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Analysis of quantitative sudomotor axon reflex test patterns in patients with complex regional pain syndrome diagnosed using the Budapest criteria
  1. Ho-Jin Lee1,
  2. Se Eun Kim1,
  3. Jee Youn Moon1,2,
  4. Je-Young Shin3 and
  5. Yong-Chul Kim1,2
  1. 1Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Jongno-gu, Korea (the Republic of)
  2. 2Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Jongno-gu, Korea (the Republic of)
  3. 3Department of Neurology, Seoul National University Hospital, Jongno-gu, Korea (the Republic of)
  1. Correspondence to Dr Jee Youn Moon, Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Jongno-gu, Seoul, Korea (the Republic of); jymoon0901{at}


Background Although the quantitative sensory axon reflex test (QSART) is used to evaluate sudomotor dysfunction in the diagnosis of complex regional pain syndrome (CRPS), its validity remains controversial. This study investigated the diagnostic performance of the QSART for CRPS and assessed associations between results of the QSART and other clinical variables.

Methods We examined the electronic medical records of 196 consecutive patients who underwent the QSART with a suspected diagnosis of CRPS, during the period from January 2013 to December 2015. To assess the diagnostic performance of the QSART for CRPS based on the Budapest research criteria, we calculated sensitivity, specificity, positive likelihood ratio and negative likelihood ratio. Furthermore, we performed binary logistic regression analyses to investigate the relationships between QSART results and other clinical variables.

Results The sensitivity and specificity of the QSART for diagnosing CRPS were 67.6% and 40.6%, respectively. The OR for diagnosing CRPS using the QSART was not statistically significant (1.43; 95% CI 0.65 to 3.14; p=0.376), whereas it was for distinguishing CRPS types I and II (4.11; 95% CI 1.34 to 12.57; p=0.013). In multivariable analysis, there were no correlations between the results of the QSART and other variables, except hypertension (OR=0.34; 95% CI 0.13 to 0.91; p=0.032).

Conclusion The QSART showed low diagnostic value as a screening or a confirmatory test for CRPS according to the Budapest research criteria. CRPS type II was more likely than CRPS type I to result in abnormal QSART results.

  • chronic pain: complex regional pain syndrome
  • chronic pain: diagnostic pain procedures
  • chronic pain: sympathetic blocks
  • chronic pain: neuropathic pain

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  • Presented at Interim data from this work were presented at the 67th Korean Pain Society Scientific Meeting and Training Course, Nov 17, 2018.

  • Contributors HL: data collection/analysis, drafting and revision of the article. SEK: data collection/analysis. JYM: concept/design, approval of the article, drafting and critical review of the article. J-YS: data collection/analysis. Y-CK: concept/design, approval of the article and revision of the article.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data are available on reasonable request.