Immediate Postoperative Decrease in Serum Potassium and One-Month Reduction in Renal Function after Adrenalectomy for Primary Aldosteronism: A Multicenter Retrospective Study

Objectives: Although adrenalectomy for primary aldosteronism (PA) corrects hypokalemia, we observed cases in which serum potassium decreased immediately after adrenalectomy, even in patients with preoperative hypokalemia. No studies have described postoperative potassium changes in PA. In contrast, recent reports have described renal function decline 1 month after adrenalectomy in PA; however, the evidence remains limited. Therefore, we aimed to clarify whether postoperative decreases in serum potassium and renal function occur in PA. Methods: We retrospectively reviewed perioperative data from patients with PA or nonfunctional adrenal tumors (NF) who underwent laparoscopic adrenalectomy between 2006 and 2023 to assess postoperative changes in serum potassium levels and estimated glomerular filtration rate (eGFR). Results: A total of 161 patients were included. The mean changes in serum potassium on postoperative Day 0 were -0.36 +/- 0.44 and -0.20 +/- 0.46 mEq/L in the PA and NF groups, respectively (p = 0.034). Multivariable regression analysis revealed that PA (p < 0.001), preoperative serum potassium levels (p < 0.001), and plasma aldosterone concentration (PAC) (p = 0.004) were associated with potassium decrease, whereas preoperative use of mineralocorticoid receptor antagonists (MRAs) attenuated this decrease (p < 0.001). The mean changes in eGFR 1 month after adrenalectomy were -10.02 +/- 12.62 and 0.44 +/- 9.63 mL/min/1.73 m(2) in the PA and NF groups, respectively (p < 0.001). Multivariable regression analysis identified age (p = 0.029), male sex (p = 0.009), PA (p = 0.009), preoperative eGFR (p < 0.001), and PAC (p = 0.006) as factors associated with eGFR decline. Conclusion: This study demonstrates that serum potassium may decrease immediately after adrenalectomy, and preoperative use of MRAs may mitigate this decrease. It also shows that renal function may decline 1 month after adrenalectomy. Patients with higher preoperative PAC may warrant closer monitoring, as elevated PAC is associated with greater postoperative decreases in potassium and eGFR.