Variability of Rates of Hyperkalemia among Patients on Hemodialysis

Orlando—Patients with end-stage renal disease have a high prevalence of cardia arrhythmias and sudden death. Patients more commonly experience hyperkalemia during the long inter-dialytic period, creating an association with increased mortality. Bhupinder Singh, MD, and colleagues recently conducted a prospective, observational study designed to examine the incidence of hyperkalemia, defined as serum potassium >5.0 mEq/L, as well as hypokalemia, and potassium level variability among patients on hemodialysis.

The researchers reported results of the analysis during a poster session at the 2017 NKF Spring Clinical Meetings. The poster was titled Hyperkalemia and Serum Potassium Variability in Patients on Hemodialysis.

The study assessed serial serum potassium levels for 12 days. The primary end point of interest was the incidence of predialysis hyperkalemia after the long inter-dialytic period in patients treated with less than 3K (<3K) dialysate bath (n=179) and in patients treated with 3K or more (≥3K) dialysate bath (n=33). Secondary end points were the incidence of pre-dialysis hyperkalemia in patients in the ≥3K group and cardiac arrhythmias.

Predialysis, the mean potassium serum level in the <3K group was 4.7 mEq/L and 4.5 mEq/L in the ≥3K group. The mean pre-to postdialysis change in serum potassium level was ­–1.4 mEq/L in the 3K group and –0.7 mEq/L in the ≥3K group. Fifty percent of the 3K group had any hyperkalemia after the long inter-dialytic period, compared with 36% in the ≥3K group. Based on mean serum potassium level, 37% of the 3K group had predialysis hyperkalemia after the long inter-dialytic period compared with 21% on the ≥3K group. In patients with hyperkalemia, the range of serum potassium level was 4.0 to 6.6 mEq/L in the 3 K group and 4.9 to 5.8 mEq/L in the ≥3K group. In the 3K group, 79% of patients had post-dialysis hypokalemia compared with 12% in the ≥3K group.

Only 12% of the patients in the overall study cohort had a known history of atrial fibrillation (AF); 51% had AF during the study period. Sixteen percent had serious arrhythmias, defined as ventricular tachycardia or ≥5 second pause.

“Hyperkalemia was common, there were large intra-dialytic potassium changes, and most <3K dialysate patients had post-dialysis hypokalemia. The large serum potassium level variability and high rates of atrial fibrillation and life-threatening arrhythmias in these patients warrant further study,” the researchers said.

Source: Singh B, Block G, Lerma EV, et al. Hyperkalemia and serum potassium variability in patients on hemodialysis. Abstract of a poster presented at the 2017 National Kidney Foundation Spring Clinical Meetings, April 21, 2017, Orlando., Florida.