title: A nationwide study of chronic pain prevalence in the general spanish population: identifying clinical subgroups through cluster analysis.
abstract: OBJECTIVE
  This study aims to assess the prevalence of chronic pain, its characteristics, and its impact on the general Spanish population. Also, to establish chronic pain patient subgroups according to the characteristics of pain and to identify variables specifically associated with each subgroup.
  
  
  METHODS
  Telephone-based, cross-sectional nationwide study.
  
  
  METHODS
  A sample of 1,957 individuals representative of the Spanish population.
  
  
  METHODS
  Data were collected through telephone interviews. A subject was considered to have chronic pain if they had suffered pain (at least 4 days a week) during the last 3 months. The subjects were divided into two subgroups through a cluster analysis, and a regression model was established to determine the variables most specifically associated with these subgroups.
  
  
  RESULTS
  The prevalence of chronic pain was 16.6% (95% confidence interval: 14.9-18.3) and among these subjects, more than 50% referred to limitations in their daily activities, 30% felt sad and/or anxious, and 47.2% indicated that their pain was affecting their family life. Two subgroups of subjects with pain were identified: 1) characterized by generalized pain in more than one location and of a long evolution (150 months); and 2) characterized by pain localized to only one site with a shorter duration (100 months). Individuals who felt anxious because of their pain and those who considered that their pain was affecting their family were more likely to belong to group 1.
  
  
  CONCLUSIONS
  Pain affects an important proportion of the Spanish adult population and that it has a strong personal impact. Two pain groups were clearly distinguished by their clinical characteristics.
authors.affiliation: Preventive Medicine and Public Health Area, Facultad de Enfermería y Fisioterapia, University of Cádiz, Cádiz, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Dueñas
authors.forename: Alejandro
authors.initials: A
authors.lastname: Salazar
authors.forename: Begoña
authors.initials: B
authors.lastname: Ojeda
authors.forename: Fernando
authors.initials: F
authors.lastname: Fernández-Palacín
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Micó
authors.forename: Luis Miguel
authors.initials: LM
authors.lastname: Torres
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Failde
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D059350:Chronic Pain / Q000453:epidemiology* / Q000523:psychology; D016000:Cluster Analysis; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D013030:Spain / Q000453:epidemiology; D055815:Young Adult
keywords: Chronic Pain; Clusters; Cross-Sectional Study; General Population; Prevalence