title: The International Classification of Functioning, Disability and Health: a systematic review of observational studies.
abstract: OBJECTIVE
  To systematically review the use of the International Classification of Functioning, Disability and Health (ICF) in observational studies.
  
  
  METHODS
  This study is a systematic review of articles that use the ICF in observational studies. We took into account the observational design papers available in databases such as PubMed, Lilacs and SciELO, published in English and Portuguese from January 2001 to June 2011. We excluded those in which the samples did not comprise individuals, those about children and adolescents, and qualitative methodology articles. After reading the abstracts of 265 identified articles, 65 met the inclusion criteria. Of these, 18 were excluded. The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) adapted Checklist, with 15 items needed for observational studies, was applied to the 47 remaining articles. Any paper that met 12 of these criteria was included in this systematic review.
  
  
  RESULTS
  29 articles were reviewed. Regarding the ICF application methodology, the checklist was used in 31% of the articles, the core set in 31% and the ICF categories in 31%. In the remaining 7%, it was not possible to define the applied methodology. In most papers (41%), qualifiers were used in their original format. As far as the area of knowledge is concerned, most of the studies were related to Rheumatology (24%) and Orthopedics (21%). Regarding the study design, 83% of the articles used cross-sectional studies.
  
  
  CONCLUSIONS
  Results indicate a wide scientific production related to ICF over the past 10 years. Different areas of knowledge are involved in the debate on the improvement of information on morbidity. However, there are only a few quantitative epidemiological studies involving the use of ICF. Future studies are needed to improve data related to functioning and disability.
authors.affiliation: Institute for Studies in Public Health, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Luciana
authors.initials: L
authors.lastname: Castaneda
authors.affiliation: Augusto Motta University Center, Instituto Nacional de Câncer, University Center, Rio de Janeiro, RJ, Brazil.
authors.forename: Anke
authors.initials: A
authors.lastname: Bergmann
authors.affiliation: Institute for Studies in Public Health, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Ligia
authors.initials: L
authors.lastname: Bahia
mesh_terms: D006801:Humans; D064702:International Classification of Functioning, Disability and Health; D064887:Observational Studies as Topic