Medical nutrition therapy provided by a dietitian improves outcomes in adults with prehypertension or hypertension: a systematic review and meta-analysis

Background: Hypertension is an important risk factor for cardiovascular disease (CVD). Interventions with dietitians can help modify dietary intake and reduce hypertension risk.

Objectives: We aimed to examine the following research question: In adults with prehypertension or hypertension, what is the effect of medical nutrition therapy (MNT) provided by a dietitian on blood pressure (BP), CVD risk and events, and anthropometrics compared with 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 was assessed using 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 method.

Results: Forty articles representing 31 RCTs were included and analyzed. MNT provided by a dietitian may reduce systolic [mean difference (MD): -3.63 mmHg; 95% confidence interval (CI): -4.35, -2.91 mmHg] and diastolic (MD: -2.02 mmHg; 95% CI: -2.56, -1.49 mmHg) BP (P < 0.001) and body weight (MD: -1.84 kg; 95% CI: -2.72, -0.96 kg; P < 0.001) and improve antihypertensive medication usage, relative risk of stroke (MD: 0.34; 95% CI: 0.14, 0.81; P = 0.02), and CVD risk score [standardized mean difference (SMD): -0.20; 95% CI: -0.30, -0.09; P < 0.001] compared with control participants, and COE was moderate. Additionally, MNT may reduce arterial stiffness (SMD: -0.45; 95% CI: -0.71, -0.19; P = 0.008) and waist circumference (SMD: -1.18 cm; 95% CI: -2.00, -0.36; P = 0.04), and COE was low. There was no significant difference in risk of myocardial infarction between groups. Dietitian interventions reduced BP and related cardiovascular outcomes for adults with prehypertension or hypertension.

Conclusions: 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. This review was registered at PROSPERO as CRD42022351693.