Effect of dietary sodium restriction on blood pressure in type 2 diabetes: A meta-analysis of randomized controlled trials

Abstract

AimsAlthough current guidelines recommend reduction of salt intake in patients with diabetes, the benefits of reducing salt intake in people with type 2 diabetes mellitus (T2DM) lack clear evidence. Therefore, we performed a meta-analysis of available randomized controlled trials (RCTs) of sodium restriction and blood pressure (BP) in patients with T2DM. Data synthesisWe performed a systematic search of the online databases that evaluated the effect of dietary sodium restriction on BP in patients with T2DM. Sodium intake was expressed by 24 h urinary sodium excretion (UNaV). Q statistics and I2 were used to explore between-study heterogeneity. A random-effects model was used in the presence of significant heterogeneity; otherwise, a fixed-effects model was applied. Eight RCTs with 10 trials (7 cross-over and 3 parallel designs) were included in the meta-analysis. Compared with ordinary sodium intake, dietary sodium restriction significantly decreased UNaV (weighted mean difference, WMD: −38.430 mmol/24 h; 95% CI: −41.665 mmol/24 h to −35.194 mmol/24 h). Sodium restriction significantly lowered systolic BP (WMD: −5.574 mm Hg; 95% CI: −8.314 to −2.834 mm Hg; I2 = 0.0%) and diastolic BP (WMD: −1.675 mm Hg; 95% CI: −3.199 to −0.150 mm Hg; I2 = 0.0%) with low heterogeneity among the studies. No publication bias was found from Begg's and Egger's tests. ConclusionsSodium restriction significantly reduces SBP and DBP in patients with T2DM.