Relationship between quantitative sensory testing and pain or disability in people with spinal pain-a systematic review and meta-analysis

Sensitization of the nervous system can present as pain hypersensitivity that may contribute to clinical pain. In spinal pain, however, the relationship between sensory hypersensitivity and clinical pain remains unclear. This systematic review examined the relationship between pain sensitivity measured via quantitative sensory testing (QST) and self-reported pain or pain-related disability in people with spinal pain. Electronic databases and reference lists were searched. Correlation coefficients for the relationship between QST and pain intensity or disability were pooled using random effects models. Subgroup analyses and mixed effects meta-regression were used to assess whether the strength of the relationship was moderated by variables related to the QST method or pain condition. One hundred and forty-five effect sizes from 40 studies were included in the meta-analysis. Pooled estimates for the correlation between pain threshold and pain intensity were -0.15 (95% confidence interval [CI]: -0.18 to -0.11) and for disability -0.16 (95% CI: -0.22 to -0.10). Subgroup analyses and meta-regression did not provide evidence that these relationships were moderated by the QST testing site (primary pain/remote), pain condition (back/neck pain), pain type (acute/chronic), or type of pain induction stimulus (eg, mechanical/thermal). Fair correlations were found for the relationship between pain intensity and thermal temporal summation (0.26, 95% CI: 0.09 to 0.42) or pain tolerance (-0.30, 95% CI: -0.45 to -0.13), but only a few studies were available. Our study indicates either that pain threshold is a poor marker of central sensitization or that sensitization does not play a major role in patients' reporting of pain and disability. Future research prospects are discussed.