Confirmatory Testing for Primary Aldosteronism : A Study of Diagnostic Test Accuracy

Area of Science:

• Endocrinology
• Hypertension Research
• Diagnostic Test Accuracy Studies

Background:

• Confirmatory testing for primary aldosteronism (PA) after abnormal screening results has uncertain diagnostic value.
• Accurate diagnosis of PA is crucial for timely intervention and management of hypertension.
• The seated saline suppression test (SSST) is a commonly used confirmatory test for PA.

Purpose of the Study:

• To conduct a blinded assessment of the diagnostic accuracy of the SSST in patients with a positive PA screening result.
• To evaluate the SSST's ability to differentiate between PA responders and non-responders using treatment response as the reference standard.
• To determine the sensitivity, specificity, and predictive values of the SSST for PA diagnosis.

Main Methods:

• A diagnostic test accuracy study was conducted with 156 adults who had a positive PA screening result.
• The SSST involved administering 2 L of 0.9% sodium chloride intravenously over 4 hours while participants were seated.
• Treatment response, defined by blood pressure control and biochemical normalization, served as the reference standard for disease status.

Main Results:

• Post-SSST aldosterone levels showed significant overlap between treatment responders and non-responders (median 329 vs. 255 pmol/L).
• The SSST demonstrated poor discrimination between response statuses, with an area under the curve of 62.1%.
• Positive and negative likelihood ratios were equivocal across tested aldosterone cutoffs, indicating limited diagnostic utility.

Conclusions:

• The SSST is associated with a high false-negative rate, potentially leading to missed PA diagnoses.
• Relying solely on the SSST may result in delayed or missed opportunities for essential patient interventions.
• Further research is needed to identify more reliable confirmatory tests for primary aldosteronism.