title: A comparison of observational studies and controlled trials of heparin in ulcerative colitis.
abstract: OBJECTIVE
  To compare the efficacy of heparin in ulcerative colitis (UC) as demonstrated in observational studies and controlled clinical trials.
  
  
  BACKGROUND
  Ulcerative colitis (UC) is a chronic condition with a relapsing and remitting course. Several studies have been conducted (observational and controlled clinical trials) to test the usefulness of heparin in this condition but the results of these studies are variable. Some studies demonstrate efficacy while others do not.
  
  
  METHODS
  We pooled the results of observational studies and clinical trials separately in order to compare the results of observational studies and clinical trials using meta-analysis. With the aid of Medline and a manual search in Index Medicus and cross-references of articles published up to July 2003, we identified studies designed to evaluate the effects of heparin on UC. The pooled cure rate in observational studies was calculated.
  
  
  RESULTS
  The results of controlled clinical trials evaluated using meta-analysis showed that the pooled cure rate for observational studies was 87.7% (range 80 - 100). The odds ratio for the controlled trial was 0.34 (95% CI 0.08 - 1.49) using a random effects model and 0.21 (95% CI 0.06 - 1.38) using a fixed effects model. The results of meta-analysis demonstrate a non-significant effect of heparin in controlled clinical trials.
  
  
  CONCLUSIONS
  The findings of the clinical trials differ markedly from observational studies and indicate a lack of efficacy of heparin in patients with ulcerative colitis.
authors.affiliation: Department of Pharmacology, Postgraduate Institute of Medical Education & Research, Chandigarh, India.
authors.forename: S
authors.initials: S
authors.lastname: Malhotra
authors.forename: A
authors.initials: A
authors.lastname: Kondal
authors.forename: N
authors.initials: N
authors.lastname: Shafiq
authors.forename: S
authors.initials: S
authors.lastname: Sidhu
authors.forename: D K
authors.initials: DK
authors.lastname: Bhasin
authors.forename: P
authors.initials: P
authors.lastname: Pandhi
mesh_terms: D003093:Colitis, Ulcerative / Q000188:drug therapy*; D005343:Fibrinolytic Agents / Q000627:therapeutic use*; D006493:Heparin / Q000627:therapeutic use*; D006801:Humans; D016017:Odds Ratio; D016032:Randomized Controlled Trials as Topic
chemical_list: D005343:Fibrinolytic Agents; D006493:Heparin