Real world data collection and cluster analysis in patients with sciatica due to lumbar disc herniation

The aim of this study was to identify and describe clusters of patients with similar characteristics presenting with sciatica caused by a lumbar disc herniation in secondary care.

Forty-six percent (n = 163) of the eligible patients (n = 352) completed all questionnaires and were included in a hierarchical cluster analysis. The analysis was based on baseline characteristics for pain, pain awareness and catastrophizing, disability and quality of life (QOL). Clusters were compared for the use of pain medication, employment status and allocated treatment.

Three significant clusters were identified. Cluster 2 (n = 49), coined the painfulness cluster, reported the lowest baseline characteristics for pain (>5) and disability together with a higher health-related QOL. Patients in cluster 3, labeled the painfulness and suffering cluster, had relatively high pain scores for back and leg pain (>6), high pain awareness and catastrophizing, i.e. suffering, but relatively limited disability and maintained QOL. Cluster 1 (n = 71), the painfulness-suffering and disability cluster, was characterized by the most severe back and leg pain (>7), high pain awareness and catastrophizing with the lowest QOL and highest disability. Patients in cluster 1 underwent significantly more surgery and used the most extensive pain medication (WHO III).

This research gives insight in the complex population with sciatica and is of added value to the recent, sparsely existing literature on relevant patient subgroups in the low back and leg pain population. The data suggest that VAS scores < 6 do not lead to suffering and VAS scores < 7 not to disability.