RESUMO
BACKGROUND: Activity of the renin-angiotensin-aldosterone system is thought to play a major role in determining blood pressure (BP) and target organ damage such as left ventricular hypertrophy. In Afro-Caribbean subjects, however, hypertension tends to be more severe despite lower plasma renin activity. We investigated whether this might be due to a different relation between aldosterone and renin in Afro-Caribbean compared to white subjects. METHODS: Plasma aldosterone and renin activity were assessed in the morning after 15 min seated in 383 hypertensive subjects of Afro-Caribbean or white ethnicity (61% Afro-Caribbean, 83% on treatment) attending a hypertension clinic in London, UK. Left ventricular mass index (LVMI) was assessed by echocardiography in 276 subjects. RESULTS: Plasma renin activity was lower in Afro-Caribbean compared to white subjects (0.4 [0.3-1.0] v 1.4 [0.5-3.4] ng/mL/h, medians [interquartile range], P < .0001). Despite this, aldosterone was higher in Afro-Caribbean compared to white subjects (8.0 [6.1-12.6] v 7.4 [2.3-17.1] ng/dL, medians [interquartile range], P < .01). The LVMI corrected for sex and BP was higher in Afro-Caribbean than in white subjects. In Afro-Caribbean but not in white subjects LVMI was independently correlated with plasma aldosterone (standardized regression coefficient, beta= 0.25, P < .001). CONCLUSIONS: In Afro-Caribbean hypertensive subjects in London, plasma aldosterone is elevated despite lower renin and may contribute to increased severity of hypertension and left ventricular hypertrophy in Afro-Caribbean compared to white subjects.
