Captopril suppression versus salt loading in confirming primary aldosteronism

Primary aldosteronism diagnosis requires biochemical confirmation. Standard methods include captopril suppression or salt loading. Prior research has shown that both approaches aim to assess aldosterone suppression. However, it was unclear whether these methods yield comparable results. No prior work had resolved whether captopril suppression could replace salt loading. This gap motivated a direct comparison of diagnostic accuracy. Researchers sought to determine if captopril testing could simplify diagnosis. They focused on plasma aldosterone responses under both conditions. The goal was to assess reliability and consistency of each method.

This study aimed to compare two diagnostic methods for primary aldosteronism. The objective was to evaluate if captopril suppression could match salt loading in accuracy. Researchers wanted to confirm if both approaches identify the same patient group. They focused on plasma aldosterone levels before and after interventions. The study targeted patients already suspected of having the condition. They aimed to assess reproducibility and correlation between methods. The goal was to determine if captopril testing could reduce diagnostic complexity. This would help streamline clinical workflows for diagnosing primary aldosteronism.

Researchers enrolled 49 patients suspected of primary aldosteronism. They performed captopril suppression tests in the morning. Blood samples were taken before and after captopril administration. Patients received 25 mg of captopril orally and remained seated. Plasma aldosterone levels were measured at baseline and 2 hours later. Following this, patients followed a high-sodium diet for three days. On day three, they collected 24-hour urine for sodium. Plasma aldosterone was measured at 8:00 AM and noon in both positions.

Of 49 patients, 44 showed nonsuppressible aldosterone levels. These patients exhibited classic clinical features of primary aldosteronism. Twenty-two had surgically confirmed adrenal adenomas. Twenty-two had presumed bilateral adrenal hyperplasia. Plasma aldosterone values after captopril correlated strongly with salt-loaded results (r=0.8, P<0.01). Distribution curves for aldosterone levels were similar between both tests. No significant difference was found between captopril and salt loading outcomes. Both methods identified the same patient group with high accuracy.

The study showed that captopril suppression testing is as effective as salt loading. Both methods produced comparable plasma aldosterone levels in patients. The correlation between the two approaches was strong and statistically significant. Researchers concluded that captopril testing could replace salt loading. This would simplify the diagnostic process for primary aldosteronism. The findings suggest that captopril suppression is a valid alternative. No prior work had resolved this equivalence in clinical practice. The results support using captopril suppression as a reliable diagnostic tool.