AIM: Plasma renin activity (PRA) is regarded as a marker of sodium and fluid homeostasis in patients with primary hypertension. Whether effects of diuretics on PRA differ according to class of diuretic, whether diuretics lead to a sustained increase in PRA, and whether changes in PRA relate to those in blood pressure (BP) is unknown. We performed a systematic review and meta-analysis of trials investigating the antihypertensive effects of diuretic therapy in which PRA and/or other biomarkers of fluid homeostasis were measured before and after treatment.
METHODS: Three databases were searched: MEDLINE, EMBASE and The Cochrane Central Register of Controlled Trials (CENTRAL). Titles were firstly screened by title and abstract for relevancy before full-text articles were assessed for eligibility according to a pre-defined inclusion/exclusion criteria.
RESULTS: A total of 1684 articles were retrieved of which 61 met the pre-specified inclusion/exclusion criteria. PRA was measured in 30/61 studies. Diuretics lead to a sustained increase in PRA which was similar for different classes of diuretic (standardised mean difference [95% CI] 0.481 [0.362, 0.601], 0.729 [0.181, 1.28], 0.541 [0.253, 0.830] and 0.548 [0.159, 0.937] for thiazide, loop, mineralocorticoid receptor antagonists/potassium-sparing and combination diuretics respectively, Q = 0.897, P = 0.826), nor to the decrease in BP.
CONCLUSION: In anti-hypertensive drug trials, diuretics lead to a sustained increase in average PRA which is similar across different classes of diuretic and is unrelated to the average reduction in BP.