Incidence of Adrenal Masses Eventually Discovered in Patients Screened for Primary Aldosteronism

Context Biochemical screening for endocrine hypertension may be complex; the known presence of an adrenal mass markedly increases the pretest probability for adrenal hypertension and may inform diagnostic efforts. Objective Model the potential incidence of adrenal masses that may be detected by routine adrenal imaging in patients with suspected endocrine hypertension. Design Retrospective cohort study. Setting Provincial administrative and clinical databases for radiology and biochemistry, Alberta, Canada. Participants Patients with hypertension and any measurement of aldosterone-renin ratio (ARR), 2012 to 2019. Main Measures Radiology report of any computed tomography or magnetic resonance imaging abdomen performed for any reason 0 to 12 years following ARR. Patients with any pre-ARR imaging data between 2002 and 2024 were excluded. The presence of adrenal mass, size, and density were recorded and stratified by imaging indication. Results Of 6942 unique hypertension patients with ARR, 1462 (21%) had imaging done at some point after ARR, 912 (62.4%) for indications unrelated to hypertension/adrenal and at a median 771 days (69-1577) post ARR. The incidence rate estimate was 7.2% (5.6-9.2%) of scans showed adrenal mass, median 1.4 cm (1.1-2.3), a rate well above the modern series of adrenal incidentaloma prevalence in unselected adults. The number needed to screen in this population was 14 (11-18) to detect an adrenal mass without a priori indication for adrenal imaging. Conclusion Among patients screened for PA but without prior or subsequent directed adrenal imaging, 1 in 14 were later found to have an adrenal mass on imaging done for other indications. Given the impact on pretest probability for endocrine hypertension and further investigation steps, routine adrenal imaging might be considered whenever PA suspicion is high.