title: Variations in GPs' decisions to investigate suspected lung cancer: a factorial experiment using multimedia vignettes.
abstract: BACKGROUND
  Lung cancer survival is low and comparatively poor in the UK. Patients with symptoms suggestive of lung cancer commonly consult primary care, but it is unclear how general practitioners (GPs) distinguish which patients require further investigation. This study examined how patients' clinical and sociodemographic characteristics influence GPs' decisions to initiate lung cancer investigations.
  
  
  METHODS
  A factorial experiment was conducted among a national sample of 227 English GPs using vignettes presented as simulated consultations. A multimedia-interactive website simulated key features of consultations using actors ('patients'). GP participants made management decisions online for six 'patients', whose sociodemographic characteristics systematically varied across three levels of cancer risk. In low-risk vignettes, investigation (ie, chest X-ray ordered, computerised tomography scan or respiratory consultant referral) was not indicated; in medium-risk vignettes, investigation could be appropriate; in high-risk vignettes, investigation was definitely indicated. Each 'patient' had two lung cancer-related symptoms: one volunteered and another elicited if GPs asked. Variations in investigation likelihood were examined using multilevel logistic regression.
  
  
  RESULTS
  GPs decided to investigate lung cancer in 74% (1000/1348) of vignettes. Investigation likelihood did not increase with cancer risk. Investigations were more likely when GPs requested information on symptoms that 'patients' had but did not volunteer (adjusted OR (AOR)=3.18; 95% CI 2.27 to 4.70). However, GPs omitted to seek this information in 42% (570/1348) of cases. GPs were less likely to investigate older than younger 'patients' (AOR=0.52; 95% CI 0.39 to 0.7) and black 'patients' than white (AOR=0.68; 95% CI 0.48 to 0.95).
  
  
  CONCLUSIONS
  GPs were not more likely to investigate 'patients' with high-risk than low-risk cancer symptoms. Furthermore, they did not investigate everyone with the same symptoms equally. Insufficient data gathering could be responsible for missed opportunities in diagnosis.
authors.affiliation: Department of Applied Health Research, UCL, London, UK.
authors.forename: Jessica
authors.identifier: http://orcid.org/0000-0003-3468-129X
authors.initials: J
authors.lastname: Sheringham
authors.affiliation: Department of Applied Health Research, UCL, London, UK.
authors.forename: Rachel
authors.initials: R
authors.lastname: Sequeira
authors.affiliation: Queen Mary University of London, Centre for Cancer Prevention, London, UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Myles
authors.affiliation: University of Exeter, Peninsula College of Medicine and Dentistry, Exeter, UK.
authors.forename: William
authors.initials: W
authors.lastname: Hamilton
authors.affiliation: Department of Public Health, London Borough of Waltham Forest, London, UK.
authors.forename: Joe
authors.initials: J
authors.lastname: McDonnell
authors.affiliation: Queen Mary University of London, Centre for Cancer Prevention, London, UK.
authors.forename: Judith
authors.initials: J
authors.lastname: Offman
authors.affiliation: Queen Mary University of London, Centre for Cancer Prevention, London, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Duffy
authors.affiliation: Department of Applied Health Research, UCL, London, UK.
authors.forename: Rosalind
authors.initials: R
authors.lastname: Raine
mesh_terms: D000066491:Clinical Decision-Making / Q000379:methods*; D019937:Diagnostic Techniques and Procedures; D058005:General Practitioners / Q000523:psychology*; D006801:Humans; D020407:Internet; D008175:Lung Neoplasms / Q000175:diagnosis*; D019212:Multimedia; D016544:Patient Simulation; D010818:Practice Patterns, Physicians'; D012307:Risk Factors; D012737:Sex Factors; D012959:Socioeconomic Factors; D006113:United Kingdom
keywords: Diagnostic errors; General practice; Health services research; Primary care; Simulation