RISK PROFILING IN CHRONIC LOW BACK PAIN: NEUROPHYSIOLOGICAL AND NEUROMUSCULAR DIFFERENCES ACROSS LEVELS OF RISK OF POOR PAIN PROGNOSIS—A CROSS-SECTIONAL STUDY

this study aimed to compare neurophysiological and neuromuscular outcomes across different risk strata of poor prognosis for pain in participants with CLBP. The study hypothesis predicted that psychosocial factors, implicit in the risk of poor pain prognosis, would exert a progressively negative effect on neurophysiological and neuromuscular outcomes in participants with CLBP.
Participants with CLBP were classified into low-, intermediate-, and high-risk groups based on risk strata for poor pain prognosis. Neurophysiological outcomes were assessed using heart rate variability (HRV) recorded with a qualified heart rate monitor. The rate of force development (at 100 and 200 milliseconds), maximal isometric strength, and proprioceptive accuracy were assessed using a portable traction dynamometer as neuromuscular outcomes. We performed inferential statistical analyses alongside the respective effect sizes (metrics expressing clinical magnitude).
Statistical analyses were performed using the free software Jamovi (version 2.4.11). An alpha level of 0.05 was used. Given the study’s cross-sectional design, comparisons related to sample characterization variables were conducted using generalized linear models (GzLM). These models are based on maximum likelihood estimation and use the wald χ-square test (Wald χ²) to assess the effect of variables within the model. The risk strata for poor pain prognosis (LR, MR, and HR) were included as a factor in the analyses. Effect size (ES) estimates were included in the inferential analyses using Hedges’ g. The effect sizes were interpreted according to the following thresholds: null (<0.10), very small (0.10–0.19), moderate (0.20–0.79), large (0.80–1.19), very large (1.20–1.99), and huge (>2.0). Higher ES values indicate greater clinical relevance, reflecting larger differences between the means of each comparison pair .