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Hyponatremia (defined as serum sodium <135 mEq/l) is a very common electrolyte alteration in patients on peritoneal dialysis (PD) and is a poor prognostic factor and an independent predictive factor of mortality in any pathology. The clinical manifestations produced by hyponatremic encephalopathy are very well known, however, the clinical repercussions of mild or chronic hyponatremia are generally not taken into account. In the present study, the main objective is to evaluate the association between hyponatremia and the probability of developing peritonitis in PD. One of the hypothesis that could associate the relationship between hyponatremia and the development of peritonitis in PD is the volume overload that some of the patients in PD have. This leads to hyponatremia secondary to sodium dilution and intestinal wall edema, which promotes bacterial translocation. Besides, this volume overload causes inflammation and reduces the defense mechanisms of the peritoneal membrane against infectious agents. Another hypothesis proposed is that the presence of hyponatremia may lead to attention deficits, which, probably increases the predisposition to errors in the technique.
We conducted an analytical, observational retrospective study of prevalent patients undergoing PD at the Durand Hospital from February 1998 to October 2023 and serum sodium was evaluated at the time of the peritonitis episode and the month prior to the event. Inclusion criteria were patients who underwent PD in our hospital and who, during the month in which they suffered an episode of peritonitis, had a serum ionogram; or who did not have peritonitis and had a baseline ionogram. A total of 144 patients who met the inclusion criteria were included.
The median follow-up time of the patients was 17.5 months with a interquantile range of 7-35.5 months. Among the 144 patients, 55% of patients did not develop any episode of peritonitis, 20% had one episode, 9% had two peritonitis and 17% had three or more peritonitis episode. The mean serum sodium in the group that developed peritonitis was 137 mEq/l (SD 4.3), and 137 mEq/l (SD 3.6) in those who did not develop peritonitis (p=0,94). The presence of hyponatremia was observed in 26% in those who did not have peritonitis and 26% in those who did. After analyzing the data, it was evident that time on PD was not associated with the development of hyponatremia. When the mean sodium of patients who developed peritonitis is compared with those who did not, no statistically significant difference was found in both groups. Likewise, patients who developed peritonitis did not differ in sodium level. When we evaluate the group that presents hyponatremia (38 patients), it is observed that 44.7% develop peritonitis. Of these 38 patients, 36 developed more than 1 episode of peritonitis. When sodium is evaluated in those who present more than 1 episode compared to just one, no statistically significant difference is observed (p=0.40).
Hyponatremia is an entity that causes increased morbidity and mortality and is frequently observed in patients on PD with a prevalence of 26% in this studied population sample. This study attempted to demonstrate that this entity was associated with a higher incidence of peritonitis, which did not have a statistically significant relationship. However, due to the complications of suffering from these entities, it is recommended to treat them in all patients, including patients on PD even if they are mild or asymptomatic, and regardless of the risk or not of suffering more peritonitis.