Water intake and progression of chronic kidney disease: the CKD-REIN cohort study

Abstract

Background Optimal daily water intake to prevent chronic kidney disease (CKD) progression is unknown. Taking kidney urine-concentrating ability into account, we studied the relation of kidney outcomes in patients with CKD to total and plain water intake and urine volume. Methods Including 1265 CKD patients (median age, 69 years; mean estimated glomerular filtration rate [eGFR], 32 ml/min per 1.73 m2) from the CKD-REIN cohort (2013-2019), we assessed fluid intake at baseline interviews, collected 24-h urine volumes, and estimated urine osmolarity (eUosm). Using Cox and then linear mixed models, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for kidney failure and eGFR decline associated with hydration markers, adjusting for CKD progression risk factors and eUosm. Results Patients' median daily intake was 2.0 (interquartile range: 1.6-2.6) L total water and 1.5 (1-1.7) L plain water; median urine volume was 1.9 (1.6-2.4) L/24 h, and mean eUosm, 374 ± 104 mosm/L. Neither total water intake nor urine volume was associated with either kidney outcome. Kidney failure risk increased significantly with decreasing eUosm below 292 mosm/L. Adjusted HRs for kidney failure associated with plain water intake were 1.88 (95%CI 1.02; 3.47), 1.59 (1.06; 2.38), 1.76 (0.95; 3.24), and 1.55 (1.03; 2.32) in patients drinking <0.5, 0.6-1.0, 1.6-2.0, and >2.0 L/day, compared with those drinking 1.0-1.5 L/day. High plain water intake was also significantly associated with faster eGFR decline. Conclusion In patients with CKD, the relation between plain water intake and progression to kidney failure appears to be U-shaped. Both low and high intake may not be beneficial in CKD.

Prevalence of chronic kidney diseases and its determinants among Iranian adults: results of the first phase of Shahedieh cohort study

“…In a study in 2021, Wagner et al showed that the relation between plain water intake and progression to kidney failure might be U-shaped. Low and high intake may not have merits for CKD [61]. Clark et al in a pilot randomized controlled trial reported that there were no significant changes in urine, serum osmolality or electrolyte concentrations, or eGFR between two groups of receiving adjusted water intake and control groups [62].…”

Clinical characteristics and outcomes of hyponatraemia associated with oral water intake in adults: a systematic review

“…18 22 23 Interestingly, a recent observational cohort study suggested that water intake may have a U-shaped relationship in the prevention of kidney disease progression. 24 Hence, clinical trials are in progress to prospectively evaluate the efficacy and safety of prescribed water intake for the secondary prevention of chronic diseases. [25][26][27] Whether recommending water intake in healthcare 27 or prescribing water intake in a clinical research trial it is important to understand the circumstances that could result in water intoxication.…”

The impact of diabetes on heart failure development: The cardio-renal-metabolic connection

“…It is presently unknown whether CKD patients (as well as subjects from the general population) should increase or reduce or have the same daily water intake to prevent further renal dysfunction and/or HF risk. In a recent study, a U-shape relationship was observed between daily water intake and degradation of renal function in 1,245 CKD patients (eGFR 15-60 ml/min/1.73m²) from the CKD-REIN cohort study [140]. Nevertheless, some trials are ongoing to assess if supplemental water can slow the loss of kidney function in CKD patients [141].…”