A process of subgroup identification in non-specific low back pain using a standard clinical examination and cluster analysis

Physiotherapy Research International, 05/07/2012

The identification of a group of hypervigilant non–specific low back pain (NSLBP) patients should allow the interventions to be targeted towards this group. A valid, standardized clinical examination does contribute to the diagnostic management of NSLBP.


  • Patients with NSLBP were examined using a standardized clinical examination.
  • Each patient was examined by two physiotherapists.
  • Data were analysed for item reliability and the presence of distinct subgroups using cluster analysis.
  • Cross–validation of the clusters identified was conducted.


  • 301 patients were examined.
  • The inter–tester reliability of the majority of items was moderate to substantial (52% of items with kappa>0.40).
  • A K–means cluster analysis of the two data sets revealed agreement on the presence of two subgroups.
  • One group (n=47, 16%) had higher fear avoidance beliefs, anxiety and disability.
  • They were more likely to be provoked by pain provocative tests.
  • They were also more likely to be judged as having central sensitization and a dominant psychosocial component to their presentation.

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