Oral Virtual Presentation (Virtual only) ESA-SRB-ANZBMS 2021

The use of saline suppression test parameters to predict bilateral subtype of primary aldosteronism - an international multicentre study (#54)

Hikaru Hashimura 1 , Jinbo Hu 2 , Hiroki Kobayashi 3 , StellaMay Gwini 4 5 , Jimmy Shen 1 6 , Nicholas YN Chee 1 , James CG Doery 7 8 , Winston Chong 9 , Peter J Fuller 1 6 , Masanori Abe 3 , Qifu Li 2 , Jun Yang 1 6 10
  1. Endocrinology, Monash Health, Clayton
  2. Endocrinology, Affiliated Hospital of Chongqing Medical University, Chongqing, China
  3. Endocrinology, University Itabashi Hospital, Tokyo, Japan
  4. School of Public Health and Preventative Medicine, Monash University, Melbourne, VIC, Australia
  5. University Hospital Geelong, Barwon Health, Melbourne, VIC, Australia
  6. Centre of Endocrinology and Metabolism, Hudson institute of Medical Research, Melbourne, VIC, Australia
  7. Pathology, Monash Health, Clayton
  8. Medicine, Monash University, Melbourne, VIC, Australia
  9. Radiology, Monash Health, Clayton
  10. School of Clinical Sciences, Monash University, Melbourne, VIC, Australia

Background: The saline suppression test (SST) serves to confirm the diagnosis of primary aldosteronism (PA) while adrenal vein sampling (AVS) determines PA subtype. AVS however, is invasive, expensive and has limited availability. An accurate prediction of bilateral adrenal hyperplasia (BAH) based on SST could spare AVS in a significant cohort of patients. Our previous study suggested that a combination of plasma aldosterone concentration (PAC) <300 pmol/L and a reduced aldosterone-renin-ratio (ARR) following recumbent SST was 96.8% specific for predicting BAH in 121 patients [1].

Aim: To validate our criteria in an independent, international PA cohort, and to determine whether imaging characteristics, sex and potassium concentration might improve the accuracy of predicting BAH.

Methods: 289 patients were recruited (78 from Melbourne, Australia, 106 from Chongqing, China and 105 from Tokyo, Japan). Data including patient demographics, blood pressure, potassium supplementation and antihypertensive treatment; in addition to SST, adrenal imaging and AVS results were retrospectively analysed. Patients were subtyped based on AVS into unilateral aldosterone-producing adenoma (APA), BAH or indeterminate PA.

Results: At baseline, patients with BAH were more likely to be females with a lower PAC and higher serum potassium compared to those with APA in all cohorts. Following saline infusion, patients with BAH achieved a lower PAC compared to those with APA in all cohorts. Our criteria provided a specificity of 88.2%, 97.0% and 100.0% in the Australian, Chinese and Japanese cohorts respectively for predicting BAH. AVS could have been spared in 36.4%, 22.2% and 38.1% of BAH patients in the respective cohorts. Additional parameters including the absence of adrenal mass on CT, normokalaemia and female sex did not improve the predictive accuracy.

Conclusion: In recumbent SST, the criteria of PAC <300 pmol/L and a lower ARR post-saline are robust for predicting BAH in both Australian and Asian populations.

  1. 1. Hashimura H, et al. Saline suppression test parameters may predict bilateral subtypes of primary aldosteronism. Clin Endocrinol. 89(3):308-313,2018.