title: PLATINO, a nine-year follow-up study of COPD in the city of São Paulo, Brazil: the problem of underdiagnosis.
abstract: OBJECTIVE
  To determine the underdiagnosis rate in new COPD cases at the end of a nine-year follow-up period-in the study designated "Projeto Latino-Americano de Investigação em Obstrução Pulmonar" (PLATINO, Latin-American Pulmonary Obstruction Investigation Project)-and compare that with the underdiagnosis rate during the initial phase of the study, as well as to identify the clinical features exhibited by the subjects who were not diagnosed until the end of the follow-up phase.
  
  
  METHODS
  The study population comprised the 1,000 residents of the city of São Paulo, Brazil, who took part in the PLATINO study. Of those, 613 participated in the follow-up phase, during which the subjects were assessed with the same instruments and equipment employed in the initial phase of the study. We used the chi-square test or the independent sample t-test to analyze the underdiagnosis rate and to identify the characteristics of the subjects who were not diagnosed until the end of the follow-up phase.
  
  
  RESULTS
  The underdiagnosis rate for new COPD cases at the end of the nine-year follow-up period was 70.0%. The underdiagnosis rate during the follow-up phase was 17.5% lower than that reported for the initial phase of the study. The subjects who were not diagnosed until the end of the follow-up phase presented with fewer respiratory symptoms, better pulmonary function, and less severe disease than did those previously diagnosed with COPD.
  
  
  CONCLUSIONS
  The underdiagnosis rate for new COPD cases was lower in the follow-up phase of the study than in the initial phase. The subjects who were not diagnosed until the end of the follow-up phase of the PLATINO study presented with the same clinical profile as did those who were not diagnosed in the initial phase. These findings underscore the need for spirometry in order to confirm the diagnosis of COPD and provide early intervention.
authors.affiliation: Federal University of São Paulo, São Paulo, Brazil, Physiotherapist. Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Graciane Laender
authors.initials: GL
authors.lastname: Moreira
authors.affiliation: Federal University of São Paulo, São Paulo, Brazil, Physiotherapist. Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Beatriz Martins
authors.initials: BM
authors.lastname: Manzano
authors.affiliation: São Camilo University Center, Department of Physical Therapy, São Paulo, Brazil, Professor. Department of Physical Therapy, São Camilo University Center, São Paulo, Brazil.
authors.forename: Mariana Rodrigues
authors.initials: MR
authors.lastname: Gazzotti
authors.affiliation: Federal University of São Paulo, Department of Pulmonology, São Paulo, Brazil, Attending Physician, Department of Pulmonology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: Oliver Augusto
authors.initials: OA
authors.lastname: Nascimento
authors.affiliation: Instituto Nacional de Enfermedades Respiratórias, Mexico City, Mexico, Professor. Instituto Nacional de Enfermedades Respiratórias, Mexico City, Mexico.
authors.forename: Rogelio
authors.initials: R
authors.lastname: Perez-Padilla
authors.affiliation: Federal University of Pelotas, School of Medicine, Department of Clinical Medicine, Pelotas, Brazil, Full Professor of Pulmonology. Department of Clinical Medicine, Federal University of Pelotas School of Medicine, Pelotas, Brazil.
authors.forename: Ana Maria Baptista
authors.initials: AM
authors.lastname: Menezes
authors.affiliation: Federal University of São Paulo, Department of Pulmonology, São Paulo, Brazil, Tenured Professor. Department of Pulmonology, Federal University of São Paulo, São Paulo, Brazil.
authors.forename: José Roberto
authors.initials: JR
authors.lastname: Jardim
mesh_terms: D000368:Aged; D015992:Body Mass Index; D001938:Brazil / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000453:epidemiology; D012959:Socioeconomic Factors; D013147:Spirometry; D011795:Surveys and Questionnaires; D014505:Urban Population