Pre-operative serum potassium as a risk factor for early complications after renal transplantation: a cohort study

B.C.S. de Vries, S.P. Berger, S.J.L. Bakker, M.H. de Borst, M.F.C. de Jong

Friday 16 march 2018

10:25 - 10:30h at Willem Burger Foyer

Categories: Clinical, Session (poster)

Parallel session: Poster session 7: Clinical

Introduction

In current practice, no guidelines exist how to handle pre-transplantation serum potassium (K⁺) in renal transplant recipients (RTR). Since serum K⁺ abnormalities are common among patients with chronic kidney disease and are associated with higher rates of death, major adverse cardiac events and hospitalisation in this population, pre-transplantation K⁺ seems an important parameter for evaluation in RTR. The aim of this study is to examine the relation between pre-operative serum K⁺ and complications within 48 hours after renal transplantation, comprising interventions to resolve hyperkalaemia. The secondary objective is to determine a cut-off level for pre-operative serum K⁺.

Methods

This cohort study included all RTR in our centre in 2014. Primary endpoint was the prevalence of dialysis or use of K⁺ lowering medication (defined as K⁺ interventions) to resolve hyperkalaemia within 48 hours post renal transplantation in relation to pre-operative serum K⁺ concentrations, using binary multivariate logistic regression. The optimal cut-off level for pre-operative serum K⁺ with respect to K⁺ interventions was determined using receiver operating curves. Clinical, biochemical and demographic parameters were recorded on admission and until 48 hours after surgery.

Results

151 recipients were included, of whom 51 (33,8%) patients received one or more intervention to resolve hyperkalaemia within 48 hours after transplantation. Pre-operative serum K⁺ was nominally higher in patients with post-operative K⁺ interventions (4.6 +/- 1.10 mmol/L) than in patients with no post-operative K⁺ interventions (4.4 +/- 0.9 mmol/L, p=NS). Multivariate analysis showed a significant positive relationship between pre-operative serum K⁺ and K⁺ interventions for both the total cohort (Odds Ratio (OR)=2.2, 95% Confidence Interval (CI)=1.1-4.2, p=0.023) and the subgroup with a living donor graft (OR=8.0, 95% CI=1.1-56.4, p=0.038), but not for patients with a post-mortal donor. A cut-off value of K⁺ > 4.9 mmol/L for patients with a living donor resulted in a sensitivity and specificity of 62.5% and 81.3%, respectively.

Conclusion

This study shows a positive correlation between pre-operative serum K⁺ and interventions to resolve hyperkalaemia within 48 hours post renal transplantation. Pre-operative serum K⁺ > 4.9 predicts a higher prevalence of interventions to resolve hyperkalaemia in patients with a living donor. Further research is recommended to confirm these results.