Incidence of hyperkalemia in patients on maintenance hemodialysis and risk-factor analysis

Objective: For patients on maintenance hemodialysis, hyperkalemia has now been lowered from 5.5 mmol/L to 5.0 mmol/L. We undertook this study in order to clarify the incidence of hyperkalemia under this new criterion, to determine the associated risk factors, and to provide guidance for the prevention of hyperkalemia. Methods: Data from all hemodialysis centers of Foshan City were included in a crosssectional survey, the overall incidence of hyperkalemia was determined and the risk factors were analyzed. Results: Our study comprised 2582 patients from 34 dialysis centers. 107 patients (4.14%) with serum potassium levels at or below 3.5 mmol/L, 1473(57.05%) with serum potassium levels between 3.5 and 5.0 mmol/L, 494 (19.13%) with serum potassium levels between 5.0 and 5.5 mmol/L, and 508 (19.67%) with serum potassium levels above 5.5 mmol/L. The Incidence of hyperkalemia was significantly greater under the new criterion than the old criterion (38.81% vs 19.67%, P <0.001). We divided the patients into non-hyperkalemia and hyperkalemia groups by the new criterion. Patients in the hyperkalemia group were younger, higher body-mass indices (BMIs), higher systolic and diastolic blood pressures, higher serum creatinine, higher serum blood urea nitrogen (BUN), lower pre-dialysis carbon dioxide combining power (CO2CP), and less residual urine volume(RUV), higher proportion of using angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs). Through multiple logistic regression analysis, we found that systolic blood pressure, RUV, ACEI/ARB usage, pre-dialysis CO2CP, and pre-dialysis BUN were independent risk factors for hyperkalemia. Conclusion: In the Foshan area, the incidence of hyperkalemia in patients on maintenance hemodialysis is very high. Under the new criterion, the diagnosis rate of hyperkalemia would be significantly increased. Moreover, high systolic blood pressure,decreased RUV, decreased pre-dialysis CO2CP, increased predialysis BUN, and the use of ACEIs/ARBs were found to be independent risk factors for hyperkalemia.