Salt intake and hypertension in renal transplant patients

Background: Dietary salt restriction is currently widely recommended as an important non-pharmacological measure for the treatment of hypertension. However, the relationship between dietary salt intake and post-transplant hypertension has not been extensively investigated. Patients and methods: We examined the relationship between dietary salt intake and the prevalence of hypertension in 129 renal transplant patients with stable allograft function (serum creatinine < 400 mu mol/l, variation in serum creatinine during the preceding two months < 20%). Salt intake was assessed by measuring 24-hour urinary excretion of sodium on an unrestricted diet. Hypertension was defined based on the prescription of antihypertensive medication, and the number of antihypertensive drugs was considered a surrogate marker for severity of hypertension. Patients were divided into tertiles based on urinary sodium excretion and analyzed by chi(2)-testing. Results: The prevalence of hypertension was 74% and the mean sodium excretion was 178 mmol/d (range: 56 to 603), There was no statistical difference in the frequency of antihypertensive medication between patients with low (76%, U-Na = 107 mmol/d), medium (73%, U-Na = 178 mmol/d), or high sodium (73%, U-Na = 272 mmol/d) excretion. Furthermore, the number of antihypertensive drugs (in treated patients) was similar between the tertiles. There was also no correlation between urinary sodium excretion and systolic (r = -0.05) or diastolic (r = 0.08) blood pressure levels. Conclusion: We conclude that dietary salt intake in transplant patients with stable allograft function is higher than currently recommended. There is, however, no relationship between salt intake and the prevalence of hypertension in these patients. These data do not support the hypothesis that the prevalence or severity of post-transplant hypertension is markedly affected by dietary salt intake.