title: Risk factors for diabetic retinopathy in people with Type 2 diabetes: A case-control study in a UK primary care setting.
abstract: To identify risk factors of diabetic retinopathy (DR) among people with Type 2 diabetes mellitus in UK primary care.
  
  
  
  A case-control study nested in a cohort of incident Type 2 diabetes identified in The Health Improvement Network database from 2000 to 2007. Cases were people with DR (N=7735) and controls were a DR-free sample (N=9395). No age restrictions were applied. Adjusted odds ratios and 95% CIs were estimated.
  
  
  
  21% of DR cases were identified during the first semester after Type 2 diabetes diagnosis. After controlling for delay on the Type 2 diabetes diagnosis, the DR risk increased with the duration of diabetes. DR increased with a mean systolic BP ≥150mmHg (1.18; 1.10-1.27), high alcohol consumption (1.34; 1.11-1.61), glycated haemoglobin (≥75 to <86: 1.14; 1.00-1.31; ≥86 to <97mmol/mol: 1.25; 1.07-1.45; ≥97mmol/mol: 1.21; 1.07-1.37), microalbuminuria (1.16; 1.06-1.27), and retinal vein occlusion (2.47; 1.67-3.66). Glaucoma and retinal arterial occlusion showed an OR of 0.71 (0.60-0.84) and 0.63 (0.40-1.01), respectively. HDL ≥1.55mmol/l (0.88; 0.80-0.98), high triglycerides (2.3-5.6mmol/l: 0.90; 0.82-0.99; >5.6mmol/l: 0.85; 0.64-1.13) or smoking (0.89; 0.81-0.97) had a slightly reduced DR risk. Users of hypoglycaemic agents had an increased DR risk.
  
  
  
  Some DR cases were identified near the diabetes diagnosis date suggesting that a delayed diabetes diagnosis is still common. Glaucoma, retinal arterial occlusion and high HDL levels were inversely associated with DR, while retinal vein occlusion, alcohol and other well-known risk factors were positively associated.
authors: Centro Español de Investigación Farmacoepidemiológica, Madrid, Spain. Electronic address: elisaceife@gmail.com.
authors: Elisa
authors: E
authors: Martín-Merino
authors: DS&E - Global Clinical Epidemiology, Novartis Farmaceutica S.A., Barcelona, Spain.
authors: Joan
authors: J
authors: Fortuny
authors: DS&E - Global Clinical Epidemiology, Novartis Farmaceutica S.A., Barcelona, Spain.
authors: Elena
authors: E
authors: Rivero-Ferrer
authors: Institute of Medicine, University of Gothenburg, Gothenburg, Sweden; Department of Medicine, NU-Hospital Organization, Uddevalla, Sweden.
authors: Marcus
authors: M
authors: Lind
authors: Centro Español de Investigación Farmacoepidemiológica, Madrid, Spain.
authors: Luis Alberto
authors: LA
authors: Garcia-Rodriguez
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000009:adverse effects / Q000453:epidemiology; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D016208:Databases, Factual; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000453:epidemiology*; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D005901:Glaucoma / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008075:Lipoproteins, HDL / Q000097:blood; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011320:Primary Health Care; D065840:Protective Factors; D012170:Retinal Vein Occlusion / Q000175:diagnosis / Q000453:epidemiology; D018570:Risk Assessment; D012307:Risk Factors; D006113:United Kingdom / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D008075:Lipoproteins, HDL
keywords: Case–control study; Diabetic retinopathy; Primary care; Risk factors; Type 2 diabetes