title: Downgrading of type 2 diabetes mellitus (T2DM) after obesity surgery: duration and severity matter.
abstract: BACKGROUND
  There is overwhelming evidence for the antidiabetic effect of obesity surgery, but few reports involve objective longitudinal measurements of severity of type-2 diabetes mellitus (T2DM). This study applies a grading scheme and analyses the prognostic impact of routine clinical factors.
  
  
  METHODS
  This retrospective study includes 77 obese diabetic patients with a preoperative BMI of 48.9 ± 7.8 kg/m(2) who underwent gastric banding (n = 4), Roux-en-Y gastric bypass (n = 57), or sleeve gastrectomy (n = 16) between 2007 and 2013. A 6-point scoring system graded the level of antidiabetic therapy. Downgrading was calculated from the difference between pre- and postoperative grades.
  
  
  RESULTS
  Downgrading reached its maximum at 3 months well before maximal weight loss: one grade in 6 (8 %) patients, two grades in 36 (47 %) patients, and three or more grades in 20 (26 %) patients. Age, gender, and preoperative weight had no impact on downgrading. There were no significant differences between gastric banding (median 1; 0-2), gastric bypass (median 2; 0-5), and sleeve gastrectomy (median 2; 0-4). Preoperative duration of T2DM and its severity grade were independent prognostic factors in multivariate analysis. The rate of patients who could discontinue insulin was more than 80 % when the duration of preexisting T2DM was less than 5 years as compared to 62 % when the duration was more than 5 years.
  
  
  CONCLUSIONS
  The severity of T2DM downgrades in most patients within the initial period of postoperative weight loss. Downgrading increases with shorter duration and lower severity grade of pre-existing T2DM.
authors.affiliation: St George's Hospital Medical School, University of London, Cranmer Terrace, London, SW17 0RE, UK, mkr845@gmail.com.
authors.forename: Mira
authors.initials: M
authors.lastname: Runkel
authors.forename: Silke
authors.initials: S
authors.lastname: Müller
authors.forename: Rayner
authors.initials: R
authors.lastname: Brydniak
authors.forename: Norbert
authors.initials: N
authors.lastname: Runkel
mesh_terms: D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy / Q000473:pathology* / Q000601:surgery*; D018450:Disease Progression; D005260:Female; D005743:Gastrectomy / Q000534:rehabilitation; D015390:Gastric Bypass / Q000534:rehabilitation; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000601:surgery*; D011184:Postoperative Period; D057234:Preoperative Period; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D015431:Weight Loss / Q000502:physiology
chemical_list: D007004:Hypoglycemic Agents