Rates of Abnormal Aldosterone/ Renin ratio in African-origin compared to European-origin patients; a retrospective study.

INTRODUCTION: The aldosterone/ renin ratio is the initial screening test for primary hyperaldosteronism (PHA), but little data exists regarding ethnic variations in this.

METHODS: Following clinical observation of a high prevalence of abnormal ARR in patients of African origin, we retrospectively reviewed all ARR measurements in a single centre over 10 years. Rates of hypokalaemia, intraventricular septal thickness (IVS, by echocardiography) and adrenal imaging were recorded when available.

RESULTS: ARR was available in 1473 patients, and abnormal in 374 (25.4%). Abnormal ARR was observed in 305/ 1349 (22.6%) of European-origin and 69/ 124 (55.6%) of African-origin patients (p<0.001). Among those with abnormal ARR, hypokalaemia (<3.5 mmol/l) was documented on at least one occasion in 171/ 305 (56.1%) European-origin and 43/ 69 (62.3%) African-origin patients (p=0.35). Median (range) IVS was 1.57 (0.78 - 2.80) cm in African-origin and 1.20 (0.69 - 2.18) cm in European-origin patients (p<0.002); IVS did not correlate with aldosterone or ARR however. Adrenal adenoma was identified in 41/170 (24.1%) of European-origin and 4/29 (13.7%) African-origin patients (p=0.15), while hyperplasia was identified in 35/170 (20.5%) of European and 8/29 (27.5%) African patients (p=0.39).

CONCLUSION: In summary, ARR was abnormal in 55.6% of African-origin patients screened at an Irish hospital. Rates of hypokalaemia were similar between European-origin and African-origin patients. These findings have implications for the use of current screening guidelines for ARR in African-origin patients and also for the mechanistic role of aldosterone in hypertensive complications in African-origin patients. This article is protected by copyright. All rights reserved.