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Hypokalemia (defined as serum potassium <3,5 mEq/l) is a common electrolyte imbalance, however, it is often not treated in patients on dialysis despite being associated with an increased risk of morbidity and mortality. Hypokalemia occurs when there is an imbalance between intake, elimination and transcellular movement of potassium. The severity of clinical manifestations depends on the potassium concentration, intracellular/extracellular potassium ratio, and speed of establishment. In the present study, the main objective is to evaluate the association between hypokalemia and the probability of developing peritonitis in PD. There is one hypothesis that associate hypokalemia with an increase in the incidence of peritonitis in PD due to paralyticus ileus, which is a risk factor for bacterial overgrowth and bacterial translocation in the peritoneal fluid. Other hypothesis described is that hypokalemia may also serve as a marker of malnutrition and immune system impairment with a reduction of the defense mechanisms of the peritoneal membrane against infectious agents.
We conducted an analytical, observational retrospective study of prevalent patients undergoing PD at the Durand Hospital from February 1998 to October 2023 and serum potassium 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. 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 potassium in the group that developed peritonitis was 4.48 mEq/l (SD 0.89), and 4.58 mEq/l (SD 0.67) in those who did not develop peritonitis (p=0,41). The presence of hypokalemia was observed in 9,7% of the population, meanwhile, on those who developed peritonitis the presence of hypokalemia was observed in 11% of the patients. After analyzing the data, it was evident that time on PD was not associated with the development of hypokalemia (p=0.58). When the mean potassium 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 hypokalemia (14 patients), it is observed that 50% develop peritonitis. When potassium is evaluated in those who present more than 1 episode compared to just one, no statistically significant difference is observed (p=0.61).
Hypokalemia is an entity that causes increased morbidity and mortality and is frequently observed in PD patients, with a prevalence of 9.7% in this studied population sample. In various studies, hypokalemia has been correlated with an increase in the incidence of peritonitis, but in our study this correlation was not evident. However, due to the complications of suffering from this entity, it is recommended to treat all patients, including PD patients, even if they are mild or asymptomatic and regardless of the risk or not, of suffering more incidence of peritonitis.