Figure 1. Flow diagram of selecting study subjects.

(Abbreviations: MRA, mineralocorticoid receptor antagonist; PA, primary aldosteronism) *Our study only enrolled patients who ever used MRA (belonging to the ATC class C03D) in the one year prior to or the two years following the first ICD-9-CM coding of PA, because this additional condition could assure high values for both sensitivity and the positive predictive value according to our validated report¹⁷.