Endocrine Abstracts

Objective: Withdrawal of the medications prior to screening for primary aldosteronism is problematic, sometimes impossible and probably not necessary as the routine practice. The aim of this study was to evaluate diagnostic accuracy of aldosterone-to-renin ratio in hypertensive patients undergoing laboratory screening for primary aldosteronism without obligatory drug modifications.

Methods: Plasma aldosterone and direct renin concentrations from 20 patients with primary hyperaldosteronism (group 1) and 80 controls (group 2) were measured and aldosterone-to-renin ratio was calculated. Patients were taking their usual antihypertensive drugs (one third was on 4 or more drug classes), excluding only mineralocorticoid receptor blockers. In the next step, necessary drug modifications were done and diagnostic process was carried on according to the current Endocrine Society guidelines.

Results: Group 1 and 2 were comparable in terms of age (57.5 vs 55.5 yrs, accordingly), BMI (28.18 vs 29 kg/m²), severity of hypertension (refractory hypertension in 25 vs 22.5%) the number of drugs taken (2 vs 2) and differ significantly in matters of the duration of hypertension (15 vs 7 yrs, P=0.03) and hypokalaemia (3.8 vs 4.24 mmol/l, P=0.0001). Aldosterone-to-renin ratio with the best cut-off level of 2.07 ng/dl/mIU/l was characterized by 95% sensitivity, 87.5% specificity and 89% accuracy (AUROC=0.94). With the cut-off level of 1.4 ng/dl/mIU/l the sensitivity of 100% was achieved.

Conclusions: The results of our work show that aldosterone-to-renin ratio serves as an accurate and reliable diagnostic tool despite antihypertensive therapy.