Endocrine Abstracts (2017) 49 EP70 | DOI: 10.1530/endoabs.49.EP70

Abnormal aldosterone/renin ratio is common in patients of African compared to European origin, is associated with hypokalaemia, and left ventricular hypertrophy, but is rarely associated with abnormal adrenal imaging characteristics

KS Ahmed, D Bogdanet, S Heshe, G Boran, LA Behan, M Sherlock & J Gibney

Departments of Endocrinology, Cardiology and Chemical Pathology, The Adelaide and Meath Hospital, Incorporating the National Children’s Hospital, Tallaght, Dublin 24, Dublin, Ireland.

Adrenal mineralocorticoid biochemistry differs between people of African and European ancestry. The aldosterone/renin ratio (ARR) is the initial screening test for primary hyperaldosteronism (PHA), but little data exists regarding ethnic variations in this.

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 and intraventricular septal thickness (IVS, by echocardiography) were studied as end-points of PHA, and adrenal imaging was reviewed. Data were analysed using Student’s t-test, χ-square test and Mann–Whitney–Wilcoxon test as appropriate.

ARR was available in 1,473 patients, and abnormal in 374 (25.4%). Abnormal ARR occurred in 305/1473 (20.7%) of European and 69/124 (55.6%) of African 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 and 43/69 (62.3%) African patients. Median (range) IVS was 1.57(0.78–2.80) cm in African-origin and 1.2 (0.69–2.18) cm in European patients (P<0.002). Adrenal adenoma was identified in 2/69 (2.8%) African and 41/305 (13.4%) of European patients (P<0.005).

In summary, ARR was abnormal in 55.6% of African-origin patients screened at an Irish hospital, but only 2.8% had demonstrable adrenal pathology. Rates of hypokalaemia were similar between European-origin and African-origin patients, while cardiac hypertrophy was more marked in 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.

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