Medical Nutrition Therapy Provided by a Dietitian Improves Outcomes in Adults with Pre-Hypertension or Hypertension: A Systematic Review and Meta-Analysis

Background Hypertension is an important risk factor for cardiovascular disease. Interventions with dietitians can help modify dietary intake and reduce hypertension risk. Objective To examine the research question: In adults with pre-hypertension or hypertension, what is the effect of medical nutrition therapy (MNT) provided by a dietitian on blood pressure (BP), cardiovascular risk and events and anthropometrics compared to standard care or no intervention? Methods MEDLINE, CINAHL and Cochrane Central databases were searched for randomized controlled trials (RCTs) published in peer-reviewed journals from 1985-2022. Risk of bias (RoB) was assessed using the version 2 of the Cochrane tool for RCTs. Meta-analyses were conducted using the DerSimonian-Laird random-effects model. Certainty of evidence (COE) was assessed for each outcome using the Grading of Recommendations, Assessment, and Evaluation (GRADE) method. Results Forty articles representing 31 RCTs were included and analyzed. MNT provided by a dietitian likely reduces systolic [Mean Difference (MD): -3.63 mmHg (95% confidence interval (CI): -4.35, -2.91)] and diastolic [-2.02 mmHg (-2.56, -1.49)] BP (p<0.001) and body weight [-1.84 kg (-2.72, -0.96), p<0.001], and improves anti-hypertensive medication usage, relative risk of stroke [0.34 (0.14, 0.81), p=0.02] and CVD risk score [standardized mean difference (SMD): -0.20 (-0.30, -0.09), p<0.001] compared to control participants, and COE was moderate. Additionally, MNT may reduce arterial stiffness [SMD: -0.45 (-0.71, -0.19), p=0.008] and waist circumference [-1.18 cm (-2.00, -0.36), p=0.04], and COE was low. There was no significant difference in risk for myocardial infarction between groups. Dietitian interventions reduced BP and related cardiovascular outcomes for adults with pre-hypertension or hypertension. Conclusion Dietitians play a critical role in improving cardiometabolic risk factors for adults with elevated BP; thus, improved payment for and access to MNT services has the potential to significantly impact public health. Registration ID and URL This systematic review was registered in the International Prospective Register of Systematic Reviews: PROSPERO# CRD42022351693 (https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022351693).