Chronic kidney disease score for predicting postoperative masked renal insufficiency in patients with primary aldosteronism.

CONTEXT: Chronic kidney disease (CKD) is sometimes unmasked after unilateral adrenalectomy in patients with primary aldosteronism (PA) without expectation.

OBJECTIVE

Our study aim was to elucidate factors responsible for developing postoperative CKD and to provide a simple scoring system to predict postoperative CKD in PA.

DESIGN AND PATIENTS: Forty-five patients with PA treated with unilateral adrenalectomy and followed for at least 1 month postsurgery were studied. Thirty-one patients with non-PA adrenal disease who underwent unilateral adrenalectomy were also studied as control. Patients with pre-operative estimated glomerular filtration rate (eGFR) < 60 ml/min/1·73 m(2) were excluded from both groups.

RESULTS

A statistically significant (P < 0·001) decrease in eGFR was observed in PA group within 1 month of surgery, then stabilized. Of the 45 patients with PA, 17 (37·8%) developed CKD after surgery. None of the non-PA group developed CKD after surgery. Of the pre-operative variables, logistic regression analysis showed that lower eGFR and higher aldosterone-to-renin ratios (ARR) were the independent predictors for postoperative CKD in PA. Optimal cut-off values of the two variables analysed with ROC curves were as follows: eGFR ≤ 76·9 ml/min/1·73 m(2) and ARR ≥ 305. Using these data, we created a CKD score as a tool for predicting postoperative CKD, with an AUC for the score of 0·8866.

CONCLUSION

The pre-operative eGFR and ARR were the significant contributing factors for postoperative CKD in PA. By combining these independent factors, we created a CKD score which provides useful information before surgery about the risk for development of postoperative CKD.