title: Impact of bariatric surgery on clinical depression. Interrupted time series study with matched controls.
abstract: BACKGROUND
  Obesity is associated with depression. This study aimed to evaluate whether clinical depression is reduced after bariatric surgery (BS).
  
  
  METHODS
  Obese adults who received BS procedures from 2002 to 2014 were sampled from the UK Clinical Practice Research Datalink. An interrupted time series design, with matched controls, was conducted from three years before, to a maximum of seven years after surgery. Controls were matched for body mass index (BMI), age, gender and year of procedure. Clinical depression was defined as a medical diagnosis recorded in year, or an antidepressant prescribed in year to a participant ever diagnosed with depression. Adjusted odds ratios (AOR) were estimated.
  
  
  RESULTS
  There were 3045 participants (mean age 45.9; mean BMI 44.0kg/m(2)) who received BS, including laparoscopic gastric banding in 1297 (43%), gastric bypass in 1265 (42%), sleeve gastrectomy in 477 (16%) and six undefined. Before surgery, 36% of BS participants, and 21% of controls, had clinical depression; between-group AOR, 2.02, 95%CI 1.75-2.33, P<0.001. In the second post-operative year 32% had depression; AOR, compared to time without surgery, 0.83 (0.76-0.90, P<0.001). By the seventh year, the prevalence of depression increased to 37%; AOR 0.99 (0.76-1.29, P=0.959).
  
  
  CONCLUSIONS
  Despite matching there were differences in depression between BS and control patients, representing the highly selective nature of BS.
  
  
  CONCLUSIONS
  Depression is frequent among individuals selected to undergo bariatric surgery. Bariatric surgery may be associated with a modest reduction in clinical depression over the initial post-operative years but this is not maintained.
authors.affiliation: King׳s College London, Department of Primary Care and Public Health Sciences, Capital House, 42 Weston Street, London SE1 3QD, UK; NIHR Biomedical Research Centre at Guy׳s and St Thomas' NHS Foundation Trust, Great Maze Pond, London SE1 9RT, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Booth
authors.affiliation: Department of Surgery, Whittington Hospital, Magdala Avenue, London N19 5NF, UK.
authors.forename: Omar
authors.initials: O
authors.lastname: Khan
authors.affiliation: King׳s College London, Department of Primary Care and Public Health Sciences, Capital House, 42 Weston Street, London SE1 3QD, UK; NIHR Biomedical Research Centre at Guy׳s and St Thomas' NHS Foundation Trust, Great Maze Pond, London SE1 9RT, UK.
authors.forename: A Toby
authors.initials: AT
authors.lastname: Prevost
authors.affiliation: Department of Surgery, St George׳s Hospital, Blackshaw Road, London SW17 0QT, UK.
authors.forename: Marcus
authors.initials: M
authors.lastname: Reddy
authors.affiliation: King׳s College London, Department of Primary Care and Public Health Sciences, Capital House, 42 Weston Street, London SE1 3QD, UK; NIHR Biomedical Research Centre at Guy׳s and St Thomas' NHS Foundation Trust, Great Maze Pond, London SE1 9RT, UK.
authors.forename: Judith
authors.initials: J
authors.lastname: Charlton
authors.affiliation: King׳s College London, Department of Primary Care and Public Health Sciences, Capital House, 42 Weston Street, London SE1 3QD, UK; NIHR Biomedical Research Centre at Guy׳s and St Thomas' NHS Foundation Trust, Great Maze Pond, London SE1 9RT, UK. Electronic address: martin.gulliford@kcl.ac.uk.
authors.forename: Martin C
authors.initials: MC
authors.lastname: Gulliford
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000379:methods; D015992:Body Mass Index; D003863:Depression; D003865:Major Depressive Disorder; D005260:Female; D015390:Gastric Bypass; D015391:Gastroplasty; D006801:Humans; D065186:Interrupted Time Series Analysis; D010535:Laparoscopy; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D009767:Obesity, Morbid / Q000523:psychology* / Q000601:surgery*; D011184:Postoperative Period; D013997:Time Factors; D016896:Treatment Outcome
keywords: Antidepressant prescribing; Bariatric surgery; Comorbidity; Depression; Obesity; Primary care