Screening for primary aldosteronism on and off interfering medications

Objective: To determine whether antihypertensives will affect diagnostic accuracy of the aldosterone-to-renin ratio (ARR) to an extent that is clinically relevant.

Methods: Confirmatory tests were used to confirm or exclude PA diagnosis. Area under the receiver operating characteristic curve (AUC), specificity and sensitivity of ARR performance in different conditions were calculated.

Results: 208 PA and 78 essential hypertension (EH), and 125 PA and 206 EH patients, were included in the retrospective and prospective cohort, respectively. AUC of ARR on interfering medications was comparable to ARR off interfering medications (retrospective: 0.82 vs. 0.87, p = 0.20; prospective: 0.78 vs. 0.84, p = 0.07). At a threshold of 20 pg/μIU, the sensitivity of ARR on interfering medications was lower (11.1-23.2%) while the specificity was higher (10.2-15.2%) than ARR off interfering medications. However, when the ARR threshold on interfering medications was lowered to 10 pg/μIU, both the sensitivity (retrospective: 0.91 vs. 0.90, p = 0.61; prospective: 0.86 vs. 0.82, p = 0.39) and specificity (retrospective: 0.49 vs. 0.59, p = 0.20; prospective: 0.58 vs. 0.66, p = 0.10) were comparable to the ARR threshold off interfering medications.

Conclusion: Using ARR to screen for PA whilst taking interfering antihypertensive drugs is feasible in most cases, but the ARR threshold needs to be reduced.

Trial registration: ClinicalTrials.gov identifier: NCT04991961.