Serum Potassium Levels Pretransplant and Outcomes Posttransplant

Austin—High risks of serum potassium abnormalities are common among patients undergoing hemodialysis; hyperkalemia is particularly common in that patient population. Previous studies have shown that patients with hypo- and hyperkalemia are at increased risk for mortality compared with patients with normokalemia.

Potassium regulation can be achieved with kidney transplantation to varying degrees; however, there are few available data on whether the increased mortality associated with dyskalemia in patients on dialysis can be mitigated with kidney transplantation. Austin Hu, MD, and Wolfgang Winkelmayer, MD, MPH, ScD, both at the Baylor College of Medicine in Houston, Texas, conducted a study to examine the incidence of death from any cause as well as nonfatal and all-cause allograft loss among patients who received a first kidney transplant from 2006 to 2011. Results of the study were reported during a poster session at the NKF 2018 Spring Clinical Meetings in a poster titled Pre-transplant Serum Potassium Concentration and Kidney Transplant Outcomes.

The cohort included 10,388 patients in a large dialysis organization who had one or more serum potassium concentrations measured during <30 days prior to kidney transplant surgery. Potassium concentrations were divided into three categories: (1) low, <3.5 mmol/L; (2) normal, 3.5-5.0 mmol/L; and (3) high >5.0 mmol/L. Cox regression models were used to estimate the association between pretransplant serum potassium concentration and all-cause mortality, nonfatal allograft loss, and all-cause allograft loss. Adjustments for demographic characteristics, comorbidities, transplant variables, and laboratory indicators were made.

Of the total cohort, 65% had normokalemia, 2.2% were hypokalemic, and 32.9% were hyperkalemic. There were 1033 deaths and 880 nonfatal allograft losses over up to 26,875 person-years. Compared with patients with eukalemia, rates of mortality were similar in patients with hypokalemia or hyperkalemia (hazard ratio [HR, 0.86; 95% confidence interval [CI], 0.54-1.38; HR, 1.11; 95% CI, 0.89-1.40, respectively). The similarities remained even in fully adjusted models. Pretransplant serum potassium concentration was not associated with allograft loss, with or without death as a cause.

“The association of dyskalemia with increased morality in hemodialysis patients is mitigated with kidney transplantation and indicates no further risk in these patients. This suggests that the restoration of kidney function can reverse (to a degree) factors that lead to serum potassium derangements and increased mortality,” the researchers concluded.

Source: Hu A, Winkelmayer W. Pre-transplant serum potassium concentration and kidney transplant outcomes. Abstract of a poster presented at the National Kidney Foundation 2018 Spring Clinical Meetings, April 10-14, 2018, Austin, Texas.