Pain Sensitivity Subgroups in Individuals With Spine Pain: Potential Relevance to Short-Term Clinical Outcome.

Cluster analysis can be employed to identify individuals similar in profile based on response to multiple pain sensitivity measures. There are limited investigations into how empirically-derived pain sensitivity subgroups affect clinical outcomes for individuals with spine pain. The goal of this study was to examine empirically-derived subgroups based on pressure and thermal pain sensitivity in persons with spine pain and to examine subgroup influence on 2-week clinical pain intensity and disability outcomes. Baseline and 2-week outcome data from 157 participants with low back (n = 110) and neck (n = 47) pain were examined. Participants completed demographic, psychological, and clinical information and were assessed using pain sensitivity protocols including pressure (suprathreshold pressure pain) and thermal pain sensitivity (thermal heat threshold and tolerance, suprathreshold heat pain, temporal summation). A hierarchical agglomerative cluster analysis was used to create subgroups based on pain sensitivity responses. Variations in baseline variables, clinical pain intensity, and disability were examined.ResultsThree pain sensitivity subgroups were derived: “Low Pain Sensitivity”, “High Thermal Static Sensitivity”, “High Pressure and Thermal Dynamic Sensitivity”. There were variations in proportion of individuals meeting a 30% change in pain intensity (p < 0.05), where fewer individuals within the High Pressure and Thermal Dynamic Sensitivity group (Adjusted OR = 0.3 [95% CI: 0.1; 0.8]) achieved successful outcome.LimitationsOnly 2-week outcomes are reported.

The study identified distinct pain sensitivity subgroups for individuals with spine pain: "Low Pain Sensitivity", "High Thermal Static Sensitivity", "High Pressure and Thermal Dynamic Sensitivity", with the latter group showing worse clinical outcome for pain intensity. Future studies ought to try to confirm these findings.