title: Applying psychological theories to evidence-based clinical practice: identifying factors predictive of lumbar spine x-ray for low back pain in UK primary care practice.
abstract: BACKGROUND
  Psychological models predict behaviour in a wide range of settings. The aim of this study was to explore the usefulness of a range of psychological models to predict the health professional behaviour 'referral for lumbar spine x-ray in patients presenting with low back pain' by UK primary care physicians.
  
  
  METHODS
  Psychological measures were collected by postal questionnaire survey from a random sample of primary care physicians in Scotland and north England. The outcome measures were clinical behaviour (referral rates for lumbar spine x-rays), behavioural simulation (lumbar spine x-ray referral decisions based upon scenarios), and behavioural intention (general intention to refer for lumbar spine x-rays in patients with low back pain). Explanatory variables were the constructs within the Theory of Planned Behaviour (TPB), Social Cognitive Theory (SCT), Common Sense Self-Regulation Model (CS-SRM), Operant Learning Theory (OLT), Implementation Intention (II), Weinstein's Stage Model termed the Precaution Adoption Process (PAP), and knowledge. For each of the outcome measures, a generalised linear model was used to examine the predictive value of each theory individually. Linear regression was used for the intention and simulation outcomes, and negative binomial regression was used for the behaviour outcome. Following this 'theory level' analysis, a 'cross-theoretical construct' analysis was conducted to investigate the combined predictive value of all individual constructs across theories.
  
  
  RESULTS
  Constructs from TPB, SCT, CS-SRM, and OLT predicted behaviour; however, the theoretical models did not fit the data well. When predicting behavioural simulation, the proportion of variance explained by individual theories was TPB 11.6%, SCT 12.1%, OLT 8.1%, and II 1.5% of the variance, and in the cross-theory analysis constructs from TPB, CS-SRM and II explained 16.5% of the variance in simulated behaviours. When predicting intention, the proportion of variance explained by individual theories was TPB 25.0%, SCT 21.5%, CS-SRM 11.3%, OLT 26.3%, PAP 2.6%, and knowledge 2.3%, and in the cross-theory analysis constructs from TPB, SCT, CS-SRM, and OLT explained 33.5% variance in intention. Together these results suggest that physicians' beliefs about consequences and beliefs about capabilities are likely determinants of lumbar spine x-ray referrals.
  
  
  CONCLUSIONS
  The study provides evidence that taking a theory-based approach enables the creation of a replicable methodology for identifying factors that predict clinical behaviour. However, a number of conceptual and methodological challenges remain.
authors.affiliation: Clinical Epidemiology Programme, Ottawa Health Research Institute and Department of Medicine, University of Ottawa, 1053 Carling Avenue, Administration Building Room 2-017, Ottawa, K1Y 4E9, Canada. jgrimshaw@ohri.ca
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Grimshaw
authors.forename: Martin P
authors.initials: MP
authors.lastname: Eccles
authors.forename: Nick
authors.initials: N
authors.lastname: Steen
authors.forename: Marie
authors.initials: M
authors.lastname: Johnston
authors.forename: Nigel B
authors.initials: NB
authors.lastname: Pitts
authors.forename: Liz
authors.initials: L
authors.lastname: Glidewell
authors.forename: Graeme
authors.initials: G
authors.lastname: Maclennan
authors.forename: Ruth
authors.initials: R
authors.lastname: Thomas
authors.forename: Debbie
authors.initials: D
authors.lastname: Bonetti
authors.forename: Anne
authors.initials: A
authors.lastname: Walker
mesh_terms: D055317:Evidence-Based Practice / Q000706:statistics & numerical data; D006801:Humans; D017116:Low Back Pain / Q000000981:diagnostic imaging*; D008960:Models, Psychological; D058007:Physicians, Primary Care / Q000523:psychology* / Q000706:statistics & numerical data; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D011859:Radiography; D012017:Referral and Consultation / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D006113:United Kingdom