SYSTEMATIC HORMONAL SCREENING OF INCIDENTALLY DISCOVERED ADRENAL TUMORS YIELDS A HIGH DETECTION OF HYPERALDOSTERONISM

Abstract

Objective: The detection of adrenal incidentalomas is increasing. Current European guidelines suggest that all adrenal incidentalomas (AI) should be screened for excess cortisol and cathecolamines, but excess aldosterone only in the presence of hypertension and/or hypokalemia. Consistently, the reported prevalence of primary aldosteronism (PA), in AI is only 2–6%. The spectrum of primary aldosteronism has expanded to patients with mild hypertension and normokalemia, or even normotensives. Interestingly, even so-called “non-functioning” AI have been associated with future risk of hypertension. Screening by hypertensive status and diagnosis based on strict PA criteria suggest that current biochemical study is incomplete and/or insensitive to detect mild cases. To evaluate whether a systematic protocolized study can improve the detection of PA in adrenal incidentalomas.Design and method: We recruited a cohort of 226 adults with an adrenal incidentaloma, evaluated in our endocrinology clinic. We measured in all patients (hypertensives and normotensives) plasma aldosterone and renin with a protocolized approach: measurement in seated position, with unrestricted sodium intake, during follicular phase in premenopausal women and performing washout of confounding medications in selected cases. We defined a positive PA screening with suppressed renin in the setting of plasma aldosterone >6 ng/dL and aldosterone-renin ratio >20. We defined confirmed PA with either a positive confirmatory test or achievement of clinical and biochemical success criteria for PA treatment with adrenal surgery or aldosterone antagonists, as published by PASO study group. Results: Considering all subjects with AI, 17.25% (39/226) had a positive screening for PA and confirmed in 11% (25/226). These subjects had female predominance 68%, mean age 54 years, mean adenoma size 20 mm and did not differ from subjects with AI. Also, among confirmed cases 25% (5/25) were normotensive and 8% (2/25) had hypokalemia. Conclusions: Our study suggests that an important proportion of patients with PA are not currently being detected by usual clinical care of adrenal incidentalomas. Our protocolized study, including normotensive subjects and sensitive thresholds, improves diagnosis of milder cases. Since PA is associated with significant cardiovascular morbidity, earlier detection of the complete spectrum of this disease is clinically relevant.