The diagnostic value of combined indexes in primary aldosteronism

Abstract

Objective To evaluate the value of plasma aldosterone concentration (PAC)/renin concentration (PRC) ratio (ARR) combined with aldosterone, renin, and sodium/potassium ratio in the diagnosis of primary aldosteronism (PA). Methods From January 2017 to October 2019, 105 patients were admitted to our hospital and diagnosed as PA and essential hypertension (EH) by clinical manifestations, laboratory examination and surgical pathological biopsy.The optimum cut-off point of ARR, PRC, PAC, plasma sodium-potassium ratio were determined by the Receiver Operating Characteristic (ROC). The sensitivity, specificity and Youden index at the optimum cut-off point were calculated in a separate test. By means of diagnostic test, the best cut-off points of ARR were tested in series with the best cut-off points of PRC, PAC and serum sodium/potassium ratio, respectively, and their specificity were calculated. Results The area under the AUC of supine ARR was greater than that of vertical ARR (0.966 vs 0.946, Z= 1.380, P= 0.168), but there was no statistical difference. The optimum cut-off point of supine ARR was 28.64(pg/ml)/(pg/ml), with a sensitivity of 92.4% and specificity of 90.5%. The sensitivity of the combined PRC test was 79.0% and the specificity was 94.3%. The sensitivity of the combined PAC test was 65.7% and the specificity was 95.2%. The sensitivity of the combined serum sodium/potassium ratio was 50.5% and the specificity was 96.2%. The optimal cut-off of vertical ARR was 22.10 (pg/ml)/(pg/ml), with 91.4% specificity and 85.7% specificity. The sensitivity of vertical ARR combined with PRC was 78.1%, specificity was 89.5%. The sensitivity of combined PAC was 74.3%, specificity was 92.4%, and the sensitivity of combined sodium/potassium ratio was 50.5%, specificity was 95.2%. Conclusions There was little difference in the diagnostic performance of PA between vertical and supine ARR values. The specificity of PA screening by ARR alone was high, and the specificity and accuracy of PA diagnosis could be improved by combining PRC, PAC and sodium/potassium ratio. Key words: Hyperaldosteronism; Aldosterone; Renin; Sodium; Potassium; Clinical laboraory techniques