title: Real-life assessment of the validity of patient global impression of change in fibromyalgia.
abstract: OBJECTIVE
  Patient Global Rating of Change (GRC) scales are commonly used in routine clinical care given their ease of use, availability and short completion time. This analysis aimed at assessing the validity of Patient Global Impression of Change (PGIC), a GRC scale commonly used in fibromyalgia, in a Canadian real-life setting.
  
  
  METHODS
  167 fibromyalgia patients with available PGIC data were recruited in 2005-2013 from a Canadian tertiary-care multidisciplinary clinic. In addition to PGIC, disease severity was assessed with: pain visual analogue scale (VAS); Patient Global Assessment (PGA); Fibromyalgia Impact Questionnaire (FIQ); Health Assessment Questionnaire (HAQ); McGill Pain Questionnaire; body map. Multivariate linear regression assessed the PGIC relationship with disease parameter improvement while adjusting for follow-up duration and baseline parameter levels. The Spearman's rank coefficient assessed parameter correlation.
  
  
  RESULTS
  Higher PGIC scores were significantly (p<0.001) associated with greater improvement in pain, PGA, FIQ, HAQ and the body map. A statistically significant moderate positive correlation was observed between PGIC and FIQ improvement (r=0.423; p<0.001); correlation with all remaining disease severity measures was weak. Regression analysis confirmed a significant (p<0.001) positive association between improvement in all disease severity measures and PGIC. Baseline disease severity and follow-up duration were identified as significant independent predictors of PGIC rating.
  
  
  CONCLUSIONS
  Despite that only a weak correlation was identified between PGIC and standard fibromyalgia outcomes improvement, in the absence of objective outcomes, PGIC remains a clinically relevant tool to assess perceived impact of disease management. However, our analysis suggests that outcome measures data should not be considered in isolation but, within the global clinical context.
authors.affiliation: JSS Medical Research , St-Laurent, Quebec , Canada.
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Rampakakis
authors.affiliation: Alan Edwards Pain Management Unit , McGill University Health Centre , Montreal, Quebec , Canada.
authors.forename: Peter A
authors.initials: PA
authors.lastname: Ste-Marie
authors.affiliation: JSS Medical Research , St-Laurent, Quebec , Canada ; Department of Surgical Research , Jewish General Hospital , Montreal, Quebec , Canada.
authors.forename: John S
authors.initials: JS
authors.lastname: Sampalis
authors.affiliation: JSS Medical Research , St-Laurent, Quebec , Canada ; Department of Surgery , McGill University , Montreal, Quebec , Canada.
authors.forename: Angeliki
authors.initials: A
authors.lastname: Karellis
authors.affiliation: Alan Edwards Pain Management Unit , McGill University Health Centre , Montreal, Quebec , Canada.
authors.forename: Yoram
authors.initials: Y
authors.lastname: Shir
authors.affiliation: Alan Edwards Pain Management Unit , McGill University Health Centre , Montreal, Quebec , Canada ; Department of Rheumatology , McGill University Health Centre , Montreal, Quebec , Canada.
authors.forename: Mary-Ann
authors.initials: MA
authors.lastname: Fitzcharles
keywords: Disease Activity; Fibromyalgis/Pain Syndromes; Patient perspective