Tolvaptan and the role of kidney aquaporin-2 abundance in managing volume overload in patients with CKD

Abstract

ABSTRACT Objective This retrospective study evaluated tolvaptan's efficacy, safety, and predictive indicators in managing volume overload in chronic kidney disease (CKD) patients. Methods CKD patients with volume overload, treated with loop diuretics alone or with tolvaptan at Zhongda Hospital, Southeast University, from 1 March 2022 to 31 December 2023, were included. Patients were divided into loop diuretic (Group C) and loop diuretic combined with tolvaptan (Group T) cohorts. Primary outcomes included volume control, changes in weight, urine output, and laboratory parameters within 1 week post-medication. Adverse events such as hypernatremia and hyperkalemia, etc., were recorded. We further conducted immunohistochemical staining of renal biopsy tissues to investigate the roles of aquaporin-2 (AQP2) in the collecting duct and plasma albumin in predicting the efficacy of tolvaptan. Results Of 174 CKD patients with volume overload, 108 (67.07%) were male. Group C and Group T each comprised 87 patients. At baseline, no significant differences in urine output and weight were noted. By day 3, Group T exhibited a greater increase in urine output (P < .001) and weight reduction (P < .001). At day 7, Group T maintained more significant diuretic effects (P < .001). More Group C patients required ultrafiltration therapy (P = .040). Adverse event rates did not significantly differ. Notably, AQP2 expression in the collecting duct may predict tolvaptan responsiveness, while plasma albumin did not affect efficacy. Conclusion Tolvaptan showed efficacy and safety in managing volume overload in CKD patients. The expression of AQP2 in the collecting duct could predict tolvaptan's efficacy. This study protocol was approved by the Ethics Committee of Zhongda Hospital Affiliated to Southeast University (Approval No. 2023ZDSYLL180-P01, Clinical Trial Registration No. ChiCTR2300075274, Trial Registration Link: https://www.chictr.org.cn/guide.html).