Plasma Renin Activity (PRA) Levels and Antihypertensive Drug Use in a Large Healthcare System

Abstract

Although hypertension guidelines have utility in treating uncomplicated hypertension, they often overlook the pathophysiologic basis and heterogeneity of hypertension. This may explain the relatively poor hypertension control rates. A proposed approach is to guide addition and subtraction of medications using ambulatory plasma renin activity (PRA) values. To evaluate the heterogeneity of hypertension and the medication burden associated with it, we investigated medication usage in relation to PRA among hypertensive patients within a large ethnically diverse organization. A cross sectional data analysis was performed of hypertensive subjects with PRA measurements in the Kaiser Permanente Southern California database between 1 January 1998 and 31 October 2009. Among 7,887 such patients 0, 1, 2, ≥3 medication usage was 16%, 20%, 24%, 40% respectively. PRA levels ranged 1000-fold. Across PRA quartiles (Q1 to Q4) ≥3 meds were prescribed to 50%, 40%, 34%, 37%. From low to high PRA quartiles there was no usage trend for angiotensin converting enzyme inhibitors (ACEIs)/ angiotensin receptor blockers (ARBs) (71%), but diuretics increased (52%, 53%, 57%, 68%), calcium channel blocker's (CCB) fell (56%, 53%, 51%, 42%), and β-blockers fell (77%, 61%, 49%, 41%). Moreover, systolic BP fell (146, 142, 140, 135 mm Hg), blood urea nitrogen (BUN) rose (16, 17, 18, 20 mg/dl), serum uric acid rose (6.1, 6.3, 6.5, 6.9 mg/dl), and chronic kidney disease rose (22%, 22%, 23%, 27%). Polytherapy was the norm for treating hypertension. Lower PRAs were associated with higher blood pressures and more medications. Higher PRAs were associated with lower pressures and fewer medications. The results indicate that opportunities exist to simplify antihypertensive therapy by using current ambulatory PRA levels to guide drug selections and subtractions.