Psychological Factors Modulate Quantitative Sensory Testing Measures in Fibromyalgia Patients: A Systematic Review and Meta-Regression Analysis.

Objective: Considering the growing evidence that psychological variables might contribute to fibromyalgia syndrome (FMS), our study aims to understand the impact of psychological factors in quantitative sensory testing (QST) in FMS patients by performing a systematic review with meta-analysis. Methods: A systematic search was carried out in PubMed/MEDLINE, EMBASE, Web of Science, and PsycINFO databases for records up until January 2024. We included 20 studies (n = 1623, 16 randomized controlled trials, and 4 nonrandomized controlled trials) with low or moderate risk of bias included. Results: From nonrandomized evidence, our meta-analysis found a baseline relationship between anxiety, depression, and pain catastrophizing and QST measures in FMS patients. Higher pain catastrophizing levels were associated with less efficient conditioned pain modulation. Higher anxiety and depression were associated with lower pain threshold (PT). Randomized evidence showed a statistically significant increase in PT after fibromyalgia treatments (effect size = 0.29, 95% confidence interval = 0.03-0.56). The effect was not influenced by treatment type. Moreover, we found that only anxiety levels before treatment negatively influenced the PT improvements after treatment. Conclusion: FMS patients with higher anxiety levels at baseline showed a smaller increase in PT after the intervention. Depression factor was not significant in either changes in anxiety or depression. Baseline anxiety levels should be monitored as possible confounders of QST measurements. Understanding how psychological factors and QST are related in FMS patients is critical for improving the syndrome's management and treatment.