Endocrine Abstracts

Introduction: Primary hyperaldosteronism (PHA) is the most common hormonal cause of hypertension concerning about 5–12% of hypertensive individuals. Aldosterone to renin ratio (ARR) and 24 h urine aldosterone concentration (24-UAC) are important tools in PHA screening diagnostics. The most appropriate cutt off values predicting PHA are still being discussed. The study is to assess siutability and to determine optimal cut off values of ARR and 24-UAC for accurate PHA prediction in uniform hypertensive population.

Methods: Fifty-nine hypertensive patients (age 49.20, S.D.: ± 14.45) with clinical suspicion of PHA, following a normal salty diet underwent 24 h-urine aldosterone concentration collection and ARR measurement after 2 h of verticalization. The verification of PHA diagnosis was based on the serum aldosterone concentration after the 0.9%NaCl loading test. Statistical analysis was performed. Evaluation of the test accuracy was performed based on the receiver operating characteristic (ROC) curve analysis.

Results: According to the salt loading test PHA was confirmed in 30 patients, and in 29 essential hypertension was diagnosed. The calculated sensitivity of ARR value >20, >30, >40 was respectively 100%, 92.59%, 85.19% for PHA prediction, while the specificity of ARR value >20, >30, >40 was respectively 44.44%, 66.67%, 74.07%. The calculated sensitivity of 24UAC >10, >12, >15, >17 µg/24 h for PHA prediction was respectively 73.91% 73.91% 68.18% 65.22% and the specificity was 69.23%, 76.92%, 85.71%, 92.31% respectively.

Conclusion: The results suggest that (1) the most appropriate ARR and 24-UAC cut off values consistent with the possibility of PHA confirmation are: ARR >40 and 24-UAC>15 µg/24 h in homogenous hypertensive population.