Association between serum potassium, risk and prognosis of peritonitis in peritoneal dialysis patients - results from the Peritoneal Dialysis Telemedicine-assisted Platform Cohort (PDTAP) Study

Abstract

Background: Hypokalemia has been associated with an increased risk of peritoneal dialysis (PD)-associated peritonitis. However, hypokalemia is commonly associated with malnutrition, inflammation, and severe coexisting comorbidities, which thus are suspected of being potential confounders. This study was aimed at testing whether hypokalemia was independently associated with the occurrence and prognosis of PD-associated peritonitis.

Methods: A national-level dataset from the Peritoneal Dialysis Telemedicine-assisted Platform Cohort (PDTAP) Study was used to explore the independent association of serum potassium with PD-associated peritonitis. Unmatched and propensity score-adjusted multivariate competing risk models, as well as univariate competing risk models following 1:1 propensity score matching, were conducted to balance potential biases between patients with and without hypokalemia. The association between potassium levels prior to peritonitis and treatment failure due to peritonitis was also investigated.

Results: During a median follow-up of 25.7 months in 7220 PD patients, there was a higher incidence of peritonitis in patients with serum potassium below 4.0 mmol/L compared to those with higher serum levels (677 [0.114/patient-year] vs. 914 [0.096/patient-year], P = 0.001). After adjusting for demographics, laboratory tests, residual renal function, and medication use, baseline potassium levels below 4.0 mmol/L were not linked to an increased risk of peritonitis, with a hazard ratio of 0.983 (95% CI 0.855-1.130, P = 0.810). This result remained consistent in both the propensity score adjusted multivariate competing risk regression (HR = 0.974, 95% CI 0.829-1.145, P = 0.750) and the univariate competing risk regression after 1:1 propensity score matching (Fine-Gray test, P = 0.218). The results were similar when analyzing patients with serum potassium level above or below 3.5 mmol/L. Lastly, hypokalemia before the occurrence of peritonitis was not independently associated with treatment failure.

Conclusion: Hypokalemia was not found to be an independent risk factor for PD-associated peritonitis or treatment failure of peritonitis in China.

Keywords: Hypokalemia; PDTAP; Peritoneal dialysis; Peritonitis; Treatment failure.