Quantitative sensory testing not reliable as a means for characterizing chronic pain syndromes

1. Chronic pain syndromes including fibromyalgia, dry eye disease, and irritable bowel syndrome showed no significant association with quantitative sensory testing modalities or inflammatory markers

Evidence Rating Level: 3 (Average)

Chronic pain is a widespread and highly heterogenous group if diseases that requires a method of pain phenotyping and measurement. Chronic pain syndromes (CPS) are a cluster of conditions including fibromyalgia, dry eye disease (DED), and irritable bowel syndrome (IBS). CPS show genetic and symptomology overlap in the TwinsUK cohort. Quantitative sensory testing (QST) is composed of psychophysical tests that assess perceptions caused by various sensory stimuli including thermal and mechanical stimuli at various intensities. QST has been validated in grading neuropathic pain but has not been readily adopted for chronic pain groups. Another strategy to quantify pain is the use of inflammatory markers. This cross-sectional study aimed to determine if QST and inflammatory markers can be used as phenotyping tools for CPS. 10 QST modalities were administered, and scores were compared between participants with fibromyalgia and those without. Similarly, DED and IBS patients were compared to controls. No significant differences were seen between patients with fibromyalgia, DED, or IBS compared to controls in any of the 10 QST modalities. Inflammatory markers investigated were determined a priori and included interleukin-6 (IL-6), IL-8, IL-10, monocyte chemoattractant protein-1 (MCP-1) and tumour necrosis factor (TNF). After correction for age, BMI, and twin relatedness, no significant associations were found between fibromyalgia, DED, or IBS. In a mixed effects logistic regression, IBS was associated with IL-8 (p=0.036). As the first large-scale investigation into QST modalities in CPS, no true associations were seen. Additionally, the examined inflammatory markers were also candidate inflammatory markers for CPS.

Click to read the study in BMJ Open

Image: PD

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