title: Asthma severity in primary care asthma patients: a comparative study of four different approaches to severity classification.
abstract: OBJECTIVE
  To explore the factor structure of asthma severity and asthma control and to compare the results of different approaches to asthma severity classification on the distribution of costs of asthma medication.
  
  
  METHODS
  Comparison of four different approaches to asthma severity classification and factor analysis of asthma control descriptors. A correlation analysis between costs and the different approaches to severity classification was performed.
  
  
  RESULTS
  The factor analysis suggests that asthma control consists of at least two factors. Four approaches to severity classification were explored and all except the 'GINA EXPANDED' classification tended to place patients in the most severe category. The pharmaceutical costs varied between 0 and 75 SEK per day (0 and 5.31 GBP; 0 and 7.68 EURO).
  
  
  CONCLUSIONS
  There is a considerable overlap between asthma control and asthma severity. None of the approaches used in this study present a superior satisfactory solution to the classification problem.
authors.affiliation: Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Marianne Heibert
authors.initials: MH
authors.lastname: Arnlind
authors.forename: Mika
authors.initials: M
authors.lastname: Nokela
authors.forename: Per-Olof
authors.initials: PO
authors.lastname: Ehrs
authors.forename: Eva
authors.initials: E
authors.lastname: Wikström Jonsson
mesh_terms: D018927:Anti-Asthmatic Agents / Q000191:economics / Q000627:therapeutic use; D001249:Asthma / Q000145:classification* / Q000175:diagnosis / Q000188:drug therapy; D016527:Drug Costs; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011320:Primary Health Care; D011788:Quality of Life; D012129:Respiratory Function Tests; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
chemical_list: D018927:Anti-Asthmatic Agents