Degree and duration of hypokalemia associated with peritonitis in patients undergoing peritoneal dialysis

BACKGROUND Hypokalemia (LK) was associated with peritonitis in peritoneal dialysis (PD) patients, while the role of its degree and duration have not been fully established. Here, we conducted a retrospective cohort study to identify the relationships of LK degree and duration with peritonitis in PD patients. METHODS A total of 602 PD patients in our department from Jan 1st, 2009 to Dec 31st, 2019 entered the last analysis. Data were collected from their medical records. Serum potassium (SK) levels, degree of hypokalemia, and duration of hypokalemia were analysed with peritonitis. The time association of hypokalemia and peritonitis was also analysed. RESULTS There were totally 320 (53.7%) and 123 (20.7%) patients who had ever suffered from LK and serious hypokalemia (SLK) in the cohort. Only 6.82% and 0.5% of patients had LK and SLK at baseline, while the incidence increased and kept in 25%-32% and 5.5%-8.2% after PD. Both LK (HR 1.437, 95% CI 1.014-2.038, P = .042) and SLK (HR 2.021, 95% CI 1.429-2.857, P < .001) did correlate to peritonitis after adjusted analyses, while only SLK remained the significance at each follow-up point. The LK/SLK durations were 6 (3-12) and 6 (3-6) months, and only longer SLK duration correlated with peritonitis after adjusted analyses. After categorised, those LK durations more than 6 months and SLK durations more than 3 months presented a significant association with peritonitis. Of the patients who suffered from both hypokalemia and peritonitis, 70.4% patients' LK times were earlier than peritonitis time, while most SLK times (62.7%) were later. SLK also correlated with combined endpoint. CONCLUSIONS Hypokalemia degree and duration were tightly associated with peritonitis. Hypokalemia might be a causal factor of peritonitis, while peritonitis might also aggravate hypokalemia. We should manage SK as much as possible and avoid hypokalemia, especially serious hypokalemia in clinic practice.