Another area of study is the effect of confirmatory testing on the PA diagnostic cascade. This condition is responsible for 10% to 30% of hypertension cases globally. A new study led by Alexander A. Leung, MD, MPH, published in the Annals of Internal Medicine, reviews whether the commonly used seated saline suppression test (SSST) justifies its complexities in the diagnostic process.
Despite PA’s substantial burden, fewer than 1% of those affected are treated. This disturbingly low number is frequently the result of unawareness as well as the barriers posed by a confusing diagnostic journey. The research team aimed to clarify whether the additional steps involved in confirmatory testing contribute positively to patient outcomes or simply delay necessary care.
Concerns Over Diagnostic Pathways
The SSST is one of a number of confirmatory tests for PA that are now available in the United States. Other tests are the captopril challenge test and the fludrocortisone suppression test. Nonetheless, the SSST can still misguide treatment decisions and result in missed opportunities for timely intervention. When the researchers looked at the SSST’s ability to discriminate between positive and negative patient response statuses, they found it lacking.
“The SSST could not discriminate between response statuses (area under the curve, 62.1%; 95% CI, 45.1%-79.1%). The positive and negative likelihood ratios were equivocal for aldosterone cutoffs ranging from 140 to 300 pmol/L. These findings remained consistent after differences in treatment, occurrence of hypokalemia, and laboratory assay used were accounted for.” – authors (led by Alexander A. Leung, MD, MPH)
Based on these results, over one-third of patients suspected of having PA may not need a confirmatory test in practice. The research demonstrates that lifting the barrier of routine confirmatory testing can improve diagnostic accuracy. This advance reduces the time required for diagnosis and treatment in the majority of cases.
Limitations of the Seated Saline Suppression Test
The SSST involves a four hour saline intravenous infusion. This is an easier process to manage in an inpatient setting, but is a significant burden on outpatient facilities. This critical limitation calls into question just how effective it will be in the real world. This is of particular alarm for patients with poorly controlled hypertension or a history of CHF.
“For example, it is generally not used in patients with uncontrolled blood pressure or those with a history of congestive heart failure. Running an intravenous infusion of saline over 4 hours is easier in an inpatient setting but may be cumbersome in an outpatient office,” – Joshua D. Lenchus, DO, RPh
The study’s authors chose the SSST specifically because it is considered one of the most accurate confirmatory tests for PA. Their goal was to showcase its importance and effectiveness in their scientific research. Their findings conclude that its complexity doesn’t necessarily mean that it’s nuanced branches lead to better patient outcomes.
Implications for Future Diagnostic Practices
The research team stresses that their study’s results have the potential to change how healthcare providers diagnose PA. They continue to support a more expeditious, outcome-focused process that puts effective treatment responses ahead of wasteful confirmatory obstacles.
“We used response to targeted treatment as the reference because it is pragmatic and relevant to patients.” – authors (led by Alexander A. Leung, MD, MPH)
They further concluded that “the removal of routine confirmatory testing from the diagnostic care pathway for PA may help to improve diagnostic accuracy and reduce the time needed for diagnosis and treatment for most patients.”
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