PP.09.22

Abstract

Objective: Screening test is the first and crucial step of case detection for primary aldosteronism (PA), aldosterone/renin ratio (ARR) is currently regarded as the most reliable and available screening test for PA, however, the falling accuracy of ARR with increasing age has posed crucial challenge for PA screening among older-aged population.Design and method: To clarify potential effects of age on screening for PA, 216 subjects with PA and 657 subjects with non-PA were recruited and subdivided into four age groups (less than or equal to 39, 40–49, 50–59 and greater than or equal to 60 years). we respectively compared the level and tendency of PRA, PAC and ARR between different age groups and examined the accuracy as well as the best cutoff value of ARR as screening test for PA in each age group. Results: As expected, plasma renin activity (PRA) lowered more than plasma aldosterone concentration (PAC) and led to gradually elevated ARR with increasing age in the non-PA group (P < 0.001), whereas this phenomenon was unconspicuous in PA group. The best cutoff values of ARR for PA screening were elevated in subjects aged 50–59 years (28.0) and over 60 years (25.0) compared to subjects under 50 years (20.4), while the area under the receiver operating characteristic curves (AUCs), sensitivity, specificity, Youden's index (YI) and positive likelihood ratio (LR) of ARR were declined with increasing age, especially in patients over 60 years (AUC = 0.863, sensitivity = 95.2%, specificity = 69.0%, YI = 0.643 and LR = 3.1). The AUCs of PAC increased with increasing age and even slightly surpassed that of ARR in patients over 60 years (AUCPAC = 0.884). Conclusions: Our data suggest that the criteria of ARR for PA screening in patients over 50 years may need setting higher than in patients under 50 years; the falling accuracy of ARR with increasing age, especially in patients over 60 years, could be improved by taking into account the absolute value of the PAC when applicable by the center.