Abstract
Objective To clarify whether it has some hidden diagnostic values for PA, especially in the case of an inconclusive SIT result, we investigated the difference in changes of plasma renin activity (PRA) during SIT between patients with PA and non-PA. Methods We measured and compared the SIT parameters of 159 PA patients, 368 non-PA patients, and 43 inconclusive patients who were included in this study. Results The PA group showed a minor change of PRA during the SIT (ΔPRA, defined as (pre-SIT PRA–post-SIT PRA)) compared with the non-PA group (0.17 ng/ml/h vs. 1.07 ng/ml/h, P < 0.001). According to ROC analysis, ΔPRA showed a greater AUC than post-SIT PRA (0.897 vs. 0.855, P < 0.001). The cutoff value was 0.5 ng/ml/h, with 90.3% sensitivity and 78.6% specificity. When combined with ARR post-SIT, it showed 81.6% sensitivity and 97.0% specificity for PA diagnosis. Further analysis of 43 patients with an inconclusive SIT result who completed AVS found that ΔPRA was smaller in the confirmed PA group compared with the unconfirmed PA group (0.19 ng/ml/h vs. 0.29 ng/ml/h, P < 0.05); there was no significant difference in PAC post-SIT between two groups. ΔPRA ≤ 0.21 ng/ml/h provides 71.4% sensitivity, 80.0% specificity, and 87.0% PPV for their PA diagnosis. Conclusions PA patients show minor PRA change during SIT; the change of PRA during SIT provides an auxiliary diagnostic value for PA, especially in patients with an inconclusive SIT result.
Highlights
Primary aldosteronism (PA), characterized by autonomous production of aldosterone and suppression of the renin, is a major cause of secondary hypertension accounting for up to 10%–15% of patients with hypertension [1,2,3]
Our results showed that patients who have a post-saline infusion test (SIT) aldosterone-to-renin ratio (ARR) more than 34 and ΔPRA less than 0.5 ng/ml/h should be confirmed as primary aldosteronism (PA) with +LR (21.2) and −LR (0.15), and of the 43 patients who were SIT indeterminate, the ΔPRA correctly diagnosed 21 patients as PA and 13 patients with essential hypertension (EH). us, 79.1% patients with inconclusive SIT results received a definitive diagnosis judging by ΔPRA
Compared with non-PA patients, plasma renin activity (PRA) postSIT was still lower, and plasma aldosterone concentration (PAC) post-SIT and ARR post-SIT were still higher in PA patients, which was consistent with other studies [23, 26,27,28]. ere was no difference in the PAC difference before and after SIT (ΔPAC) between the two groups, and the PRA difference before and after SIT (ΔPRA) in the PA group was lower than the non-PA group, which has not been reported before
Summary
Primary aldosteronism (PA), characterized by autonomous production of aldosterone and suppression of the renin, is a major cause of secondary hypertension accounting for up to 10%–15% of patients with hypertension [1,2,3]. For the detection of primary aldosteronism (PA), hypertensive patients are screened using the aldosterone-to-renin ratio (ARR). An elevated ratio requires confirmatory testing [10]. E saline infusion test (SIT) is the most commonly used confirmatory test recommended by the Endocrine Society guideline [10,11,12,13]. Suppression of plasma aldosterone concentration (PAC) after saline infusion is assumed to exclude PA. E Endocrine Society guideline suggests the use of two cutoff values: a post-SIT PAC >10 ng/dl confirms PA, whereas a post-SIT PAC 10 ng/dl confirms PA, whereas a post-SIT PAC
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