Objective: The aim of the study was to evaluate the changes in eGFR in patients with idiopathic primary aldosteronism (IHA) and with aldosterone-secreting adenoma (APA) after specific therapy. Design and method: From January 2018 to March 2022, we consecutively enrolled 99 patients with PA distinguishing 75 with IHA (mean age 53.41±11.97 years) and 24 with PA (average age 48.79±8.96 years). We evaluated anthropometric, biochemicals and hemodynamic parameters at diagnosis and 12 months after pharmacological or surgical therapy. Results: Patients with IHA, pharmacologically treated with mineralocorticoid receptor antagonists (MRAs), showed a higher incidence of chronic renal failure and a faster progression of renal damage than in patients with APA who underwent unilateral adrenalectomy. The reduction of eGFR was significantly greater in patients with IHA than in APA (92.03±17.58 vs 86.63±18.89 mL/min/1.73m 2 , p <0.001). Systolic blood pressure (SBP) levels and increased aldosterone-to-renin ratio were found to be independent predictors of renal function decline (ß = 0.034; p = 0.045 and ß = 0.248; p = 0.032, respectively). Conclusions: Our results show that patients with PA undergoing surgical treatment have a better renal outcome than those receiving drug therapy. An early diagnosis of APA would allow intervention before renal damage occurs.