Repeated administration of inorganic nitrate lowers blood pressure

Repeated administration of inorganic nitrate results in a reduction of peripheral and central blood pressure (BP), a study has found, noting that the results seem to be driven by the beneficial effects in healthy and hypertensive individuals.

The authors searched Medline, Embase, and the Cochrane Library through 2 July 2019 for randomized controlled trials with at least 3 days’ treatment of inorganic nitrate on BP and arterial stiffness in individuals with or without elevated cardiovascular disease risk.

Relevant study data were extracted by two independent reviewers and were pooled using the generic inverse variance method with random-effects model. Results were expressed as mean differences (MDs) with 95 percent confidence intervals (CIs). Finally, Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess certainty in evidence.

Forty-seven trials, including a total of 1,101 participants, met the eligibility criteria. Inorganic nitrate administration led to a significant reduction in systolic (S)BP (MD, –2.91 mm Hg, 95 percent CI, –3.92 to –1.89; I², 76 percent), diastolic (D)BP (MD, –1.45 mm Hg, 95 percent CI, –2.22 to –0.68; I², 78 percent), central SBP (MD, –1.56 mm Hg, 95 percent CI, –2.62 to –0.50; I², 30 percent), and central DBP (MD, –1.99 mm Hg, 95 percent CI, –2.37 to –1.60; I², 0 percent).

On the other hand, the treatment had no effect on 24-h BP, augmentation index, or pulse wave velocity (PWV). Certainty in evidence was moderate for central BP and PWV, and low for peripheral BP, 24-h BP, and augmentation index.

“More studies are required to increase certainty in the evidence,” the authors said.