Hypokalaemia and peritoneal dialysis-related peritonitis: Association, risk factors and outcomes

BackgroundPeritonitis is a serious complication associated with risks of death and transfer to haemodialysis for patients receiving peritoneal dialysis (PD). To mitigate such risks, it is important to identify potentially reversible risk factors, such as hypokalaemia.MethodPatients who started PD at the Princess Alexandra Hospital, Australia from 1^st January 2013 to 31^st December 2022 were included. Hypokalaemia, defined as serum potassium <3.5 mmol/L, was assessed at the time of PD initiation and evaluated as categories (<3.5 mmol/L, 3.5-4.5 mmol/L and >4.5 mmol/L) based on 6-month average after PD commencement. Time to first peritonitis was examined using multi-variable Cox survival analyses censored for transplantation, recovery of kidney function or loss to follow up. Competing risk regression was conducted as sensitivity analysis. Peritonitis rates were compared using Poisson regression analysis.ResultsIn total, 486 patients were included. 6-Month average serum potassium level was <3.5 mmol/L in 30 patients (6.2%), 3.5-4.5 mmol/L in 301 patients (62%) and >4.5 mmol/L in 155 patients (32%). During the study period, 192 patients experienced peritonitis with comparable proportions across all three groups (35%, 40% and 40%, respectively). Using multi-variable regression modelling, we found that time to first peritonitis was not significantly associated with hypokalaemia based on 6-month average (hazard ratio 1.14, 95% confidence interval [CI] 0.67-1.95) or baseline hypokalaemia (hazard ratio 0.73, 95% CI 0.34-1.54). Using the categories based on 6-month average serum potassium level, mean peritonitis rate was higher among patients in the <3.5 mmol/L group (0.79 episodes/patient-year) compared to those in the 3.5-4.5 mmol/L (0.61 episodes/patient-year) and >4.5 mmol/L (0.47 episodes/patient-year), whilst the difference was not significant (<i>p</i> = 0.14).ConclusionIn this study, no significant association was identified between hypokalaemia and risk of peritonitis, although estimates were imprecise.