Randomised controlled trialindependent cross-checkabstract checked I-GUT-117 in-depth review

More water did not slow kidney disease

Effect of Coaching to Increase Water Intake on Kidney Function Decline in Adults With Chronic Kidney Disease: The CKD WIT Randomized Clinical Trial.

Overview

Clark WF et al.. JAMA 2018 · PMID 29801012 · DOI 10.1001/jama.2018.4930

Coaching people with kidney disease to drink about 0.6 L more per day did not change kidney function over a year.

Does the study support the specific claim? Partly · Methodological quality: high

Study explained simply

What did the researchers want to find out?: Test extra water in CKD.
How was the study done?: RCT, 12 months.
How many people, animals or samples were studied?: 631 adults.
What was actually found?: No difference in eGFR decline.
How large was the observed effect?: -0.3 mL/min (-1.8 to 1.2).
What do the results mean in everyday life?: Extra water is not a treatment for everyone, but it was not harmful here.
What are the study's limitations?: Short; no liver outcomes.
What does it say about Elawady's specific claim?: Partly supports not over-drinking; does not support liver harm.
Do the results apply to Germany and Europe?: Applicable.
What can explicitly not be concluded from this study?: Cannot show liver effects.

Does coaching to increase water intake slow kidney function decline in stage 3 CKD?

Study design: Randomised controlled trial – Multicentre randomised controlled trial, 12 months
Population: Adults with stage 3 CKD and albuminuria, urine volume <3 L/day
Country: Canada
Period: 2013-2017
Sample size: 631 randomised
Inclusion and exclusion criteria: eGFR 30-60 with micro/macroalbuminuria

Exposure / intervention: Coaching to drink more water
Comparator: Coaching to maintain intake
Endpoints: Change in eGFR; copeptin, creatinine clearance, albuminuria, quality of health
Statistical methods: Adjusted between-group differences

Results: Urine volume +0.6 L/day (0.5-0.7). eGFR change -2.2 vs -1.9; difference -0.3 (-1.8 to 1.2; P=.74). Copeptin -2.2 pmol/L (P=.01). Deaths 5 vs 7.
Absolute risks: Not applicable
Authors' conclusion: Increasing water intake did not significantly slow kidney decline over 1 year; may be underpowered.

Null primary result with CI excluding large benefit or harm to eGFR.

Partly supports the idea that 'flooding' with extra water brings no automatic benefit; also shows extra water did not harm kidney function.

Kidney stone RCT (I-FAST-09) and cystitis RCT (I-GUT-116) show benefits in specific groups.

Applicable.

Extra water is neither a cure-all nor harmful in this group.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	high
Risk of bias	low
Precision of results	moderate
Directness	indirect
Reproducibility	not replicated
Consistency with the overall evidence	consistent
Regional transferability	high
Adequacy of the interpretation (by the archive)	not applicable

Liver outcomes not studied anywhere.