title: Relationship between C-Reactive Protein Level and Diabetic Retinopathy: A Systematic Review and Meta-Analysis.
abstract: OBJECTIVE
  To date, the relationship between C-reactive protein (CRP) level and diabetic retinopathy (DR) remains controversial. Therefore, a systematic review and meta-analysis was used to reveal the potential relationship between CRP level and DR.
  
  
  METHODS
  A systematic search of PubMed, Embase.com, and Web of Science was performed to identify all comparative studies that compared the CRP level of two groups (case group and control group). We defined that diabetic patients without retinopathy and/or matched healthy persons constituted the control group, and patients with DR were the case group.
  
  
  RESULTS
  Two cross sectional studies and twenty case control studies including a total of 3679 participants were identified. After pooling the data from all 22 studies, obvious heterogeneity existed between the studies, so a subgroup analysis and sensitivity analysis were performed. Removing the sensitivity studies, the blood CRP levels in the case group were observed to be higher than those in the control group [SMD = 0.22, 95% confidence interval (CI), 0.11-0.34], and the blood CRP levels in the proliferative diabetic retinopathy (PDR) group were also higher than those in the non-proliferative diabetic retinopathy (NPDR) group [SMD = 0.50, 95% CI, 0.30-0.70].
  
  
  CONCLUSIONS
  The results from this current meta-analysis indicate that the CRP level might be used as a biomarker to determine the severity of DR.
authors.affiliation: Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Song
authors.affiliation: Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.|Tianjin Eye Hospital, Tianjin, China.|Tianjin Key Laboratory of Ophthalmology and Visual Science, Tianjin, China.|Tianjin Eye Institute, Tianjin, China.
authors.forename: Song
authors.initials: S
authors.lastname: Chen
authors.affiliation: Department of Public Health, Xinxiang Medical University, Xinxiang, China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Liu
authors.affiliation: Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Duan
authors.affiliation: Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.
authors.forename: Jiahui
authors.initials: J
authors.lastname: Kong
authors.affiliation: Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China.
authors.forename: Zedong
authors.initials: Z
authors.lastname: Li
mesh_terms: D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D003930:Diabetic Retinopathy / Q000097:blood*; D006801:Humans; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein