title: Diabetic retinopathy predicts all-cause mortality and cardiovascular events in both type 1 and 2 diabetes: meta-analysis of observational studies.
abstract: OBJECTIVE
  The prognostic significance of diabetic retinopathy (DR) for death and cardiovascular (CV) outcomes is debated. We investigated the association of DR with all-cause mortality and CV events in patients with diabetes by a systematic review and meta-analysis.
  
  
  METHODS
  The electronic databases Medline and Embase were searched for cohort studies that evaluated DR in type 2 or type 1 diabetic patients and reported total mortality and/or fatal and nonfatal CV events, including myocardial infarction, angina pectoris, coronary artery bypass graft, ischemic changes on a conventional 12-lead electrocardiogram, transient ischemic attack, nonfatal stroke, or lower leg amputation. Data extraction was performed by two reviewers independently. Pooled effect estimates were obtained by using random-effects meta-analysis.
  
  
  RESULTS
  The analysis included 20 studies that fulfilled the inclusion criteria, providing data from 19,234 patients. In patients with type 2 diabetes (n = 14,896), the presence of any degree of DR increased the chance for all-cause mortality and/or CV events by 2.34 (95% CI 1.96-2.80) compared with patients without DR. In patients with type 1 diabetes (n = 4,438), the corresponding odds ratio was 4.10 (1.50-11.18). These associations remained after adjusting for traditional CV risk factors. DR was also predictive of all-cause mortality in type 2 diabetes (odds ratio 2.41 [1.87-3.10]) and type 1 diabetes (3.65 [1.05-12.66]).
  
  
  CONCLUSIONS
  The presence of DR was associated with an increased risk of all-cause mortality and CV events in both type 2 and type 1 diabetic patients.
authors.affiliation: Division of Endocrinology, Hospital de Clínicas de Porto Alegre, Universidade Federal do RioGrande do Sul, Porto Alegre, Rio Grande do Sul, Brazil. carolinekkramer@gmail.com
authors.forename: Caroline K
authors.initials: CK
authors.lastname: Kramer
authors.forename: Ticiana C
authors.initials: TC
authors.lastname: Rodrigues
authors.forename: Luis H
authors.initials: LH
authors.lastname: Canani
authors.forename: Jorge L
authors.initials: JL
authors.lastname: Gross
authors.forename: Mirela J
authors.initials: MJ
authors.lastname: Azevedo
mesh_terms: D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000453:epidemiology / Q000503:physiopathology*; D006801:Humans