Comparison of different criteria of captopril challenge test for the diagnosis of primary aldosteronism.

Objectives: The Captopril Challenge Test (CCT) is favored in the diagnosis of primary aldosteronism (PA) for its simplicity and high patient compliance, yet optimal diagnostic criteria for CCT remain controversial. This study compared the accuracy of different CCT criteria for the diagnosis of PA.

Methods: This study included retrospective and prospective cohorts. High-risk PA patients were enrolled to complete aldosterone-to-renin ratio (ARR) screening, CCT, and the saline infusion test (SIT). SIT was used as the reference standard, and receiver operating characteristic (ROC) curves were constructed to evaluate the diagnostic accuracy.

Results: The retrospective cohort included 871 patients with PA and 464 with EH. The AUC for PAC post-CCT in diagnosing PA was 0.90, significantly higher than that of ARR post-CCT (0.73) or PAC suppression percentage (0.72). The prospective cohort included 134 patients with PA and 162 with EH, showing an AUC for PAC post-CCT of 0.89, significantly higher than that of ARR post-CCT (0.71) or PAC suppression percentage (0.58). Using a PAC post-CCT cutoff of 11 ng/dL for diagnosing PA achieved a sensitivity of 0.89 and specificity of 0.66 in the retrospective cohort, and a sensitivity of 0.77 and specificity of 0.84 in the prospective cohort, respectively.

Conclusion: PAC post-CCT served as a superior indicator for the diagnosis of PA, with 11 ng/dL recommended as the optimal diagnostic cutoff.