This is a prospective 5-year study to compare the change in total kidney volume (TKV) before and after tolvaptan therapy, as the primary endpoint, in patients with ADPKD.

Tolvaptan was approved in Japan for the treatment of autosomal dominant polycystic kidney disease (ADPKD) in March 2014. This is a prospective 5-year study to compare the change in total kidney volume (TKV) before and after tolvaptan therapy, as the primary endpoint, in patients with ADPKD. Study results will be summarized, analyzed, and compiled into a research paper at 3 years (data cut-off, March 31, 2018) and at 5 years (data cut-off, March 31, 2020)

Inclusion Criteria:

• The patients with ADPKD
• The patients who consent to the study protocol
• Estimated glomerular filtration rate (eGFR) or Creatinine Clearance greater than 50ml/min/1.73m2

Exclusion Criteria:

• Patients who might be danger to drink large amount of water such as having heart failure or past history of cerebrovascular or cardiovascular disorders.
• The patients who take habitual medication which affects the AVP action such as selective serotonin reuptake inhibitors (SSRI ), tricyclic antidepressants or diuretics.
• The patients who is considered inappropriate by physicians.

The patients who visit Kyorin University Hospital.