Abstract
BackgroundRetinol binding protein 4 (RBP4) has been proposed to play a role in the pathophysiology of coronary artery disease (CAD), but previous findings on the association of RBP4 levels with CAD are inconsistent.MethodsA meta-analysis based on observational studies was conducted to evaluate the association between circulating RBP4 levels and CAD. Databases including PubMed, Web of Science, Embase, Google Scholar and ClinicalTrials.gov database were searched for eligible studies published up to 12 July 2021. Standard mean differences (SMDs) with 95% confidence intervals (CIs) were calculated using the inverse variance heterogeneity (IVhet) and random-effects model for data with moderate and high heterogeneity (I2 > 30%) and data with low heterogeneity were analysed using a fixed-effects model (I2 ≤ 30%). Moreover, a bias-adjusted quality-effects model was generated, and the prediction interval was also calculated under the random-effects model.ResultsTwo nested case-control studies, one cohort study and twelve case–control studies with a total of 7111 participants were included. Circulating RBP4 levels in patients with CAD were comparable to those in the controls under the IVhet model (SMD: 0.25, 95% CI: − 0.29-0.79, I2: 96.00%). The quality-effects model produced consistent results. However, the association turned to be significant under the random-effect model (SMD: 0.46, 95% CI: 0.17–0.75, I2: 96.00%), whereas the 95% predictive interval (PI) included null values (95% PI: − 0.82-1.74). Subgroup analyses illustrated a positive relationship between CAD and RBP4 levels in patients with complications (SMD: 1.34, 95% CI: 0.38–2.29, I2: 96.00%). The meta-regression analysis revealed that the mean BMI of patients (P = 0.03) and complication status (P = 0.01) influenced the variation in SMD.ConclusionsThere was low-quality evidence that patients with CAD exhibited similar circulating RBP4 levels compared with controls, and high inter-study heterogeneity was also observed. Thus, RBP4 might not be a potential risk factor for CAD. Comparisons among different subtypes of RBP4 with larger sample size are needed in the future.
Highlights
Coronary artery disease (CAD), the most frequent cardiovascular disease, is the leading cause of mortality and morbidity worldwide [1]
Researchers have not clearly determined whether increased Retinol binding protein 4 (RBP4) levels are associated with the risk of coronary artery disease (CAD), as most studies have reported similar results that elevated circulating RBP4 levels are related to CAD [7–11], whereas a nonsignificant or even negative relationships between RBP4 levels and CAD were documented in other studies [12–14]
A meta-analysis was conducted to assess the relationship between circulating RBP4 levels and CAD, but the study population was limited to Chinese individuals, which restricted the generalization of the results to other populations [16]
Summary
Coronary artery disease (CAD), the most frequent cardiovascular disease, is the leading cause of mortality and morbidity worldwide [1]. Researchers have not clearly determined whether increased RBP4 levels are associated with the risk of CAD, as most studies have reported similar results that elevated circulating RBP4 levels are related to CAD [7–11], whereas a nonsignificant or even negative relationships between RBP4 levels and CAD were documented in other studies [12–14]. A meta-analysis was conducted to assess the relationship between circulating RBP4 levels and CAD, but the study population was limited to Chinese individuals, which restricted the generalization of the results to other populations [16]. Retinol binding protein 4 (RBP4) has been proposed to play a role in the pathophysiology of coronary artery disease (CAD), but previous findings on the association of RBP4 levels with CAD are inconsistent
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