Clinical and biochemical outcomes after adrenalectomy and medical treatment in patients with unilateral primary aldosteronism

Objectives: Current clinical guidelines of primary aldosteronism recommend adrenalectomy (AdX) for unilateral primary aldosteronism based on the studies showing the potential superiority of AdX over the medical treatment. However, since most medically treated cases consisted of bilateral primary aldosteronism and all surgically treated cases consisted of unilateral primary aldosteronism, the different subtype of primary aldosteronism could be a bias for their effects. This study compared the effects of AdX and medical therapy in patients with unilateral primary aldosteronism confirmed by adrenal vein sampling. Methods: Of the 339 patients with unilateral primary aldosteronism in the Japan Primary Pldosteronism Study data base, unilateral AdX and treatment with mineral corticoid receptor antagonists (MRAs) was done in 276 patients (AdX group) and in 63 patients (MRAs group), respectively. The effects were compared by the clinical (improvement of blood pressure) and biochemical outcomes (improvement of hypokalemia). Results: At baseline, use of potassium replacement, plasma aldosterone concentration, aldosterone-to-renin ratio, estimated glomerular filtration rate, and prevalence of adrenal mass on imaging were higher in the AdX group than in the MRAs group. At 6 months after commencement of specific treatment for primary aldosteronism, clinical outcome and biochemical outcome in the AdX group were superior than those in the MRAs group. The difference of the outcome between the two groups were the case even after adjusting for the different clinical backgrounds in the two groups before the specific treatment. Conclusion: Our study provides evidence that AdX is the first choice of treatment in the patients with unilateral primary aldosteronism in terms of clinical and biochemical outcome.