Abstract: FR-PO1068

Effect of Drinking More Water on Kidney Function Decline in Adults with CKD: A Randomized Clinical Trial

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 305 CKD: Clinical Trials and Tubulointerstitial Disorders

Author

  • Clark, William F., London Health Sciences Center, London, Ontario, Canada

Group or Team Name

  • Water Intake Trial (WIT) Investigators
Background

Drinking more water is associated with a slower rate of kidney function decline in animal experiments and human observational studies. We conducted a clinical trial to determine whether drinking more water slows the decline in estimated glomerular filtration rate (eGFR) over one year in patients with chronic kidney disease (CKD).

Methods

Design: Randomized controlled trial.
Setting: Nine centers in Ontario, Canada (2013–17).
Participants: Adults with stage 3 CKD and microalbuminuria.
Intervention: The hydration group was coached to drink more water above their usual fluid intake and the control group to maintain usual fluid intake.
Analysis: The primary outcome was the one-year change in eGFR. Secondary outcomes included the one-year change in plasma copeptin, 24-hr urine albumin, 24-hr creatinine clearance, and health-related quality of life. In the primary analysis patients were analyzed according to random assignment (intention to treat), and in additional analyses by protocol adherence, defined using 24-hr urine volume (per-protocol).

Results

Of 631 randomized patients (mean age 65, men [63%], diabetes [48%], mean eGFR 43 mL/min/1.73m2) 2% died within one year and 95% of survivors provided one-year follow-up measurements. At 12 months, the 24-hr urine volume was 0.6 L/day higher in the hydration group than the control group (95% CI, 0.5 to 0.7; p<0.001). The average one-year decline in eGFR was 2.2 mL/min/1.73m2 in the hydration group and 1.9 mL/min/1.73m2 in the control group, and the adjusted between-group difference in change was -0.3 mL/min/1.73m2 (95% CI, -1.7 to 1.2; p=0.74). Results were similar in the per-protocol analysis. No significant between-group difference in one-year change was seen for 24-hour urine albumin or health-related quality of life. However, at one year, plasma copeptin concentrations were lower in the hydration group than the control group (the between-group difference in one-year change was -2.3 pmol/L [95% CI, -3.9 to -0.6; p=0.009]), while 24-hr creatinine clearance was higher in the hydration group compared to the control group (the between-group difference in one-year change was 3.6 mL/min/1.73m2 [95% CI, 0.8 to 6.5; p=0.012]).

Conclusion

Among patients with stage 3 CKD, the average one-year change in eGFR did not differ in patients who drank more water compared with those who continued their usual fluid intake.

Funding

  • Commercial Support