Water Intake and eGFR: A Randomized Clinical Trial
Coaching patients with chronic kidney disease (CKD) to drink more water did not significantly affect rates of decline in kidney function, according to the results of a recent study.
While previous research has suggested that water intake is associated with improved kidney function, it is unclear how coaching patients with CKD to increase water intake could affect kidney function.
The researchers conducted their study in 9 centers in Ontario, Canada, from 2013 to 2017. The participants all had stage 3 chronic kidney disease (estimated glomerular filtration rate [eGFR] 30-60 mL/min/1.73 m2 and microalbuminuria or macroalbuminuria) and a 24-hour urine volume of less than 3.0 L.
The participants were randomly divided into 2 groups: the hydration group (n = 316), who were coached to drink more water than they normally would, and the control group (n = 315), who maintained usual water intake.
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The primary outcome was change in kidney function (eGFR), and secondary outcomes included 1-year change in plasma copeptin concentration, creatinine clearance, 25-hour urine albumin, and patient-reported overall quality of health (measured on a 0 to 10 scale).
Overall, 12 patients died during the course of the study. Among the 590 remaining participants with 1-year follow-up measurements, the mean change in 24-hour urine volume was 0.6 L per day higher in the hydration group and the mean change in eGFR was -2.2 mL/min/1.73 m2 in the hydration group and −1.9 mL/min/1.73 m2 in the control group.
The adjusted between-group differences in secondary outcomes were −2.2 pmol/L for plasma copeptin; 3.6 mL/min/1.73 m2 for creatinine clearance; 7 mg per day for urine albumin; and 0.2 points for quality of health.
“Among adults with chronic kidney disease, coaching to increase water intake compared with coaching to maintain the same water intake did not significantly slow the decline in kidney function after 1 year. However, the study may have been underpowered to detect a clinically important difference,” the researchers concluded.
—Michael Potts
Reference:
Clark WF, Sontrop JM, Huang S, et al. Effect of coaching to increase water intake on kidney function decline in adults with chronic kidney disease: The CKD WIT randomized clinical trial. JAMA. 2018;319(18):1870-1879.