Revaluation on the clinical value of saline infusion test in diagnosis of primary hyperaldosteronism

Objective　To evaluate the diagnostic value of saline infusion test (SIT) for patients with primary hyperaldosteronism (PA). Methods　The data of 132 patients with hypertension, admitted to the Department of Endocrinology of Chinese PLA General Hospital and undergone saline infusion test from Jan. 2014 to Mar. 2016, were retrospectively analyzed. Of the 132 subjects, 72 were with primary hyperaldosteronism (PA group) and 60 were with essential hypertension (EH group). The receiver operating characteristic (ROC) curve was drawn up based on the altered level of plasma aldosterone after infusion of saline and used to judge the suitable tangent point of PA diagnoses. Results　83.3% and 15.0% patients, respectively, in PA group and EH group were with the erect aldosterone-to-active renin ratio (ARR) ≥20. No significant difference existed in plasma aldosterone levels of patients between PA and EH group (ARR 0.05). Compared to the patients with erect ARR≥20 in EH group, those with erect ARRu003c20 in the same group had higher renin activity (Pu003c0.01) and lower blood sodium level (Pu003c0.05). After saline load, 91.7% and 75.0% patients, respectively, in PA group and EH group were with the plasma aldosterone levels greater than 10ng/dl. The optimal cut-off point for PA diagnoses was 388.1pmol/L (14.0ng/dl), the relevant area under the ROC curve (AUC) was 0.674, the sensitivity and specificity were 63.9% and 66.7%, respectively, and the Youden index (YI) was 0.3. Conclusions　SIT is a safe and reliable method for the diagnosis of PA. The best cut-off point of plasma aldosterone after saline loading is depended on recruited population and the diagnostic criteria. DOI: 10.11855/j.issn.0577-7402.2018.07.07