Glomerular filtration rate (GFR) has been reported to decrease after unilateral adrenalectomy in patients with primary aldosteronism (PA). The aim of this study was to identify clinical predictors for decreased GFR after adrenalectomy in patients with PA. The records of 187 patients (98 patients with PA and 89 with non-PA adrenal disease) who were followed up for at least 6 months after unilateral adrenalectomy were retrospectively analyzed. Estimated GFR (eGFR) was investigated at 1, 3, and 6 months postoperatively. Preoperative risk factors for eGFR% decline at 1 month ([preoperative eGFR-eGFR at 1 month]/preoperative eGFR × 100) and postoperative CKD development were investigated. The eGFR decreased significantly at 1 month and remained stable in the PA group. However, there were no significant changes in eGFR in the non-PA group over the 6-month period. In the PA group, a high preoperative eGFR and high aldosterone to renin ratio (ARR) were independently associated with eGFR% decline at 1 month. In patients with PA but without preoperative CKD (n = 68), a low preoperative eGFR and high ARR were independent risk factors for developing postoperative CKD. The best preoperative cut-off values of eGFR and ARR for predicting the development of postoperative CKD were ≤ 102 ml/min/1.73 m2 and ≥ 448 ng/dl:ng/ml/h, respectively. Renal function deteriorated significantly after unilateral adrenalectomy in patients with PA. Clinicians must pay attention to postoperative renal function in PA patients at elevated risk of developing decreased kidney function.
