#654 Double-blind randomised controlled trial of nitrate-replete beetroot juice on blood pressure in autosomal dominant polycystic kidney disease

Abstract

Abstract Background and Aims Hypertension in autosomal dominant polycystic kidney disease is in part mediated by reduced polycystin-regulated nitric oxide synthase activity. In this study, the hypothesis that beetroot juice (BRJ, a rich natural dietary source of nitrate) reduces blood pressure in hypertensive autosomal dominant polycystic kidney disease (ADPKD) patients was evaluated. Method Stable hypertensive patients (n = 60) with ADPKD (eGFR > 30 mL/min/1.73 m2) were randomised (1:1) to either nitrate-replete BRJ (400 mg nitrate/day) or nitrate-deplete BRJ for 4 weeks. Patients and investigators were blinded to the allocation. The primary endpoints were changes in systolic and diastolic clinic blood pressure between baseline and at 4 weeks. The secondary endpoints were serum nitrate/nitrite levels, daily home blood pressure and albuminuria. Results Serum nitrate/nitrite increased 3.6-fold in the nitrate-replete compared to the nitrate-deplete group (p < 0.01). Both groups had similar baseline characteristics. After 4 weeks, clinic systolic and diastolic blood pressure significantly declined in both nitrate-replete and nitrate-deplete BRJ groups compared to baseline (systolic blood pressure: −5.36 vs. −7.65 mmHg; diastolic blood pressure: −3.55 vs. −2.73 mmHg; P < 0.05). Other secondary endpoints, treatment adherence, discontinuations and adverse effects were similar in both groups. Conclusion Increasing serum nitrate with BRJ did not lower blood pressure in hypertensive patients with ADPKD. The blood pressure reduction in both groups could be due to non-nitrate phytonutrients in BRJ and/or placebo-associated effects. These data further emphasise the importance of healthy eating and regular monitoring of blood pressure in patients with ADPKD.