Prescribed Water Intake in Autosomal Dominant Polycystic Kidney Disease

Area of Science:

• Nephrology
• Genetics
• Clinical Trials

Background:

• Arginine vasopressin contributes to kidney cyst progression in autosomal dominant polycystic kidney disease (ADPKD).
• Increased water intake may mitigate ADPKD progression by reducing vasopressin levels and urine osmolality.

Purpose of the Study:

• To investigate the efficacy of prescribed high water intake in slowing kidney cyst growth in ADPKD patients.
• To compare the effects of prescribed versus ad libitum water intake on total kidney volume and urine osmolality.

Main Methods:

• A 3-year randomized controlled trial involving 184 adults with ADPKD (Mayo imaging subclass 1B-1E, eGFR ≥30 ml/min/1.73 m²).
• Participants were assigned to either prescribed water intake to achieve urine osmolality ≤270 mOsmol/kg or ad libitum water intake.
• Primary endpoint: annualized rate of change in height-corrected total kidney volume.

Main Results:

• No significant difference in the annualized growth rate of total kidney volume between the prescribed (6.8%/year) and ad libitum (7.8%/year) water intake groups.
• Prescribed water intake achieved target urine osmolality in 52.3% of patients but did not reduce serum copeptin levels.
• Adverse event frequencies were similar between the two groups over the 3-year study period.

Conclusions:

• Prescribed high water intake in ADPKD patients did not significantly slow total kidney volume growth compared to ad libitum intake over 3 years.
• While achieving target urine osmolality in half of the participants, the intervention did not reduce serum copeptin.
• The strategy of prescribed water intake is safe but not effective in altering ADPKD progression as measured by total kidney volume growth.