The role of dietary cations in the blood pressure of renal transplant recipients.

Background: The role of dietary cations in hypertension has been evaluated in the general population and selected subgroups, but its contribution to blood pressure (BP) elevations in patients with functional renal allografts has not been critically examined.

Methods: After counseling based on Dietary Approaches to Stop Hypertension (DASH) guidelines, we measured timed 24-h urine excretion rates of sodium, potassium, calcium, and magnesium as a surrogate for their dietary intake, in 244 stable adult single-organ renal transplant recipients, correlating these with averaged blinded clinic-measured BP values. Multiple linear regression analysis adjusting for factors affecting BP in transplant recipients was performed.

Results: There was no correlation between systolic (SBP) or diastolic pressure (DBP) and 24-h urine excretion rates of each cation. There was no BP difference between patients receiving cyclosporine and tacrolimus (127/77 vs. 129/78 mmHg, p = 0.38), or in cation excretion except for calcium (2.85 +/- 2.0 vs. 2.90 +/- 2.8, p = 0.002). Protein excretion (p < 0.0001), age (p = 0.002), and weight (p = 0.04) were positively associated with SBP, while only weight (p = 0.01) was associated with DBP by multivariate analysis.

Conclusion: Dietary cation intake is not significantly associated with BP in renal transplant recipients. These data do not support recommendations to alter dietary cation intake as part of the management of post-transplantation hypertension.