Confirmatory Tests for the Diagnosis of Primary Aldosteronism

Abstract

The diagnosis of primary aldosteronism typically requires at least one confirmatory test. The fludrocortisone suppression test is generally accepted as a reliable confirmatory test, but it is cumbersome. Evidence from accuracy studies of the saline infusion test (SIT) and the captopril challenge test (CCT) has provided conflicting results. This prospective study aimed to evaluate the diagnostic accuracy of the SIT and CCT using fludrocortisone suppression test as the reference standard. One hundred thirty-five patients diagnosed with primary aldosteronism and 101 patients diagnosed with essential hypertension who completed the 3 confirmatory tests were included for the diagnostic accuracy analysis. The areas under the receiver-operator characteristics curves of the CCT and SIT were 0.96 (95% confidence interval [CI], 0.92-0.98) and 0.96 (95% CI, 0.92-0.98), respectively, using post-test plasma aldosterone concentration (PAC) for diagnosis. However, the areas under the receiver-operator characteristics curves of the CCT decreased to 0.71 (95% CI, 0.65-0.77) when the PAC suppression percentage was used to diagnose primary aldosteronism. The optimal cutoff of PAC post-CCT was set at 11 ng/dL, resulting in a sensitivity of 0.90 (95% CI, 0.84-0.95) and a specificity of 0.90 (95% CI, 0.83-0.95), which were not significantly different from those of SIT (with PAC post-SIT set at 8 ng/dL, sensitivity: 0.85 [95% CI, 0.78-0.91], =0.192; specificity: 0.92 [95% CI, 0.85-0.97],=0.551). In conclusion, both CCT and SIT are accurate alternatives to the more complex fludrocortisone suppression test. Because CCT is safe and much easier to perform, it may serve as a more feasible alternative. When interpreting the results of CCT, PAC post-CCT is highly recommended.

Confirmatory tests for the diagnosis of primary aldosteronism: A systematic review and meta‐analysis

“…There is variability in the interpretation of CCT results. We therefore did a subgroup analysis of PAC post-CCT [13][14][15]17,19,24 and ARR post-CCT. 8,14,16,18,26,27 The…”

MANAGEMENT OF ENDOCRINE DISEASE: The role of confirmatory tests in the diagnosis of primary aldosteronism

“…SIT and FST. In the PAPY study, which provides a (46). In these studies, a high proportion of patients were hypokalemic (35,37,46,47).…”

“…In the PAPY study, which provides a (46). In these studies, a high proportion of patients were hypokalemic (35,37,46,47). The CCT has been criticized by European experts who emphasized a high rate of falsenegative or false-positive CCT in 36% of subjects from a small series of normokalemic PA patients (18).…”

“…These authors stressed the importance of sodium intake, which markedly affected the performance of the CCT when below 130 mEq per day, with CCT sensitivity dropping from 85.7 to 56% (36). In the CONPASS study, Song et al examined 135 Chinese hypertensive patients with PA and 101 patients with essential hypertension, both CCT and SIT exhibited high areas under the receiver-operator characteristics (ROC) curves at 0.96, 85-90% sensitivity and 90-92% specificity (46). Similarly, Meng et al found in 164 Chinese hypertensive patients, ROC areas under curve of 0.972 and 0.933 for post-SIT and post-CCT plasma aldosterone respectively (47).…”

Diagnostic approach to low‐renin hypertension

“…Normal range for plasma K + is 3.5-5.0 mmol/L [Colour figure can be viewed at wileyonlinelibrary.com] 14,19 The cumbersome FST is considered by some authors the gold-standard test, 22 but the CCT test and SIT, easier to perform, seem to be accurate alternatives. 14,23,24 However, a high rate of false negative results, when SIT is performed in the recumbent position, has been reported in patients with angiotensin II responsive forms of PA. 25 Similarly, in a larger cohort, 29% (12/41) of the patients with suppressed aldosterone levels after recumbent SIT (<139 pmol/L, 5 ng/dL) displayed a lateralized aldosterone production at adrenal vein sampling. 26 To rely only on the results of SIT would have excluded those patients from further diagnostic workup and potentially curative surgery.…”