SAT-060 Analysis of over 24,000 Aldosterone to Renin Ratio for Screening Hypertensive Patients for Primary Aldosteronism

Primary aldosteronism remains an underdiagnosed and undertreated endocrine disease(2). More than 100 million adults in the USA are hypertensive, and 5% or more of the cases may be related to primary aldosteronism. The value of primary aldosteronism diagnosis is to guide surgical or medical treatment. Aldosterone to Renin Ratio (ARR) is the screening tool designated by the Endocrine Society’s 2016 guideline(1) aimed at screening hypertensive patients for primary aldosteronism. Used properly, the test has a high negative predictive value and a moderate positive predictive value(2). 24,508 ARR results were surveyed to determine the positivity rate for the ARR screen. Various cancellations eliminated 1592 results, and 20,656 results were valid. The frequency of ARR results greater than 30 was 8.75%. In addition, another 1.11% of results had undetectable renin values with aldosterone values greater than 20 ng/dL, thus these were designated as screen positives. The total frequency of screen positivity was 9.86%. A secondary study goal was to investigate available characteristics of the ARR positive screen patients. The median age of the positive ARR screen patients (57) was not significantly different from the age of all patients screened (56). The percent female was only slightly lower in the positive ARR group than in the negatives (57% vs 54%). High ARR patients had low potassium -with a frequency of 11.5%. The most common ICD10 codes in the screen positive patients were for primary hypertension (20.9% of all samples but 52.9% of positives), followed by hypokalemia (3.7% of all samples but 9.5% of positives), disorder of the adrenal gland (1.8% of all samples but 4.6% of positives). Chronic kidney disease due to hypertension was also found more frequently in positive ARR patients. In addition, many other codes at less than 1%, including vitamin D deficiency, hyperlipidemia, and hypothyroidism were found less frequently in ARR positive than in negative patients. Conclusions: The ratio of two routine blood tests, aldosterone to renin may have large implications for the hypertensive patient because high blood pressure due to primary aldosteronism may be better controlled medically or surgically with appropriate diagnosis. The positive screen rate in a large series of patient screens was about 10%. The Medicare cost of ARR screening is less than $80.00, and the reasonable cost underscores cost-effective ARR test utilization for screening hypertensive patients. References: (1)The Management of Primary Aldosteronism: Case Detection, Diagnosis, and Treatment An Endocrine Society Clinical Practice Guideline. J Clin Endo Metab 2016; 101(5): 1889-1916. (2)Buffolo F, Monticone S, et al Is Primary Aldosteronism Still Largely Unrecognized? Horm Metab Res. 2017 Dec;49(12):908-914.