title: Predictors and outcomes of superior mesenteric artery syndrome in patients with constipation: a prospective, nested case-control study.
abstract: OBJECTIVE
  Superior mesenteric artery (SMA) syndrome may occur in patients with constipation, whereas the association between these two distinct diseases has not been confirmed yet. We investigated the incidence, risk factors and treatment strategy associated with SMA syndrome in constipated patients.
  
  
  METHODS
  We conducted a prospective nested case-control study from a 9-year hospitalization cohort (n=973). Cases were matched to controls 1:4 on factors of age and gender. Cases developed SMA syndrome in long term follow-up (n=26) and controls did not (n=104). Independent risk factors were identified by using univariate analysis and conditional logistic regression analysis. Enteral nutritional support was applied in all cases and its curative effect was evaluated by retrospective analysis.
  
  
  RESULTS
  The incidence of SMA syndrome was 2.67%. The risk factors under scrutiny were body mass index (BMI)≤18 (odds ratio (OR) 2.89, 95% CI 1.14 to 9.31) and abnormal colon transit time (OR 3.57, 95% CI 1.36 to 9.35). Twenty-two patients recovered after treatment of nutritional support, and the success rate of conservative treatment was 84.6%.
  
  
  CONCLUSIONS
  BMI≤18 and prolonged colon transit time both were risk factors associated with SMA syndrome in constipated patients. Enteral nutritional support should be adopted as the first-line treatment for this condition.
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.forename: Wen-Kui
authors.initials: WK
authors.lastname: Yu
authors.forename: Zhi-Liang
authors.initials: ZL
authors.lastname: Lin
authors.forename: Jun
authors.initials: J
authors.lastname: Jiang
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Feng
authors.forename: Ning
authors.initials: N
authors.lastname: Li
mesh_terms: D000328:Adult; D015992:Body Mass Index; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D002681:China / Q000453:epidemiology; D003106:Colon / Q000503:physiopathology; D003248:Constipation / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D004750:Enteral Nutrition; D005260:Female; D005772:Gastrointestinal Transit; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011446:Prospective Studies; D012307:Risk Factors; D013478:Superior Mesenteric Artery Syndrome / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology / Q000628:therapy; D013997:Time Factors; D016896:Treatment Outcome