Age Below 40 or a Recently Proposed Clinical Prediction Score Cannot Bypass Adrenal Venous Sampling in Primary Aldosteronism

Context: Adrenal venous sampling (AVS) is used to distinguish bilateral from unilateral primary aldosteronism (PA). Due to its limited availability, clinical prediction scores have been proposed to diagnose unilateral disease without AVS. Objective: Our goal was to test 2 recently proposed predictors of unilateral PA: 1) a clinical prediction score using imaging, serum potassium, and glomerular filtration rate and 2) the combination of visible unilateral adenoma on imaging and age <40 years. Design and Setting: We used the data of all patients with PA of the prospective German Conn's Registry treated in Munich and Berlin since 2008. Patients and Intervention: Of 205 patients with PA, 194 had a successful AVS and were included. Main Outcome Measures: Parameters were compared between patients with lateralized and nonlateralized AVS. Specificity and sensitivity of the proposed predictors were calculated. Results: A total of 130 patients (67%) had unilateral PA according to AVS. Patients with unilateral PA showed a significantly lower estimated glomerular filtration rate compared with patients with bilateral disease (P<.05). The cohorts differed significantly in potassium supplementation, serum potassium, baseline and post-saline plasma aldosterone, baseline aldosterone to renin ratio, and adenoma in imaging. The proposed prediction score had a sensitivity of 46% (58 of 127) and a specificity of 80% (53 of 66). In patients below 40 years (n = 28), the prediction score achieved a specificity of 100%; however, relying only on imaging in this young cohort, the specificity dropped to 83%. Conclusions: The suggested prediction score has high accuracy only in young patients but cannot substitute for AVS in the elderly.