Long-Term Effects of Tolvaptan Therapy on Total Kidney Volume and Renal Function in Patients with Autosomal Dominant Polycystic Kidney Disease: A Single-Center Experience

Background: Tolvaptan, a vasopressin V2 receptor antagonist, is the only approved disease-modifying therapy for Autosomal Dominant Polycystic Kidney Disease (ADPKD), yet real-world data on its long-term effectiveness remain limited. Methods: In this single-center retrospective study, we evaluated 30 patients with ADPKD who received tolvaptan therapy for at least three years between 2019 and 2024. All patients met standard inclusion criteria and underwent serial magnetic resonance imaging to assess total kidney volume (TKV), along with longitudinal monitoring of renal function using estimated glomerular filtration rate (eGFR). Results: At the end of follow-up, the median annual TKV growth rate was 4.27% (IQR: 1.39–7.98), which did not differ significantly from the predicted without treatment growth rate of 5.3% (95% CI: −2.75 to 0.69, p = 0.194). Although the impact on TKV was limited, tolvaptan notably slowed the decline in kidney function, with a median eGFR of 65 mL/min/1.73 m2 at follow-up, compared to a predicted value of 60.8 mL/min/1.73 m2 (95% CI: −14.60 to −6.18, p < 0.001), reflecting a 33.9% relative benefit. In 80% of patients, renal function after three years was better than predicted. Conclusions: These findings suggest that tolvaptan provides significant functional benefit in ADPKD patients in routine clinical practice, even in the absence of marked suppression in TKV growth and support its continued use in carefully selected individuals.