Coaching adults with stage 3 chronic kidney disease (CKD) to increase water intake did not significantly slow decline in kidney function, results of a randomized clinical trial show.
Compared with coaching to maintain water intake, coaching to increase water intake did in fact increase water intake but did not prevent a decrease in estimated glomerular filtration rate (eGFR) over 1 year, according to findings of the study, which was published in JAMA..
However, the study may have been underpowered to detect a clinically important difference in this primary endpoint, and certain secondary endpoints did suggest a favorable effect of the intervention, according to William F. Clark, MD, of the London (Ontario) Health Sciences Centre and his coauthors.
“The increased water intake achieved in this trial was sufficient to lower vasopressin secretion, as assessed by plasma copeptin concentrations,” Dr. Clark and his colleagues said in their report
An increasing number of studies suggest that drinking water may benefit the kidneys. In some human studies, water intake was associated with reduced risk of kidney stones and better kidney function.
However, it remains unknown whether increasing water intake would benefit patients with CKD. To evaluate this question, Dr. Clark and colleagues initiated CKD WIT (Chronic Kidney Disease Water Intake Trial), a randomized clinical trial conducted in 9 centers in Ontario.
The study included 631 patients with stage 3 CKD and a 24-hour urine volume below 3 L. Patients randomized to the hydration group were coached to increase water intake gradually to 1-1.5 L/day for 1 year, while those randomized to the control group were coached to maintain their usual water intake.