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Hyponatremia, defined as a serum sodium concentration less than 136 mmol/L, is one of the most common electrolyte disorders between inpatient and outpatient care. Kidneys are the mainstay of hydroelectrolytic balance (including sodium). Several studies have shown that hyponatremia has direct association with increased risk factors for falling, fractures, prolonged hospital stay and general mortality rate. Following kidney transplantation, various deleterious factors, including delayed graft function, transplant rejection episodes, diuretics, and immunosuppressant drugs, exert a prolonged influence on sodium homeostasis.
Data from Hospital Regional Valentin Gomez Farias during February 2023 to November 2023 were collected. Inclusion criteria involved patients with kidney transplant and at least two measurements of serum sodium less than 136 mEq/dL on the first week post-transplantation. Serum sodium levels were determined daily during their first 7 days and every week during one-month follow-up. Clinical and biochemical parameters were categorized to identify factors related to hyponatremia presentation and outcomes like delayed graft function, transplant rejection episodes, or mortality.
During the time of observation 12 out of 15 patients showed at least one episode of hyponatremia during the time of follow up. Those 12 patients were enrolled in this study. We calculated an 80% incidence of hyponatremia among these patients. Pre-transplant sodium levels were 136.7 ± 3.40 mmol/L. The mean sodium after transplantation were 131.84 ± 4.88 mmol/L. After one month of follow up we found an improvement on sodium levels of 137.25 ± 2.87 mmol/L. In regard of glomerular filtration rate, we made an estimation at discharge of 69.66 ± 27.99 ml/min/m² and at one-month follow-up we calculated a glomerular filtration rate of 77.63 ± 20.21 ml/min/m². In terms of hospitalization days, patients with hyponatremia had prolonged length of stay of 10.58 ± 4.64 days compared with non-hyponatremic patients (5 days).
We concluded patients with hyponatremia did not exhibit a lower glomerular filtration rate but did had longer hospital stay. During one-month follow-up, none of those kidney recipients had delayed graft function, transplant rejection episodes nor mortality. The incidence of post-transplant hyponatremia in our population was higher than previously reported evidence.