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Kidney Week

Abstract: TH-PO839

Differential Effects of Tolvaptan on Total Kidney Volume in Autosomal Dominant Polycystic Kidney Disease Patients with PKD1 and PKD2 Mutations

Session Information

Category: Genetic Diseases of the Kidneys

  • 1001 Genetic Diseases of the Kidneys: Cystic

Authors

  • Moriyama, Tomofumi, Kurume University School of Medicine, Kurume, Japan
  • Nakayama, Yosuke, Kurume University School of Medicine, Kurume, Japan
  • Kaida, Yusuke, Kurume University School of Medicine, Kurume, Japan
  • Ito, Sakuya, Kurume University School of Medicine, Kurume, Japan
  • Kodama, Goh, Kurume University School of Medicine, Kurume, Japan
  • Kurokawa, Yuka, Kurume University School of Medicine, Kurume, Japan
  • Fukami, Kei, Kurume University School of Medicine, Kurume, Japan
Background

Autosomal dominant polycystic kidney disease (ADPKD) is the most common renal disease with a genetic origin. The renal prognosis of patients with polycystin 1 (PKD1) mutations was reported to be worse than those with PKD2 mutations. At our hospital, 17 patients with ADPKD with known gene mutation profiles have been treated with the vasopressin antagonist tolvaptan since 2015. However, the relationship between specific gene mutations and the protective effect of tolvaptan on kidney volume and renal function remains unclear. Therefore, we assessed outcomes of patients with different gene mutations after one-year tolvaptan treatment.

Methods

All patients provided consent for genetic analyses. Genetic analysis by Sanger sequencing with a 3730 DNA analyzer was performed in 17 ADPKD patients, including 8 males and 9 females (mean age; 51 ± 11 years), who were treated with tolvaptan for one year. Total kidney volume (TKV) was evaluated with computer tomography using Ziostation 2, an auto-analysis system for TKV measurement.

Results

Mean values for TKV, eGFR, Δ%TKV/year, and ΔeGFR were 1569 ± 575 ml, 56.0 ± 22.5 ml/min/1.73 m2, 14.1 ± 6.1%, and −5.9 ± 7.5 ml/min/1.73 m2, respectively. PKD1 and PKD2 mutations were found in 4 and 3 patients, respectively, whereas no mutations in either gene were found in the remaining ten patients. The baseline total TKV, renal function, and changes in TKV did not differ among the patients with PKD1 and PKD2 mutations and those with unknown status (TKV, 1199 ± 212, 1449 ± 277, and 1770 ± 667 ml; eGFR, 58.6 ± 22.7, 60.7 ± 11.7, and 53.6 ± 24.4 ml/min/1.73 m2; Δ%TKV/year, 10.8 ± 2.7%, 12.3 ± 4.3%, and 15.9 ± 6.7%, respectively). Tolvaptan treatment significantly improved the Δ%TKV/year in patients with PKD1 mutations (−8.3 ± 10.2%, p = 0.03) and those with unknown status (−6.8 ± 8.6%, p < 0.001), but not in those with PKD2 mutations (−1.7 ± 8.8%, p = 0.20). ΔeGFR did not change in any of the groups studied.

Conclusion

One-year tolvaptan treatment reduced Δ%TKV/year in patients with ADPKD with PKD1 mutations and those with unknown mutation status but not in those with PKD2 mutations.

Funding

  • Private Foundation Support