renin activity ≤ 0.1 ng/ml/h was 20. The percentage of patients screened for primary aldosteronism in which the aldosterone:renin ratio exceeded consecutive cut-offs of 20, 30, 40 and 50 were respectively 57, 45, 34 and 29. Among 15 patients in which plasma aldosterone concentration after infusion of 2 l of saline was ≥ 6.5 ng/dl (8.6%), 13 (6.6%) were diagnosed with primary aldosteronism. CONCLUSION: The obligatory use of tests confirming autonomy of aldosterone secretion in patients screened for primary aldosteronism seems cost-effective in limiting the number of patients for further diagnosis.