Role of dietary salt intake in posttransplant hypertension with tacrolimus-based immunosuppression

Dietary salt is an important contributor to hypertension in the general population. While its role in cyclosporine-induced hypertension is minimal, its role in tacrolimus-based immunosuppression has not been defined. We measured the 24-hour urine sodium excretion as an estimate of intake in a group of stable renal transplant recipients on tacrolimus (N = 143) who had serum creatinine fluctuations <20% during the preceding 3 months. Average clinic-measured blood pressure (BP) from before and after the 24-hour urine collection was computed. Patients with recent changes in antihypertensive medications were excluded. Average systolic BP was 126 +/- 14 and diastolic BP 76 +/- 7 mm Hg. Urine sodium was 162.6 +/- 70 mmol/d (range 50 to 351), and the sodium/creatinine ratio was 15.4 +/- 6.4. There was no correlation between urine sodium excretion and either systolic or diastolic BP (R = 0.07 and R = 0.05, P = NS) or the sodium/creatinine and systolic/diastolic BP (R = 0.13, R = 0.11, P = NS). By multiple linear regression only weight and urine protein were independently associated with both systolic BP (P < .0001 for each) and diastolic BP (P < .05 for each). In conclusion, there is no appreciable influence of dietary salt intake on BP under tacrolimus-based immunosuppression. Restricting dietary salt intake in these patients cannot be recommended at the current time.