Abstract: Objective  To investigate the expression levels of serum amyloid A(SAA) and vascular endothelial growth factor(VEGF) in patients with rheumatoid arthritis(RA) and their roles in different disease activities in RA patients. 
Methods A total of 98 RA patients treated in our hospital and 45 healthy controls were collected. According to disease activity score 28(DAS28), RA patients were divided into a high activity group(n=43), a moderate activity group(n=34), and a low activity and disease remission group(low activity + disease remission, n=21). Spearman correlation was used to analyze the correlation between serum SAA, VEGF levels and clinical indicators. Receiver operating characteristic(ROC) curve was used to analyze the diagnostic value of SAA and VEGF in patients with moderate to high activity RA. 
Results The expression levels of SAA and VEGF in RA group were significantly higher than those in control group. With the increase of disease activity, the expression levels of SAA and VEGF were significantly increased. The expression levels of SAA and VEGF in the high activity group were significantly higher than those in the healthy control group and the low-moderate activity group(P＜0.05). Spearman correlation analysis showed that the expression levels of SAA and VEGF were positively correlated with the number of joint tenderness, joint swelling, ESR and DAS28 scores(all P＜0.05). The ROC curve showed that SAA and VEGF had a predictive value for patients with moderate to high activity RA(P＜0.05), and the combined diagnosis of SAA and VEGF had the highest predictive value for patients with moderate to high activity RA, and the area under the ROC curve(AUC) was 0.871. 
Conclusion Serum SAA and VEGF levels are involved in the immune-inflammatory regulation of RA, which can be used as potential biomarkers to evaluate the activity of RA and contribute to the monitoring and evaluation of RA.

Key words: arthritis, rheumatoid, serum amyloid A protein, vascular endothelial growth factors