The association between apolipoprotein A-1 plasma level and premature coronary artery disease: A systematic review and meta-analysis.

BACKGROUND Apolipoprotein A-1 (Apo A-1) is a constituent of high-density lipoprotein (HDL) and emerging evidences put forward a potential association between Apo A-1 plasma levels and premature coronary artery disease (pCAD). The aim of the present study is to gather relative literature and perform a systematic review and meta-analysis regarding the association between serum ApoA-1 levels and pCAD. METHODS Medline (via PubMed), Scopus, Embase and Web of Science databases were searched from the inception of databases until December 7, 2020. All articles reporting the plasma levels of ApoA-1 in patients with pCAD and the control group were included. A meta-analysis with pooled standardised mean difference (SMD) and 95% confidence interval (95% CI) was reported. Subgroup analyses were done based on the observed heterogeneity in results. RESULTS Seventeen case-control studies were included. ApoA-1 plasma level was calculated to be lower in pCAD patients compared with the control group (SMD: -0.67; 95% CI: -0.48 to -0.86; P < .001). The subgroup analysis and meta-regression showed that the variation in gender distribution, the development level of the target population's country and quality score of included studies were the main sources of heterogeneity. It was observed that the relationship was only significant in the developed countries (P < .001). Also, the heterogeneity was reduced when the analysis was limited to males (I2 = 57.2%) and females only (I2 = 26.0%). CONCLUSION In conclusion, there seems to be a significant association between the serum levels of ApoA-1 and pCAD. However, all of the included studies had a case-control design and since there is no good quality and prospective cohort studies included, reliability of the current evidence is debatable. Therefore, further well-designed cohort studies are required to assess the impact of serum ApoA-1 reduction on pCAD onset.