title: Meta-analysis: The value of clinical assessment in the diagnosis of deep venous thrombosis.
abstract: BACKGROUND
  Clinical assessment of suspected deep venous thrombosis (DVT) should be based on systematically evaluated evidence.
  
  
  OBJECTIVE
  To determine whether clinical findings, risk scores, and physicians' empirical judgments affect the likelihood of detecting DVT on definitive testing.
  
  
  METHODS
  MEDLINE, EMBASE, CINAHL, Web of Science, Cochrane Database of Systematic Reviews, Cochrane Controlled Trials Register, Database of Reviews of Effectiveness, ACP Journal Club, and citation lists (1966 to January 2005).
  
  
  METHODS
  Cohort studies published in English, French, Spanish, or Italian that compared clinical assessment with a reference standard.
  
  
  METHODS
  The authors extracted standardized data, including setting, exclusions, population characteristics, reference standard, and results, and assessed quality against validated criteria.
  
  
  RESULTS
  The authors combined data by using random-effects meta-analysis and, if appropriate, used meta-regression to identify covariates that predicted diagnostic accuracy. Only malignancy (likelihood ratio [LR], 2.71), previous DVT (LR, 2.25), recent immobilization (LR, 1.98), difference in calf diameter (LR, 1.80), and recent surgery (LR, 1.76) were useful for ruling in DVT, while only absence of calf swelling (LR, 0.67) or difference in calf diameter (LR, 0.57) was useful for ruling out DVT. The Wells clinical score was more valuable than the individual characteristics; it stratified patients into groups with high (LR, 5.2), intermediate, and low (LR, 0.25) probability of DVT. The Wells score seemed able to stratify patients by risk only for proximal DVT, and it performed better in cohorts that were younger or excluded patients with previous thromboembolism.
  
  
  CONCLUSIONS
  Pooled estimates were subject to substantial heterogeneity. This may limit extrapolation between observers and settings. Only published studies were included, so findings may be subject to publication bias.
  
  
  CONCLUSIONS
  Individual clinical features are of limited value in diagnosing DVT. Overall assessment of clinical probability by using the Wells score is more useful.
authors: University of Sheffield, Sheffield, United Kingdom. s.goodacre@sheffield.ac.uk
authors: Steve
authors: S
authors: Goodacre
authors: Alex J
authors: AJ
authors: Sutton
authors: Fiona C
authors: FC
authors: Sampson
mesh_terms: D006801:Humans; D016013:Likelihood Functions; D011237:Predictive Value of Tests; D012372:ROC Curve; D012307:Risk Factors; D020246:Venous Thrombosis / Q000175:diagnosis*