A process of subgroup identification in non-specific low back pain using a standard clinical examination and cluster analysis.
OBJECTIVE
Non-specific low back pain (NSLBP) accounts for over 85% of all low back pain. Homogenous subgroups may exist within this diagnosis. This study derived a clinical examination and evaluated the examination's ability to identify homogenous subgroups in NSLBP.


METHODS
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.


RESULTS
Three hundred and one 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.


CONCLUSIONS
The identification of a group of hypervigilant 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.
Physiotherapy, Imperial College Healthcare, London, UK. christopher.mccarthy@nhs.net
Christopher James
CJ
McCarthy
Christopher
C
Roberts
Matthew
M
Gittins
Jacqueline Ann
JA
Oldham
D000328:Adult; D016000:Cluster Analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000145:classification* / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015588:Observer Variation; D010147:Pain Measurement; D010808:Physical Examination; D011584:Psychology; D015203:Reproducibility of Results