Feasibility of Screening Primary Aldosteronism by Aldosterone-to-Direct Renin Concentration Ratio Derived from Chemiluminescent Immunoassay Measurement: Diagnostic Accuracy and Cutoff Value.

Tianqi Li,Yinong Jiang,Yingchao Yang,Yeshuo Ma,Tingting Fu,Ri Zhang,Lixin Wang,Kai Kang,Yue Liu,Ying Zhang,Yan Lu

doi:10.1155/2019/2195796

Abstract

Objectives Aldosterone-to-plasma renin activity ratio (ARR) derived from traditional radioimmunoassay (RIA) is widely used to detect primary aldosteronism (PA). Recently, aldosterone-to-direct renin concentration ratio (ADRR), which is calculated by direct renin concentration (DRC) measured by chemiluminescent immunoassay (CLIA), is proposed to replace ARR as the screening test method for PA. The purpose of the present study was to estimate the diagnostic accuracy and cutoff value of ADRR as screening test for PA. Methods 450 hypertensive patients with suspected PA referred to hypertension center of our department were enrolled and underwent screening and confirmatory tests of PA. Plasma renin activity (PRA), DRC, and plasma aldosterone concentration (PAC) were measured by both RIA and CLIA simultaneously during screening and confirmatory test. Results 386 patients were diagnosed as primary hypertension (PH) and 64 patients as PA. Within-patient correlation between PRA and DRC (r=0.88, P<0.001) and correlation between PAC measured by RIA and CLIA were high (r=0.80, P<0.001). The optimal cutoff value of ADRR was 2.93 (ng/dL)/(mU/L), sensitivity 80.33%, and specificity 92.11%. The optimal cutoff value of ARR was 25.28 (ng/dL)/(ng/mL/h), sensitivity 76.92%, and specificity 93.38%. Conclusion The optimal cutoff values of ADRR and ARR for screening PA are defined in this patient cohort with high sensitivity and specificity. Our results are of clinical importance for accelerating the extensive use of ADRR as a screening test for PA in daily practice.

Highlights

Primary aldosteronism (PA) is characterized by excessive and autonomous aldosterone production and suppressed plasma renin and is commonly caused by aldosterone-producing adenoma (30%-50%) and bilateral adrenal hyperplasia (50%65%) [1, 2]
Since the treatment of patients with PA is different from that of patients with primary hypertension (PH), early diagnosis of PA is of clinical importance, which is essential for appropriate targeted management leading to prognosis improvement
Lower serum K+ accompanied by higher urinary K+, lower Plasma renin activity (PRA)/direct renin concentration (DRC), and higher plasma aldosterone concentration (PAC) (Table 3) was evidenced in PA patients

Summary

Introduction

Primary aldosteronism (PA) is characterized by excessive and autonomous aldosterone production and suppressed plasma renin and is commonly caused by aldosterone-producing adenoma (30%-50%) and bilateral adrenal hyperplasia (50%65%) [1, 2]. It is known that patients with PA are associated with significant higher risk of cardiovascular events and target organ damage than patients with primary hypertension (PH) at comparable blood pressure level [4, 6]. Since the treatment of patients with PA is different from that of patients with PH, early diagnosis of PA is of clinical importance, which is essential for appropriate targeted management leading to prognosis improvement. Up to 50% of hypertensive patients should undergo screening for PA, including hypertensive patients with grade 2-3 and resistant hypertension and hypertensive patients with hypokalemia independent of blood pressure levels [4, 7]

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