Purpose: The character and affect of pain in the lower back remains complex. The painDETECT questionnaire (PD-Q) serves as a screening tool aimed at differentiating pain of primarily nociceptive, neuropathic, or indeterminate origin. The purpose of this study was to assess the relationships between pain categories as described by the PD-Q and other measures of pain, disability, quality-of-life, and sociodemographic status.
Methods: A retrospective analysis of patients presenting to the Spine Service at St George Private Hospital was performed. Completed PD-Q, Oswestry Disability Index (ODI), European Quality-of-Life 5 Dimensions 3-Level Version (EQ5D3L) and Numerical Rating Scale (NRS) forms were required. An ANCOVA analysis was conducted comparing PD-Q to ODI and EQ5D3L. Subgroup analysis concerning individual ODI and EQ5D3L components was also performed.
Results: A positive association was found between PD-Q score and both ODI score (τ=0.367, p≤0.001) and NRS score (ρ=0.491, p≤0.001). Similarly, a negative association between PD-Q score and EQ5D3L score (τ=-0.340, p≤0.001) was shown. When confounded for NRS, analysis of covariance demonstrated a 37.9% higher ODI score (p≤0.001) and 30.7% lower EQ5D3L score (p≤0.001) in the neuropathic compared to nociceptive group. Individual EQ5D3L scores in the self-care (p≤0.05) and pain/discomfort (p≤0.01) categories were higher in neuropathic pain compared to nociceptive. Likewise, individual ODI scores in the personal care (p≤0.001), lifting (p≤0.001), standing (p≤0.001), sleeping (p≤0.001) and social life (p≤0.001) categories were higher in the neuropathic compared to nociceptive group. Smokers possessed higher PD-Q scores (U=1666, p≤0.05) and were 3.4 times more likely to suffer neuropathic pain (OR=3.391, 95%CI [1.407, 8.176], p≤0.01) compared to non-smokers.
Conclusion: Patients suffering primarily neuropathic pain as defined by the PD-Q experienced increased pain and disability levels in conjunction with lower quality-of-life, as demonstrated by higher NRS and ODI scores alongside lower EQ5D3L scores respectively. Smoking was associated with an increased likelihood of neuropathic pain. Various categories within both the ODI and EQ5D3L were more strongly associated with neuropathic pain. Overall, this study exemplifies the need to continue developing and improving pain assessment methodologies, noting the importance of preserving patient individuality. Such notions remain crucial in the enduring pursuit of personalised medicine.