Both low and high serum potassium levels are associated with increased mortality risks among patients starting on peritoneal dialysis (PD), according to a recent study.
In addition, the study identified a possible racial/ethnic difference in mortality risk associated with high serum potassium levels in this patient population.
In a study of 17,664 patients who started PD at a large US dialysis organization from January 1, 2007 to December 31, 2011, a team led by Elani Streja, MPH, PhD, of the University of California Irvine, found that hypokalemia was associated with both all-cause and arrhythmia-related mortality regardless of race or ethnicity, and hyperkalemia was associated with both mortality outcomes in non-Hispanic blacks and whites and neither outcome in Hispanics.
The investigators defined hypokalemia and hyperkalemia as serum potassium levels below 3.5 and above 5.0 mEq/L, respectively.
Overall, compared with a reference serum potassium value of 4 mEq/L, levels of 2.5, 3.5, 5.0, and 6.0 mEq/L were associated with approximately 4.2-, 1.4-, 1.2-, and 1.6-fold increased risks of all-cause mortality, respectively, and 4.4-, 1.4-, 1.2-, and 1.6-fold increased risks of arrhythmia-related mortality, respectively, in case-mix adjusted models, Dr Streja and her colleagues reported in the American Journal of Nephrology.
Among non-Hispanic blacks, serum potassium values of 5.0 and 6.0 mEq/L (hyperkalemia) were associated with 1.3- and 1.5-fold increased risks of all-cause mortality, respectively, and 1.7- and 2.7-fold increased risks of arrhythmia-related mortality, respectively. Among whites, these potassium values were associated with 1.2- and 1.8-fold increased risks of all-cause mortality, respectively, and 1.2- and 1.8-fold increased risks of arrhythmia-related mortality, respectively. Hyperkalemia was not associated with all-cause or arrhythmia-related deaths among Hispanics.
“Further studies are needed to demonstrate whether different strategies should be followed in the management of serum potassium levels according to race/ethnicity,” the authors noted.
Eriguchi R, Obi Y, Soohoo M, et al. Racial and ethnic differences in mortality associated with serum potassium in incident peritoneal dialysis patients [published online September 19, 2019]. Am J Nephrol. doi: 10.1159/000502998