The chronic kidney disease Water Intake Trial (WIT): results from the pilot randomised controlled trial

Abstract

Background and objectivesIncreased water intake may benefit kidney function. Prior to initiating a larger randomised controlled trial (RCT), we examined the safety and feasibility of asking adults with chronic kidney disease (CKD) to increase their water intake.Design, setting, participants and measurementsBeginning in October 2012, we randomly assigned 29 adults with stage 3 CKD (estimated glomerular filtration rate (eGFR) 30–60 mL/min/1.73 m2 and albuminuria) to one of the two groups of water intake: hydration (n=18) or standard (n=11). We asked the hydration group to increase their water intake by 1.0–1.5 L/day (in addition to usual intake, depending on sex and weight) for 6 weeks, while the control group carried on with their usual intake. Participants collected a 24 h urine sample at baseline and at 2 and 6 weeks after randomisation. Our primary outcome was the between-group difference in change in 24 h urine volume from baseline to 6 weeks.Results(63%)of participants were men, 81% were Caucasians and the average age was 61 years (SD 14 years). The average baseline eGFR was 40 mL/min/1.73 m2 (SD 11 mL/min/1.73 m2); the median albumin to creatinine ratio was 19 mg/mmol (IQR 6–74 mg/mmol). Between baseline and 6-week follow-up, the hydration group's average 24 h urine volume increased by 0.7 L/day (from 2.3 to 3.0 L/day) and the control group's 24 h urine decreased by 0.3 L/day (from 2.0 to 1.7 L/day; between-group difference in change: 0.9 L/day (95% CI 0.4 to 1.5; p=0.002)). We found no significant changes in urine, serum osmolality or electrolyte concentrations, or eGFR. No serious adverse events or changes in quality of life were reported.ConclusionsA pilot RCT indicates adults with stage 3 CKD can successfully and safely increase water intake by up to 0.7 L/day in addition to usual fluid intake.Trial registration Registered with Clinical Trials—government identifierNCT01753466.

Metabolic and Kidney Diseases in the Setting of Climate Change, Water Shortage, and Survival Factors

“…96,97 Currently, there is a randomized trial to determine if supplementation with water to increase urinary output to .3 L/d slows the progression of CKD. 98 Obesity, Metabolic Syndrome, and Hypertension As mentioned, fructose and vasopressin show similar effects to increase fat stores and conserve water (Figure 3). This suggests that transient elevations in serum osmolarity because of either a relative water deficit or a high-sodium diet might be associated with increased risk for obesity and metabolic syndrome.…”

Increasing Water Intake in Chronic Kidney Disease: Why? Safe? Possible?

“…We found no significant change in serum osmolality, sodium concentration, eGFR, or quality of life, and no serious events were reported nor observed. This pilot study demonstrated that patients with chronic kidney disease can successfully and safely increase their water intake by 1 to 1.5 l/day over and above the usual fluid intake with no serious adverse effects [10]. Further, to validate the biologic plausibility of our hypothesis, we examined correlations with copeptin (a surrogate marker of vasopressin): at 6 weeks follow-up, copeptin was inversely correlated with both 24 h urine volume and eGFR [12].…”

“…We wished to address the issue of safety in view of clinician concerns about water intoxication in patients with chronic kidney disease [10]; also, with respect to feasibility, only one study with a pre- and post-study questionnaire showed that 11% of participants were unable to increase hydration, 35% produce daily urine volumes of less than 2 l/day, and 30% reported that they were able to increase their water intake only during non-working hours [11]. For these reasons, as well as concerns about regression to the mean, we needed to test the feasibility of whether subjects coached to increase water intake versus those who were coached to maintain normal fluid intake, would have different urine volumes at the end of the pilot study [10]. Because increased hydration can decrease appetite and increase urination, particularly at night, which could negatively affect sleep patterns, we also compared groups on these measures and on their quality of life.…”

“…These studies offer support for the hypothesis that increased water intake slows progression of chronic kidney disease by lowering vasopressin levels and provide the biologic rationale for conducting a clinical trial. Prior to launching a randomized control trial on the effect of increased water intake on renal decline, we conducted a six-week pilot study to examine the safety and feasibility of asking adults with chronic kidney disease to increase their water intake by 1 to 1.5 l/day [10]. We wished to address the issue of safety in view of clinician concerns about water intoxication in patients with chronic kidney disease [10]; also, with respect to feasibility, only one study with a pre- and post-study questionnaire showed that 11% of participants were unable to increase hydration, 35% produce daily urine volumes of less than 2 l/day, and 30% reported that they were able to increase their water intake only during non-working hours [11].…”

“…Prior to launching a randomized control trial on the effect of increased water intake on renal decline, we conducted a six-week pilot study to examine the safety and feasibility of asking adults with chronic kidney disease to increase their water intake by 1 to 1.5 l/day [10]. We wished to address the issue of safety in view of clinician concerns about water intoxication in patients with chronic kidney disease [10]; also, with respect to feasibility, only one study with a pre- and post-study questionnaire showed that 11% of participants were unable to increase hydration, 35% produce daily urine volumes of less than 2 l/day, and 30% reported that they were able to increase their water intake only during non-working hours [11]. For these reasons, as well as concerns about regression to the mean, we needed to test the feasibility of whether subjects coached to increase water intake versus those who were coached to maintain normal fluid intake, would have different urine volumes at the end of the pilot study [10].…”