Feasibility of primary aldosteronism diagnosis in initial evaluation without medication withdrawal or confirmatory tests.

Purpose: Primary aldosteronism (PA), a frequent cause of hypertension, is highly associated with cardiovascular risk and mortality. PA diagnosis is often difficult due to the need to discontinue antihypertensive medication interfering with the renin-angiotensin-aldosterone system (I-RAAS). Our objective was to ascertain diagnosis of PA through biochemical assessments during screening while maintaining I-RAAS medications.

Methods: Hypertensive patients assessed for PA were involved. Patients were grouped according to the use of I-RAAS drugs during screening and the presence of PA. The diagnostic accuracy of the aldosterone-to-renin ratio (ARR), and other biochemical features were evaluated.

Results: 265 patients included, 122/265 with PA, and 192/265 were on I-RAAS therapy. The area under ROC curve (AUROC) of ARR for PA in patients without I-RAAS was 0.769 (95%CI: 0.66-0.877), and was 0.877 (95%CI: 0.828-0.926) in those with I-RAAS drugs. Sensitivity, specificity, positive predictive value, and negative predictive value (PPV) of cut-off of ARR > 50 were: 76%, 81%, 77.5%, and 79.6%. ARR > 50 plus hypokalemia had a PPV of 92.6% for PA. AUROC values of ARR evaluated in each group of antihypertensive drugs were >0.850 in all cases.

Conclusions: ARR during I-RAAS therapy demonstrates reliability and accuracy for PA diagnosis. An ARR > 50 combined with hypokalemia while on I-RAAS medication could be considered indicative of PA diagnosis.