title: Usefulness of bone scintigraphy for the diagnosis of Complex Regional Pain Syndrome 1: A systematic review and Bayesian meta-analysis.
abstract: BACKGROUND
  Since 2007, the Budapest criteria are recommended for the diagnosis of Complex Regional Pain Syndrome (CRPS) 1. The usefulness of bone scintigraphy (BS, index test) for the diagnosis of CRPS 1 remains controversial. Imperfect reference tests (RT) result in underestimation of the diagnostic accuracy of BS. Further, biased results can occur when a dependency between the RT and BS exists. The objective was to assess the impact of different RTs, specifically the Budapest criteria, and the assumed imperfect nature of the RT on the diagnostic accuracy of BS. Further, we analyzed the association between baseline characteristics and positive BS in patients with CRPS 1.
  
  
  METHODS
  Systematic literature review and Bayesian meta-analysis to assess the test accuracy of BS with and without accounting for the imperfect nature of the RT. We examined correlations (Spearman correlation coefficients / Wilcoxon tests) between baseline characteristics and the proportion of positive BS in patients with CRPS 1.
  
  
  RESULTS
  The pooled sensitivity was 0.804 (95% credible interval (CI) 0.225-1.0, 21 studies) and specificity 0.853 (95%CI 0.278-1.00). Sensitivity and specificity of BS increased when accounting for the imperfect nature of the RT. However, in studies using Budapest criteria as reference, the sensitivity decreased (0.551; 95% CI 0.046-1) and the specificity increased (0.935; 95% CI 0.306-1). Shorter disease duration and a higher proportion of males were associated with a higher proportion of positive BS (27 studies, disease duration <52 weeks Wilcoxon test p = 0.047, female proportion Spearman correlation -0.63, p = 0.009).
  
  
  CONCLUSIONS
  Compared to the accepted Budapest diagnostic criteria BS cannot be used to rule-in the diagnosis of CRPS 1. In patients with negative BS CRPS 1 is less likely the underlying illness. Studies using older or no diagnostic criteria should not be used to evaluate the diagnostic accuracy of BS in CRPS 1.
authors.affiliation: Horten Centre for Patient Oriented Research and Knowledge Transfer, University of Zurich, Pestalozzistrasse 24, Zurich, Switzerland.|Division of General Internal Medicine, Bern University Hospital, Bern University, Freiburgstrasse 8, Bern, Switzerland.
authors.forename: Maria M
authors.identifier: http://orcid.org/0000-0001-6347-0198
authors.initials: MM
authors.lastname: Wertli
authors.affiliation: Department of Physical Medicine and Rheumatology, Balgrist University Hospital, Forchstrasse 340, Zurich, Switzerland.
authors.forename: Florian
authors.initials: F
authors.lastname: Brunner
authors.affiliation: Horten Centre for Patient Oriented Research and Knowledge Transfer, University of Zurich, Pestalozzistrasse 24, Zurich, Switzerland.
authors.forename: Johann
authors.initials: J
authors.lastname: Steurer
authors.affiliation: Horten Centre for Patient Oriented Research and Knowledge Transfer, University of Zurich, Pestalozzistrasse 24, Zurich, Switzerland.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Held
mesh_terms: D001842:Bone and Bones / Q000000981:diagnostic imaging*; D020918:Complex Regional Pain Syndromes / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D011877:Radionuclide Imaging / Q000379:methods*