Lowered circulating apelin is significantly associated with an increased risk for hypertension: A meta-analysis

Apelin is a bioactive peptide manifesting a potent vasodilatory property. In this meta-analysis, we aimed to investigate for the first time whether circulating apelin differed significantly between hypertensive patients and normotensive controls.

Both PubMed and Embase were searched for eligible articles. Eligibility evaluation and data collection were done independently by two investigators. Weighted mean difference (WMD) with 95% confidence interval (CI) was calculated under random-effects model by STATA.

Ten studies were synthesized finally, including 1610 patients and 1105 controls. Overall analysis revealed that circulating apelin was significantly lowered in patients than in controls (WMD = -39.85 pg/mL, 95% CI: -65.56 to -14.15; P = 0.002), with significant heterogeneity (I² = 89.4%). By race, patients had lower circulating apelin than controls in Caucasian populations (WMD = -79.82 pg/mL, 95% CI: -105.80 to -53.85; P < 0.001), without heterogeneity (I²=0.0%), while no significance was observed in Chinese and African-Americans. Further grouping studies by source of controls found a significant reduction in circulating apelin in studies with hospital-based controls (WMD = -96.28 pg/mL, 95% CI: -129.67 to -62.88; P < 0.001) (I² = 49.4%), but not in studies with population-based controls.

Via a meta-analysis of 10 studies and on 2715 subjects, our findings demonstrated that lowered circulating apelin was significantly associated with an increased risk for hypertension, especially in Caucasian populations.