Abstract P136: Reference Ranges And Cut-Off Values For Simultaneous Monitoring Of RAS-Blocker Efficacy And Screening For Secondary Hypertension Using RAAS Triple-A Profiling

Abstract

Uncontrolled hypertension is caused by various factors including compliance issues, patient specific drug uptake and elimination profiles or secondary forms of hypertension, resulting in blood pressure control rates of less that 50%. RAAS Triple-A profiling is a high-throughput mass-spectrometry based assay for Angiotensin I (Ang I), Angiotensin II (Ang II) and Aldosterone in serum samples. Hormone levels are used to calculate markers for plasma-renin-activity (PRA-S), plasma angiotensin-converting-enzyme activity (ACE-S) and adrenal aldosterone secretion (AA2-Ratio). The integrated analysis of these molecular markers together with drug prescription information allows to identify the underlying cause of uncontrolled hypertension, including primary aldosteronism and insufficiency in drug adherence or dosing for ACE inhibitors (ACEi) and angiotensin receptor blockers (ARBs). 500 participants with prescribed antihypertensive drugs were selected from the “Cooperative Health Research in South Tyrol” (CHRIS) study, a population-based study from an Alpine rural environment. Five age- and sex-matched groups (N=100 each) selected were individuals on single therapy with ARBs, ACEi or beta blockers, and on single pill dual therapy of ACEi or ARBs in combination with diuretics. Three age and sex-matched control groups of 100 participants each were included, being normotensive, hypertensive (treated with non-antihypertensive drugs) and hypertensive participants without any prescribed medication. RAAS Triple-A analysis was performed in all individuals and reference values for Ang I, Ang II, Aldosterone, PRA-S, ACE-S and AA2-Ratio were established in appropriate sub-populations. Drug monitoring by LC-MS/MS based quantification of anti-hypertensive drugs in serum was used as a gold standard to determine cut-off values for compliance with ARB and ACEi therapy and ROC analysis was performed using angiotensin-based biomarkers.