Does Drinking More Water Preserve Kidney Function? Interview with:
“Glass of Water” by Greg Riegler is licensed under CC BY 2.0Dr. William Clark
Lawson Health Research Institute What is the background for this study? What are the main findings?

Response:  This study is about the use of increased water intake in people with chronic kidney disease (CKD).

Although there are a large number of benefits claimed most are not substantiated by evidence. However there is a growing body of evidence (animal and human observational studies) that increased hydration with the suppression of antidiuretic hormone preserves kidney function in CKD. This led to our current randomised clinical trial of 631 patients with stage 3 CKD and proteinuria to determine if drinking an extra 4-6 glasses of water per day for 1 year would slow their progressive loss of kidney  function as measured by eGFR.

The main findings were that those coached to increase their water intake versus those coached to sustain their normal fluid intake suffered no ill effects from the intervention and on average were able to sustain an average increase of approximately 3 glasses of water per day. At the end of 1 year the increased hydration group had suppressed their antidiuretic hormone levels (copeptin) significantly but did not demonstrate a greater preservation in their eGFR. What should clinicians and patients take away from your report?

Response: At present coaching to increase hydration does not show preservation in kidney function in patients with stage 3 CKD and proteinuria. What recommendations do you have for future research as a result of this study?

Response: We have completed phase 1 of the hydration study and will be completing a further year in June to see if the effect is time dependent. We encourage a focus on low water drinkers to see if this subgroup will show the increased hydration benefit noted by prior observational studies (study just initiated  by Dr Olle Melander in Sweden). This is the first step in defining the potential therapeutic role of increased hydration in slowing kidney decline  in CKD. Thank you for your contribution to the community.


Clark WF, Sontrop JM, Huang S, et al. Effect of Coaching to Increase Water Intake on Kidney Function Decline in Adults With Chronic Kidney DiseaseThe CKD WIT Randomized Clinical TrialJAMA.2018;319(18):1870–1879. doi:10.1001/jama.2018.4930

Note: Content is Not intended as medical advice. Please consult your health care provider regarding your specific medical condition and questions. 

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Last Updated on May 11, 2018 by Marie Benz MD FAAD