Diagnostic Accuracy of Seated Saline Suppression Test for Primary Aldosteronism
Condition: Primary Aldosteronism
MeSH terms: Hyperaldosteronism
Study type: Observational

Summary: 
      The present study was undertaken prospectively to compare the diagnostic significance of the
      seated saline suppression testing (SSST) with the captopril challenge testing (CCT) in
      hypertensive patients with suspected primary aldosteronism (PA) using the fludrocortisone
      suppression testing (FST) as the reference standard, and to investigate the optimal cutoff of
      SSST for differentiating PA from other forms of hypertension.
    

Detailed description: 
      The diagnosis of primary aldosteronism (PA) typically requires at least one confirmatory
      test. Four tests are commonly recommended by the Endocrine Society guideline, namely, oral
      sodium loading, saline infusion, fludrocortisone administration with oral sodium loading, and
      captopril challenge testing (CCT). Of these, fludrocortisone suppression testing (FST) has
      been considered the most reliable, but is cumbersome, difficult to perform, and relatively
      expensive, requiring hospital admission for several days. Alternative approaches to FST have
      included saline suppression testing (SST), Which requiring patients staying in the recumbent
      position for at least 1 h before and during the infusion of 2 L of 0.9% saline IV over 4 h.
      This approach also has the disadvantages of brings much inconvenience to the patient (such as
      urination or defecation, etc.). Ashraf H. et al. have reported that seated SST (SSST) is more
      sensitive than recumbent SST (RSST), especially for posture-responsive PA (95.8% versus
      33.3%), however, in this small scale study, only 31 patients was PA and only three patients
      was tested negative for PA by FST. Specificity of each form of SST was unable to estimate and
      meaningful receiver operating characteristic (ROC) curve analyses could not be performed.
      Furthermore, it is lack of study in Chinese people. In addition, the investigators have
      previously found the CCT was as accurate as the FST and plasma aldosterone concentration
      (PAC) post-CCT is the best approach to interpret the results of the CCT. The present study
      was undertaken prospectively to compare the diagnostic significance of the SSST with the CCT
      in hypertensive patients with suspected PA using the FST as the reference standard, and to
      investigate the optimal cutoff of SSST for differentiating PA from other forms of
      hypertension.
    

Intervention name(s): Seated saline infusion test
Intervention type(s): Diagnostic Test
Intervention description(s): Seated saline infusion test: All participants received the infusion of 2 liters of 0.9% saline over 4 h in seated posture.
Fludrocortisone suppression test:Patients received 0.1 mg oral fludrocortisone every 6 h for 4 days, together with slow-release potassium chloride and sodium chloride supplements.
Captopril challenge test:Patients received 50 mg captopril orally at 8-9 a.m. after sitting or standing for at least 1 h. Blood samples were drawn at time zero and 2 h after the challenge.
Other intervention name(s): Captopril challenge test; Fludrocortisone suppression test
Intervention MeSH terms: Fludrocortisone; Captopril
Observational model: Case-Control
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Hospital or clinic patients with hypertension in a single tertiary hospital center.
      
Biospecimen description: 
      Serum, plasma and complete blood cell. Application: 1. diagnosis of PA and primary
      hypertension; 2.differential diagnosis of PA;
    
Keywords: Saline suppression testing, Seated, Recumbent