4.7-supplement.docx

Objective: Whether captopril challenge test (CCT) could be performed while taking interfering medications is unclear. This study aimed to investigate the diagnostic accuracy of CCT in primary aldosteronism (PA) while taking interfering medications.

Methods: This prospective study enrolled hypertensive patients to complete CCT while on and off interfering medications. Accuracy was assessed using area under the receiver operating characteristic curve (AUROC), referencing results of interfering medications.

Results: Finally, 341 hypertensive patients completed the study, including 219 essential hypertension (EH) and 122 PA. For all subjects, PAC pre- and post-CCT on interfering medications were 132.0 and 94.5 pg/ml, respectively, not significantly different from that off interfering medications [PAC pre-CCT 141.0, p=0.083; PAC post-CCT 91.2 pg/ml, p=0.559]. PRC pre- and post-CCT on interfering medications were 10.7 and 17.0 μIU/ml, respectively, higher than that off interfering medications [PRC pre-CCT 6.6 μIU/ml, p<0.001; PRC post-CCT 10.4μIU/ml, p<0.001]. However, the suppression rate of PAC (28.8% vs. 33.5%, p=0.542)] and increasing rate of PRC (45.7% vs. 47.9%, p=0.635) off interfering medications were not significantly different from that on interfering medications. AUROC of PAC post-CCT taking interfering medications was 0.83, and when the optimal cutoff of PAC post-CCT was set at 110 pg/ml, the sensitivity was 0.71 and the specificity was 0.82.

Conclusion: Using CCT to diagnose PA whilst taking interfering antihypertensive drugs is feasible in most cases.