title: Patient clusters in acute, work-related back pain based on patterns of disability risk factors.
abstract: OBJECTIVE
  To identify subgroups of patients with work-related back pain based on disability risk factors.
  
  
  METHODS
  Patients with work-related back pain (N = 528) completed a 16-item questionnaire of potential disability risk factors before their initial medical evaluation. Outcomes of pain, functional limitation, and work disability were assessed 1 and 3 months later.
  
  
  RESULTS
  A K-Means cluster analysis of 5 disability risk factors (pain, depressed mood, fear avoidant beliefs, work inflexibility, and poor expectations for recovery) resulted in 4 sub-groups: low risk (n = 182); emotional distress (n = 103); severe pain/fear avoidant (n = 102); and concerns about job accommodation (n = 141). Pain and disability outcomes at follow-up were superior in the low-risk group and poorest in the severe pain/fear avoidant group.
  
  
  CONCLUSIONS
  Patients with acute back pain can be discriminated into subgroups depending on whether disability is related to pain beliefs, emotional distress, or workplace concerns.
authors.affiliation: Liberty Mutual Research Institute for Safety, Center for Disability Research, Hopkinton, Massachusetts 01748, USA. william.shaw@libertymutual.com
authors.forename: William S
authors.initials: WS
authors.lastname: Shaw
authors.forename: Glenn
authors.initials: G
authors.lastname: Pransky
authors.forename: William
authors.initials: W
authors.lastname: Patterson
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Linton
authors.forename: Thomas
authors.initials: T
authors.lastname: Winters
mesh_terms: D000203:Activities of Daily Living / Q000523:psychology; D000293:Adolescent; D000328:Adult; D000368:Aged; D019567:Back Injuries / Q000150:complications* / Q000523:psychology; D001416:Back Pain / Q000453:epidemiology / Q000209:etiology* / Q000523:psychology; D016000:Cluster Analysis; D004185:Disability Evaluation; D005239:Fear; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000145:classification* / Q000453:epidemiology / Q000209:etiology; D010146:Pain; D010147:Pain Measurement / Q000379:methods / Q000523:psychology; D012307:Risk Factors; D011795:Surveys and Questionnaires