title: Progression of diabetic retinopathy after bariatric surgery.
abstract: OBJECTIVE
  To assess the impact of bariatric surgery on the progression of diabetic retinopathy in patients with Type 2 diabetes.
  
  
  METHODS
  We conducted a retrospective, observational study of patients with Type 2 diabetes who underwent bariatric surgery between 1 January 2001 and 31 December 2012 and had hospital-based retinal screening records. Data were collected from four surgical centres. Those who had pre-operative retinal screening and at least one post-operative retinal screen were eligible for analysis. A generalized linear mixed model was used to explore significant clinical predictors on the post-operative grade severity over time, controlling for important baseline characteristics.
  
  
  RESULTS
  Three hundred and eighteen patients were eligible for analysis. Of these, 68.6% had no diabetic retinopathy pre-operatively compared with 18.9%, 8.5% and 4% with a diabetic retinopathy grade of minimal, mild or moderate and higher, respectively. First post-operative retinal screening results showed that after surgery 73% had no change in their diabetic retinopathy grade, 11% regressed and 16% progressed. The probability of having a diabetic retinopathy grade of moderate or higher over time post surgery was significantly associated with the magnitude of HbA1c reduction from pre-surgery HbA1c levels, a shorter post-operative retinal screening duration, more severe pre-operative retinal screening grade, male gender and non-Maori/Pacific ethnicity.
  
  
  CONCLUSIONS
  A higher pre-operative diabetic retinopathy grade, and a large decrease in HbA1c post surgery warrant closer monitoring of diabetic retinopathy after bariatric surgery. Further prospective, randomized studies are required to investigate the gender and ethnic differences found.
authors.affiliation: Department of Medicine, University of Auckland, Auckland, New Zealand.
authors.forename: R
authors.initials: R
authors.lastname: Murphy
authors.affiliation: Department of Statistics, University of Auckland, Auckland, New Zealand.
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: Department of Surgery, North Shore Hospital, Auckland, New Zealand.
authors.forename: M
authors.initials: M
authors.lastname: Booth
authors.affiliation: Department of Surgery, Middlemore Hospital, Auckland, New Zealand.
authors.forename: R
authors.initials: R
authors.lastname: Babor
authors.affiliation: Department of Surgery, Middlemore Hospital, Auckland, New Zealand.|Department of Surgery, University of Auckland, Auckland, New Zealand.
authors.forename: A
authors.initials: A
authors.lastname: MacCormick
authors.affiliation: Department of Surgery, North Shore Hospital, Auckland, New Zealand.
authors.forename: H
authors.initials: H
authors.lastname: Hammodat
authors.affiliation: Department of Surgery, Auckland City Hospital, Auckland, New Zealand.
authors.forename: G
authors.initials: G
authors.lastname: Beban
authors.affiliation: Eye Department, Auckland District Health Board, Auckland, New Zealand.
authors.forename: R M
authors.initials: RM
authors.lastname: Barnes
authors.affiliation: Eye Department, Auckland District Health Board, Auckland, New Zealand.|Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.
authors.forename: A L
authors.initials: AL
authors.lastname: Vincent
mesh_terms: D050110:Bariatric Surgery; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis / Q000601:surgery*; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000601:surgery*; D018450:Disease Progression; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D011183:Postoperative Complications / Q000175:diagnosis / Q000209:etiology; D011300:Preoperative Care; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome