Association between Serum Amyloid A Levels and Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Background: To date, consistent data have not been reported on the association between serum amyloid A (SAA) levels and type 2 diabetes mellitus (T2DM). The purpose of this study was to systematically summarize their relationship. Methods: Databases including PubMed, Cochrane Library, Embase, Web of Science, and MEDLINE were searched until August 2021. Cross-sectional and case-control studies were included. Results: Twenty-one studies with 1,780 cases and 2,070 controls were identified. SAA levels were significantly higher in T2DM patients than in healthy groups (standardized mean difference [SMD], 0.68; 95% confidence interval [CI], 0.39 to 0.98). A subgroup analysis showed that the mean age of participants and the continent that participants were from were related to differences in SAA levels between cases and controls. Furthermore, in T2DM patients, SAA levels were positively associated with body mass index (r=0.34; 95% CI, 0.03 to 0.66), triglycerides (r=0.12; 95% CI, 0.01 to 0.24), fasting plasma glucose (r=0.26; 95% CI, 0.07 to 0.45), hemoglobin A1c (r=0.24; 95% CI, 0.16 to 0.33), homeostasis model assessment for insulin resistance (r=0.22; 95% CI, 0.10 to 0.34), C-reactive protein (r=0.77; 95% CI, 0.62 to 0.91), and interleukin-6 (r=0.42; 95% CI, 0.31 to 0.54), but negatively linked with high density lipoprotein cholesterol (r=-0.23; 95% CI, -0.44 to -0.03). Conclusion: The meta-analysis suggests that high SAA levels may be associated with the presence of T2DM, as well as lipid metabolism homeostasis and the inflammatory response.