ACE inhibitors and angiotensin receptor blockers (ARB) are considered cornerstones of anti-hypertensive therapy. These drugs modulate the renin-angiotensin system (RAS) leading to an increase in plasma renin activity (PRA) together with a reduction of plasma aldosterone concentration (PAC), proportional to the pharmacological effect. Aim: to evaluate the efficacy of stable therapies based on ACEI or ARB, using PRA / PAC ratio values in real-life clinical-practice.
Design and method:
We studied 184 essential hypertensives (59.2 ± 11.9 years, 63% males) in stable treatment for at least three months with an ACEI or ARB as part of the treatment. PRA was expressed as ng/ml and PAC as ng/dl, then the ratio was multiplied by 100. Tertiles of PRA/PAC ratio were considered for the analysis. ABPM was performed to evaluate the blood pressure (BP) control.
A significant linear correlation was present between the increase of PRA/PAC ratio and the reduction of BP values. Tertiles of PRA/PAC: 1st 0.2 to 5.7; 2nd 5.9 to 28.4; 3rd 29.4 to 509.8. There was no difference by age, sex, BMI and eGFR between PRA/PAC tertiles. A significant reduction in 24hour, daytime and night-time BP values was associated with increasing PRA/PAC tertiles (all p < 0.05). An increase of PRA/PAC tertiles was associated with a higher prevalence of controlled patients during the night-time period (1st: 14.5%; 2nd: 43.3%; 3rd: 45.9%; p < 0.001 for trend). PRA/PAC ratio was also a predictor of night-time BP control, as shown by ROC curve (AUC: 0.664, 95% CI: 0.582-0.745; p < 0.001).
An increasing PRA/PAC ratio reflects reduced values of PAC despite higher values of PRA as expression of a more effective RAS blockade by ACEI or ARB. These findings are associated with lower BP values and better BP control, especially in night-time period, highlighting the effectiveness and compliance to the anti-hypertensive therapy with ACEI or ARB. Therefore, PRA/PAC ratio may be not only a useful biomarker of effective treatment based on ACEI or ARB, but also can be used as indirect index of drug intake and therapy compliance.