Even a year of increased water intake did not change CKD course

 

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.

 

Patients in the hydration group were also given reusable drinking containers and 20 vouchers per month redeemable for 1.5 L of bottled water, investigators reported.

Urine volume did significantly increase in the hydration group versus controls, by 0.6 L per day (P less than .001). However, change in eGFR – the primary outcome – was not significantly different between groups. Mean change in eGFR was –2.2 mL/min per 1.73 m² in patients coached to drink more water and –1.9 mL/min per 1.73 m² in those coached to maintain water intake (P = .74).

Some secondary outcome measures demonstrated significant differences in favor of the hydration group. Plasma copeptin and creatinine clearance both showed significant differences in favor of the hydration group. In contrast, there were no significant differences between intervention arms in urine albumin or quality of health, according to analyses of secondary outcomes described in the study report.

There are several ways to interpret the finding that drinking more water had no effect on eGFR, investigators said. Increasing water intake may simply not be protective against kidney function decline. Perhaps follow-up longer than 1 year would be needed to see an effect, or perhaps there was an effect, but the study was underpowered to detect it.

 

It could also be that a greater volume of water would be needed to demonstrate a protective effect for the kidneys. Despite the coaching efforts of dietitians and research assistants, the mean urine volume increase in the hydration group relative to the control group was just 0.6 liter per day, or 2.4 cups.

“This highlights how difficult it would be to achieve a large sustained increase in water intake in routine practice,” Dr. Clark and colleagues said in their report.

Dr. Clark reported disclosures related to Danone Research. Thermo Fisher Scientific provided instrumentation, assay reagent, and disposables used in the study.

SOURCE: Clark WF et al. JAMA. 2018;319(18):1870-9.

 

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.

 

Patients in the hydration group were also given reusable drinking containers and 20 vouchers per month redeemable for 1.5 L of bottled water, investigators reported.

Urine volume did significantly increase in the hydration group versus controls, by 0.6 L per day (P less than .001). However, change in eGFR – the primary outcome – was not significantly different between groups. Mean change in eGFR was –2.2 mL/min per 1.73 m² in patients coached to drink more water and –1.9 mL/min per 1.73 m² in those coached to maintain water intake (P = .74).

Some secondary outcome measures demonstrated significant differences in favor of the hydration group. Plasma copeptin and creatinine clearance both showed significant differences in favor of the hydration group. In contrast, there were no significant differences between intervention arms in urine albumin or quality of health, according to analyses of secondary outcomes described in the study report.

There are several ways to interpret the finding that drinking more water had no effect on eGFR, investigators said. Increasing water intake may simply not be protective against kidney function decline. Perhaps follow-up longer than 1 year would be needed to see an effect, or perhaps there was an effect, but the study was underpowered to detect it.

 

It could also be that a greater volume of water would be needed to demonstrate a protective effect for the kidneys. Despite the coaching efforts of dietitians and research assistants, the mean urine volume increase in the hydration group relative to the control group was just 0.6 liter per day, or 2.4 cups.

“This highlights how difficult it would be to achieve a large sustained increase in water intake in routine practice,” Dr. Clark and colleagues said in their report.

Dr. Clark reported disclosures related to Danone Research. Thermo Fisher Scientific provided instrumentation, assay reagent, and disposables used in the study.

SOURCE: Clark WF et al. JAMA. 2018;319(18):1870-9.

 

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.

 

Patients in the hydration group were also given reusable drinking containers and 20 vouchers per month redeemable for 1.5 L of bottled water, investigators reported.

Urine volume did significantly increase in the hydration group versus controls, by 0.6 L per day (P less than .001). However, change in eGFR – the primary outcome – was not significantly different between groups. Mean change in eGFR was –2.2 mL/min per 1.73 m² in patients coached to drink more water and –1.9 mL/min per 1.73 m² in those coached to maintain water intake (P = .74).

Some secondary outcome measures demonstrated significant differences in favor of the hydration group. Plasma copeptin and creatinine clearance both showed significant differences in favor of the hydration group. In contrast, there were no significant differences between intervention arms in urine albumin or quality of health, according to analyses of secondary outcomes described in the study report.

There are several ways to interpret the finding that drinking more water had no effect on eGFR, investigators said. Increasing water intake may simply not be protective against kidney function decline. Perhaps follow-up longer than 1 year would be needed to see an effect, or perhaps there was an effect, but the study was underpowered to detect it.

 

It could also be that a greater volume of water would be needed to demonstrate a protective effect for the kidneys. Despite the coaching efforts of dietitians and research assistants, the mean urine volume increase in the hydration group relative to the control group was just 0.6 liter per day, or 2.4 cups.

“This highlights how difficult it would be to achieve a large sustained increase in water intake in routine practice,” Dr. Clark and colleagues said in their report.

Dr. Clark reported disclosures related to Danone Research. Thermo Fisher Scientific provided instrumentation, assay reagent, and disposables used in the study.

SOURCE: Clark WF et al. JAMA. 2018;319(18):1870-9.