Changes in kidney function after adrenalectomy in patients with primary aldosteronism.

Objectives: A decrease in the estimated glomerular filtration rate (eGFR) is occasionally observed in patients with primary aldosteronism (PA) after adrenalectomy. Patients may misunderstand that the surgical stress of adrenalectomy can result in kidney dysfunction. However, this finding is considered due to postoperative manifestations of kidney dysfunction that are masked preoperatively by excess aldosterone. To evaluate kidney dysfunction unmasked by adrenalectomy, we investigated changes in the eGFR after adrenalectomy according to the clinically assessable indication of "a certain drop in eGFR" as defined by the 2012 Kidney Disease Improving Global Outcomes clinical practice guideline.

Methods: This study included 54 patients with PA who underwent unilateral adrenalectomy between 2005 and 2022 at our institution. We classified patients by GFR categories defined by the guideline according to their pre- and postoperative eGFR. We analyzed the predictors associated with a certain drop in eGFR (i.e., a decrease in GFR category accompanied by a ≥25% decrease in the eGFR from baseline).

Results: A certain drop in eGFR was present in 35.2% of patients after adrenalectomy. Multivariate regression analysis showed that a longer duration of hypertension, lower preoperative serum potassium concentrations, and lower serum potassium concentrations before potassium supplementation were significant independent predictors (p<0.05). The cut-off value of the preoperative serum potassium concentrations was 3.7 mmol/L according to receiver operating characteristic curve analysis.

Conclusions: Our findings will be useful for surgeons in informing patients with PA regarding the possibility of downgrading GFR categories after adrenalectomy.