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Novel approach to characterising individuals with low back-related leg pain

cluster identification with latent class analysis and 12-month follow-up

Stynes, Siobhán*; Konstantinou, Kika; Ogollah, Reuben; Hay, Elaine M.; Dunn, Kate M.

doi: 10.1097/j.pain.0000000000001147
Research Paper

Traditionally, low back-related leg pain (LBLP) is diagnosed clinically as referred leg pain or sciatica (nerve root involvement). However, within the spectrum of LBLP, we hypothesised that there may be other unrecognised patient subgroups. This study aimed to identify clusters of patients with LBLP using latent class analysis and describe their clinical course. The study population was 609 LBLP primary care consulters. Variables from clinical assessment were included in the latent class analysis. Characteristics of the statistically identified clusters were compared, and their clinical course over 1 year was described. A 5 cluster solution was optimal. Cluster 1 (n = 104) had mild leg pain severity and was considered to represent a referred leg pain group with no clinical signs, suggesting nerve root involvement (sciatica). Cluster 2 (n = 122), cluster 3 (n = 188), and cluster 4 (n = 69) had mild, moderate, and severe pain and disability, respectively, and response to clinical assessment items suggested categories of mild, moderate, and severe sciatica. Cluster 5 (n = 126) had high pain and disability, longer pain duration, and more comorbidities and was difficult to map to a clinical diagnosis. Most improvement for pain and disability was seen in the first 4 months for all clusters. At 12 months, the proportion of patients reporting recovery ranged from 27% for cluster 5 to 45% for cluster 2 (mild sciatica). This is the first study that empirically shows the variability in profile and clinical course of patients with LBLP including sciatica. More homogenous groups were identified, which could be considered in future clinical and research settings.

Distinct novel clusters of primary care patients with back-related leg pain including sciatica were identified and compared using baseline characteristics and 12-month follow-up data.

Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, United Kingdom

Corresponding author. Address: Arthritis Research UK Primary Care Centre, Research Institute for Primary Care and Health Sciences, Keele University, Keele, Staffordshire, ST5 5BG, United Kingdom. Tel.: 0044 1782 733925; fax: 0044 1782 734719. E-mail address: (S. Stynes).

Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.

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Received July 28, 2017

Received in revised form October 27, 2017

Accepted December 22, 2017

© 2018 International Association for the Study of Pain
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