Content » Vol 45, Issue 2

Original report

Sub-grouping patients with non-specific low back pain based on cluster analysis of discriminatory clinical items

Evdokia Billis, Christopher J. McCarthy, Chris Roberts, John Gliatis, Maria Papandreou, George Gioftsos, Jacqueline A. Oldham
Department of Physiotherapy, Branch Department of Aigion, Technological Educational Institute (T.E.I.) of Aigion, Psaron 6, Aigion, 25100, Greece. E-mail:
DOI: 10.2340/16501977-1100


Objective: To identify potential subgroups amongst patients with non-specific low back pain based on a consensus list of potentially discriminatory examination items.
Design: Exploratory study.
Participants: A convenience sample of 106 patients with non-specific low back pain (43 males, 63 females, mean age 36 years, standard deviation 15.9 years) and 7 physiotherapists.
Methods: Based on 3 focus groups and a two-round Delphi involving 23 health professionals and a random stratified sample of 150 physiotherapists, respectively, a comprehensive examination list comprising the most “discriminatory” items was compiled. Following reliability analysis, the most reliable clinical items were assessed with a sample of patients with non-specific low back pain. K-means cluster analysis was conducted for 2-, 3- and 4-cluster options to explore for meaningful homogenous subgroups.
Results: The most clinically meaningful cluster was a two-subgroup option, comprising a small group (n = 24) with more severe clinical presentation (i.e. more widespread pain, functional and sleeping problems, other symptoms, increased investigations undertaken, more severe clinical signs, etc.) and a larger less dysfunctional group (n = 80).
Conclusion: A number of potentially discriminatory clinical items were identified by health professionals and sub-classified, based on a sample of patients with non-specific low back pain, into two subgroups. However, further work is needed to validate this classification process.

Lay Abstract


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