Lower dry weight is associated with post-hemodialysis hypokalemia.

Introduction: Serum potassium levels <3 mEq/L at post-hemodialysis (HD) are closely associated with poor prognosis. This study aimed to identify high-risk patients with post-HD hypokalemia after regular HD using potassium (2 mEq/L) dialysate solution.

Methods: A total of 129 patients receiving HD and 1121 HD sessions were enrolled in this single-center retrospective cross-sectional study. The association of post-HD hypokalemia less than 3 mEq/L with patient background, as well as each dialysis session was investigated.

Results: Approximately 16% of 129 patients and 10% of 1121 sessions showed post-HD hypokalemia. In per-patient analysis, more inpatients and lower dry weight were found in the hypokalemia group compared with the non-hypokalemia group. Logistic regression analysis indicated that lower dry weight was significantly associated with higher risk of hypokalemia independent of inpatients (p < 0.01). To determine the best cut-off value of pre-HD potassium for identifying post-HD hypokalemia, receiver operating curve analysis was performed in per-session analysis. The results showed that the optimal pre-HD potassium cut-off value was 4.2 mEq/L. In the 250 sessions below the optimal cut-off value for post-HD hypokalemia development, 28.8% of sessions with potassium correction showed post-HD hypokalemia, compared to 40.8% of sessions without potassium correction. Although numerically lower, the difference did not reach statistical significance (p = 0.125).

Conclusion: Our results indicated that a relatively lower dry weight was more likely to complicate post-HD hypokalemia. Potassium supplementation for high-risk patients during HD sessions may be needed to prevent post-HD hypokalemia.