Water Vs Tolvaptan in Reducing ADPKD Progression

WATSAPP trial is a three arm, double blinded,randomized, multi centre 2 year trial to answer the question whether increased water intake is effective in reducing ADPKD cyst size and progression. 1500 patients of ADPKD with estimated creatinine clearance greater than 60 ml per min and baseline kidney volume of 750 ml or more will be randomized to receive:

1. Placebo
2. Tolvaptan twice daily (30-90 mg as tolerated)
3. Water intake alone (3L-4L per day) (justification for water intake volume here)

Outcome measures:

1. Change in kidney volume
2. Change in creatinine clearance
3. Worsening Hypertension (need for stepping up to 1 or more anti hypertensive than required at baseline)