Identifying unilateral disease in Chinese patients with primary aldosteronism by using a modified prediction score

OBJECTIVE: The current study aimed to evaluate the role of Küpers’ score in predicting unilateral aldosteronism, and develop a modified score in Chinese patients with primary aldosteronism. METHODS: The current retrospective study included 406 patients with primary aldosteronism who underwent successful adrenal venous sampling (AVS) and were divided into the unilateral (n = 211) and bilateral (n = 195) groups according to the AVS results. Normokalemia was noted in both the unilateral (n = 64) and bilateral groups (n = 84) when plasma and urinary aldosterone were measured. RESULTS: We evaluated Küpers’ prediction score, which had the best cutoff value at four points [area under the curve, 0.601 (95% confidence interval 0.551–0.650); specificity, 53%; sensitivity, 62%]. Then, we modified this score by using urinary aldosterone level quartiles, history of hypokalemia, and typical adenoma more than 10 mm on computed tomography (CT) [area under the curve, 0.745 (95% confidence interval 0.667–0.813)]; sensitivity, 45.3%; specificity, 90.5%). The best cutoff value to discriminate unilateral from bilateral disease was a score of 5. This modified prediction score only applied to patients who were normokalemic when urinary aldosterone was measured. A specificity of 100% was achieved at a score of 6 for patients aged 40 years or less, and 5 when the adrenal lesion was on the right side on CT imaging. CONCLUSION: Küpers’ prediction score is not suitable for our patients. Urinary aldosterone levels combined with a history of hypokalemia are useful to discriminate unilateral from bilateral aldosteronism in patients with typical adenoma on the right adrenal gland on CT or in patients 40 years old or less.