Effect of coaching to increasewater intake on kidney function decline in adults with chronic kidney disease the CKD WIT randomized clinical trial

Abstract

IMPORTANCE In observational studies, increased water intake is associated with better kidney function. OBJECTIVE To determine the effect of coaching to increase water intake on kidney function in adults with chronic kidney disease. DESIGN, SETTING, AND PARTICIPANTS The CKD WIT (Chronic Kidney DiseaseWater Intake Trial) randomized clinical trial was conducted in 9 centers in Ontario, Canada, from 2013 until 2017 (last day of follow-up,May 25, 2017). Patients had stage 3 chronic kidney disease (estimated glomerular filtration rate [EGFR] 30-60 mL/min/1.73m2 and microalbuminuria or macroalbuminuria) and a 24-hour urine volume of less than 3.0 L. INTERVENTIONS Patients in the hydration group (n = 316) were coached to drink more water, and those in the control group (n = 315) were coached to maintain usual intake. MAIN OUTCOMES AND MEASURES The primary outcomewas change in kidney function (EGFR from baseline to 12 months). Secondary outcomes included 1-year change in plasma copeptin concentration, creatinine clearance, 24-hour urine albumin, and patient-reported overall quality of health (0 [worst possible] to 10 [best possible]). RESULTS Of 631 randomized patients (mean age, 65.0 years; men, 63.4%; mean EGFR, 43 mL/min/1.73m2; median urine albumin, 123mg/d), 12 died (hydration group [n = 5]; control group [n = 7]). Among 590 survivors with 1-year follow-up measurements (95%of 619), the mean change in 24-hour urine volume was 0.6 L per day higher in the hydration group (95%CI, 0.5 to 0.7; P