title: Time Since Inciting Event Is Associated With Higher Centralized Pain Symptoms in Patients Diagnosed With Complex Regional Pain Syndrome.
abstract: OBJECTIVE
  We hypothesized that patients with complex regional pain syndrome (CRPS) with a longer time since their inciting event would demonstrate more symptoms of centralized pain.
  
  
  METHODS
  We conducted a cross-sectional analysis of 160 patients with CRPS using validated measures of pain, negative mood, and functioning at the time of their new patient evaluation. The 2011 Fibromyalgia Survey Criteria is a validated self-report measure of widespread body pain and comorbid symptoms (eg, trouble thinking, headaches). The measure was used as a surrogate for centralized pain symptoms. Univariate analyses and multivariate linear regression models were used to assess the associations between patient characteristics and the duration of CRPS.
  
  
  RESULTS
  The cohort was divided into tertiles based on the time since the inciting event (<12 months; 1-3 years; >3 years) for univariate comparisons. Unlike the other measures of pain, mood, and function, the fibromyalgia survey score was significantly associated with a longer duration of symptoms. In a multivariate model adjusting for age and sex, each year since the inciting event was associated with an increase of 0.28 in fibromyalgia survey score (Est 0.28; 95% confidence interval, 0.11-0.46; P = 0.002). The finding was distinct from self-reported spread of CRPS symptoms, which was not different based on time since the inciting event.
  
  
  CONCLUSIONS
  Our findings suggest that the longer the patients have CRPS the more likely they are to report symptoms suggestive of centralized pain. These data may explain why some patients with a longer duration of CRPS do not respond to peripherally directed therapies.
authors.affiliation: From the Division of Pain Medicine and the Back and Pain Center, Department of Anesthesiology, University of Michigan, Ann Arbor, MI.
authors.forename: Goodarz
authors.initials: G
authors.lastname: Golmirzaie
authors.forename: Lindsay S
authors.initials: LS
authors.lastname: Holland
authors.forename: Stephanie E
authors.initials: SE
authors.lastname: Moser
authors.forename: Mohit
authors.initials: M
authors.lastname: Rastogi
authors.forename: Afton L
authors.initials: AL
authors.lastname: Hassett
authors.forename: Chad M
authors.initials: CM
authors.lastname: Brummett
mesh_terms: D015897:Comorbidity; D020918:Complex Regional Pain Syndromes / Q000209:etiology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005356:Fibromyalgia; D006801:Humans; D010146:Pain / Q000209:etiology*; D013997:Time Factors