Endocrine Abstracts

JOINT2502

Background: Primary aldosteronism (PA) is the most prevalent cause of secondary hypertension. The prevalence of PA is high and often overlooked using current diagnostic approaches. Screening for the disease involves measuring the aldosterone–renin ratio (ARR). Aldosterone secretion is pulsatile and variable. PA also exhibits intraindividual variability in aldosterone concentrations. The 24-hour urine aldosterone levels are unaffected by diurnal and pulsatile changes in plasma aldosterone levels. Complications can occur during the confirmatory tests. The diagnosis of primary aldosteronism requires new approaches. This study used 24-hour urine aldosterone with suppressed renin activity to compare classical confirmatory methods.

Methods: The study included twenty-one patients with suspected primary aldosteronism. After correcting the patients’ hypokalemia and bringing their hypertension under control, we collected 24-hour urine before proceeding with other confirmatory tests. We applied classical confirmatory tests like saline infusion (n=20) and the captopril test (n=1) to the patients. We did not perform an oral salt loading test on the patients. Plasma renin activity of all patients was below 1 ng/ml/h. Patients were divided into three groups according to 24-hour urine aldosterone levels: group 1 (<6 mcg/24 h), group 2 (6–12 mcg/24 h), and group 3 (>12 mcg/24 h).

Results: Mean 24-hour urine aldosterone levels were 4.03 mcg/24 h in group 1, 8.32 mcg/24 h in group 2, and 23.36 mcg/24 h in group 3 (P < 0.001), respectively. Classical confirmatory tests excluded PA in 10 patients. In groups 1 and 2, there were no patients with hypokalemia. In Group 3, all patients were hypokalemic. In group 1, standard confirmatory tests ruled out PA. There was no need for further workup of PA for patients in group 2. All patients in this group received antihypertensive agents during the follow-up, and no adrenal venous sampling or surgery was required. All patients in group 3 received confirmation of their PA diagnosis. Adrenal venous sampling was performed in 5 patients, and five underwent surgery in this group.

Conclusions: PA is a disease that can result in significant cardiovascular morbidity and mortality. Early and accurate diagnosis of the disease is crucial. We have demonstrated that 24-hour urine aldosterone with suppressed plasma renin activity measurements is an alternative and more practical diagnostic method than other classical confirmatory methods. It can help avoid complications of classical confirmatory tests and help achieve diagnosis and treatment more accurately and in a shorter time.