Serum Sodium Levels and Patient Outcomes in an Ambulatory Clinic-Based Chronic Kidney Disease Cohort

Abstract

Background: Chronic kidney disease (CKD) patients are prone to both hypo- and hypernatremia. Little has been published on the epidemiology of hypo- and hypernatremia in ambulatory patients with non-dialysis CKD. Methods: Data collected in two contemporaneous CKD cohort studies, the Renal Research Institute (RRI)-CKD study (n = 834) and the Study of Treatment of Renal Insufficiency: Data and Evaluation (STRIDE) (n = 1,348) were combined and analyzed to study the association between serum sodium (Na⁺) and clinical outcomes. Results: Baseline estimated glomerular filtration rate (eGFR) and Na⁺ were 26 ± 11 ml/min/1.73 m² and 140.2 ± 3.4 mEq/l, respectively. The prevalence of Na⁺ ≤135 mEq/l and ≥144 mEq/l was 6 and 16%, respectively. Higher baseline Na⁺ was significantly associated with male sex, older age, systolic blood pressure, BMI, serum albumin, presence of heart failure, and lower eGFR. The risk of end-stage renal disease (ESRD) was marginally significantly higher among patients with Na⁺ ≤135 mEq/l, compared with 140< Na⁺ <144 mEq/l (referent), in time-dependent models (adjusted hazard ratio, HR = 1.52, p = 0.06). Mortality risk was significantly greater at 135< Na⁺ ≤140 mEq/l (adjusted HR = 1.68, p = 0.02) and Na⁺ ≥144 mEq/l (adjusted HR = 2.01, p = 0.01). Conclusion: CKD patients with Na⁺ ≤135 mEq/l were at a higher risk for progression to ESRD, whereas both lower and higher Na⁺ levels were associated with a higher risk of mortality. While caring for CKD patients, greater attention to serum sodium levels by clinicians is warranted and could potentially help improve patient outcomes.

Outcomes in medical admissions with hyponatraemia in Ghana – a single-centre study

“…CKD is another cause of hypervolaemic hyponatraemia, with a prevalence of 6% in non-dialysis CKD patients [25]. CKD accounted for 6% of our cases.…”

Association of serum sodium and risk of all-cause mortality in patients with chronic kidney disease: A meta-analysis and sysematic review

“…1 ). Thus, seven studies 9 – 14 , 19 that comprised of 742,979 CKD patients were included in the meta-analysis. Table 1 presents the baseline characteristics of the included studies.…”

“…Table 1 presents the baseline characteristics of the included studies. Among the seven articles, four studies 9 , 11 , 14 , 19 were limited to non-dialysis CKD patients, two studies 10 , 12 enrolled hemodialysis patients, and one study 13 included peritoneal dialysis patients. Furthermore, five studies 9 , 10 , 12 – 14 were conducted in the United States, Korea 19 and the United Kingdom 11 , in which each country contributed one study.…”

“…Hyponatremia and hypernatremia are relatively frequent electrolyte abnormalities in patients with advancing stages of CKD, who are undergoing dialysis 8 . Several 9 – 17 but not all 18 , 19 epidemiologic studies reported that hyponatremia is associated with increased all-cause mortality in no-dialysis CKD and maintenance dialysis patients. Similarly, the association of hypernatremia with all-cause mortality risk has also yielded inconsistent results 9 , 11 – 14 , 19 .…”

Possible association between dysnatremias and mortality during hospitalization in patients undergoing acute hemodialysis: analysis from a Peruvian retrospective cohort

“…These include changes of urine dilution and concentration in response to antidiuretic hormone, and alteration of water and Na and CI reabsorption and excretion 13,14 . Previous studies have reported that dysnatremias and hypochloremia are associated factors for mortality in patients with chronic kidney disease (CKD), with or without dialysis [15][16][17][18][19][20][21][22] . Thus, dyschloremias and dysnatremias have been proposed as potential useful factors for mortality prediction in this population [15][16][17][18][19][20][21][22] .…”