Quantitative sensory testing and chronic pain syndromes: a cross-sectional study from TwinsUK

Abstract

Objective: The chronic pain syndromes (CPS) include syndromes such as chronic widespread pain (CWP), dry eye disease (DED) and irritable bowel syndrome (IBS). Highly prevalent and lacking pathognomonic biomarkers, the CPS are known to cluster in individuals in part due to their genetic overlap, but patient diagnosis can be difficult. The success of quantitative sensory testing (QST) and inflammatory biomarkers as phenotyping tools in conditions such as painful neuropathies warrant their investigation in CPS. We aimed to examine whether individual QST modalities and candidate inflammatory markers were associated with CWP, DED or IBS in a large, highly phenotyped population sample.

Design: Cross-sectional study.

Setting: Community-dwelling cohort.

Participants: Twins from the TwinsUK cohort PRIMARY AND SECONDARY OUTCOME MEASURES: We compared 10 QST modalities, measured in participants with and without a CWP diagnosis between 2007 and 2012. We investigated whether inflammatory markers measured by Olink were associated with CWP, including interleukin-6 (IL-6), IL-8, IL-10, monocyte chemoattractant protein-1 and tumour necrosis factor. All analyses were repeated in DED and IBS with correction for multiple testing.

Results: In N=3022 twins (95.8% women), no association was identified between individual QST modalities and CPS diagnoses (CWP, DED and IBS). Analyses of candidate inflammatory marker levels and CPS diagnoses in n=1368 twins also failed to meet statistical significance.

Conclusion: Our findings in a large population cohort suggest a lack of true association between singular QST modalities or candidate inflammatory markers and CPS.

Keywords: Chronic Pain; Cross-Sectional Studies; Dry Eye Syndromes; EPIDEMIOLOGIC STUDIES; Irritable Bowel Syndrome.

Figure 1. Heatmap of p values from Mann-Whitney U tests comparing QST scores in participants with and without CWP, DED and IBS. Each cell represents the p value of an individual Mann-Whitney U test for the corresponding QST in the relevant CPS questionnaire population (ie, p value for Mann-Whitney U test comparing CIT scores in participants with CWP and participants without CWP=0.076). Bonferroni-corrected p value threshold=0.005. CIT, cold intolerable threshold; CPT, cold pain threshold; CWP, chronic widespread pain; DED, dry eye disease; HPST, heat pain supra threshold; HPT, heat pain threshold; IBS, irritable bowel syndrome; MDT, mechanical detection threshold; MPT, mechanical pain threshold; QST, quantitative sensory testing.