title: Patterns of asthma control: a 3-year analysis of patient claims.
abstract: BACKGROUND
  The goal of asthma therapy is to maintain consistent control.
  
  
  OBJECTIVE
  We sought to examine the patterns of asthma control recorded over 3 years using administrative claims and resource utilization definition.
  
  
  METHODS
  We performed a retrospective observational study with a nationally representative patient-level database containing pharmacy and medical claims. Patients with asthma (International Classification of Diseases, Ninth Revision-Clinical Modification code 493.xx), patients undergoing treatment with at least 1 asthma medication, and patients with 36 months of continuous claims coverage during the calendar years 1996 through 2002 were identified. A total of 63,324 patients were included in the study. Patients were classified as having controlled asthma in year 1 if they had less than 4 claims for a short-acting beta 2 -agonist, no claims for an OCS, and no asthma-related emergency department visits or hospitalizations. Patients were then followed over the next 8 quarters (2 years) to observe whether control was maintained. Control during a quarter was defined with the same criteria, except the reliever threshold was adjusted to 2 or more claims per quarter.
  
  
  RESULTS
  Thirty-nine thousand ninety-five (57%) patients were defined as having controlled asthma during year 1. During the 2-year follow-up period, a range of 10% to 14% of these patients with controlled asthma met the criteria of uncontrolled asthma during any given quarter. Overall, 46,227 (73%) patients identified met the criteria for uncontrolled asthma at least once during the 3-year period.
  
  
  CONCLUSIONS
  This study demonstrates that almost 75% of asthmatic patients experience an uncontrolled asthma episode 1 or more times over a 3-year period. Furthermore, we found that significant fluctuations in asthma control exist, even in patients with prior controlled asthma.
authors.affiliation: Infomed Northwest and University of Washington, Seattle, USA. econmed@msn.com
authors.forename: David A
authors.initials: DA
authors.lastname: Stempel
authors.forename: Trent P
authors.initials: TP
authors.lastname: McLaughin
authors.forename: Richard H
authors.initials: RH
authors.lastname: Stanford
authors.forename: Anne L
authors.initials: AL
authors.lastname: Fuhlbrigge
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000517:prevention & control*; D002648:Child; D003628:Database Management Systems; D005260:Female; D006801:Humans; D008297:Male; D008404:Massachusetts; D008875:Middle Aged; D012189:Retrospective Studies