Clinical relevance of dietary salt intake on aldosterone and the aldosterone-to-renin ratio as screening parameters for primary aldosteronism.

AIMS: The recommendations for screening for primary aldosteronism (PA) are determination and interpretation of both plasma aldosterone and the aldosterone-renin ratio (ARR). Although it is known that oral sodium chloride intake has an important impact on plasma aldosterone and ARR, more detailed data of this impact are sparse. We evaluated the relevance of natriuresis as a parameter of oral sodium intake, as well as patient age and antihypertensive medication on the PA screening parameters in our hypertensive patient population.

METHOD: Our cross-sectional, single-center study investigated the impact of natriuresis, patient age, body mass index, Ca-antagonists, beta-blockers, ACE inhibitors and/or AT1 blockers on aldosterone and ARR in 777 hypertensive patients (393 men, 384 women) with a mean age (± SD) of 49.5 ± 15.7 years and an endogenous creatinine clearance of at least 80 ml/min. A total of 401 patients (51.6%) were on antihypertensive therapy. The mean natriuresis of the total population was 206.7 ± 97.0 mmol/day. The potential impact factors on plasma aldosterone and ARR were analyzed in two separate univariate, bivariate, and multiple regression analyses, respectively, with natriuresis as the main impact factor.

RESULTS: Natriuresis as well as patient age had a significant impact on both plasma aldosterone and ARR. In addition, beta-blockers, ACE inhibitors and/or AT1 blockers had a significant impact on ARR (p < 0.05).

CONCLUSIONS: In addition to antihypertensive medication, natriuresis as well as patient age seem to need further consideration in the process of PA screening and interpretation of its results. Additional experimental studies are warranted to confirm and generalize our results.