title: Change in asthma control over time: predictors and outcomes.
abstract: BACKGROUND
  Maintenance of asthma control over time is a clear goal of national asthma guidelines, but few studies have addressed the natural history of asthma control over time.
  
  
  OBJECTIVE
  To assess the impairment domain of asthma control over time in patients with persistent asthma and to determine predictors and consequences of controlled and uncontrolled asthma over time.
  
  
  METHODS
  Patients 18-56 years old with persistent asthma who completed baseline (November 2007) and follow-up asthma surveys (April, July, October 2008) were included in the study. The survey included the Asthma Control Test as well as questions regarding other patient and asthma characteristics. Health care utilization (pharmacy and exacerbations) for 2008 was obtained from administrative data.
  
  
  RESULTS
  The baseline and first follow-up surveys were completed by 1267 patients, and all 4 surveys were completed by 782 patients. Patients with well-controlled asthma at baseline were significantly more likely (P < .0001) to have well-controlled asthma over the following year (76.2%-80.4%) than patients with uncontrolled asthma at baseline (33.5%-36.9%). Patients whose asthma control improved over the first several months of follow-up experienced significantly (P < .05) fewer exacerbations over the subsequent year than patients with initially uncontrolled asthma who did not improve.
  
  
  CONCLUSIONS
  Degree of asthma control at one point in time is strongly related to the achievement or maintenance of control and to asthma exacerbations over time. Patients with uncontrolled asthma, especially very poorly controlled asthma, should receive intensive management and follow-up in an attempt to achieve well-controlled asthma over time.
authors.affiliation: Department of Allergy, Kaiser Permanente Medical Center, San Diego, Calif. Electronic address: michael.x.schatz@kp.org.
authors.forename: Michael
authors.initials: M
authors.lastname: Schatz
authors.affiliation: Department of Allergy, Kaiser Permanente Medical Center, San Diego, Calif.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Zeiger
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Medical Center, Pasadena, Calif.
authors.forename: Su-Jau
authors.initials: SJ
authors.lastname: Yang
authors.affiliation: Department of Research and Evaluation, Kaiser Permanente Medical Center, Pasadena, Calif.
authors.forename: Wansu
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Allergy, Kaiser Permanente Medical Center, San Diego, Calif.
authors.forename: William
authors.initials: W
authors.lastname: Crawford
authors.affiliation: Department of Global Health Outcomes, Merck & Co Inc, West Point, Pa.
authors.forename: Shiva
authors.initials: S
authors.lastname: Sajjan
authors.affiliation: Department of Global Health Outcomes, Merck & Co Inc, West Point, Pa.
authors.forename: Felicia
authors.initials: F
authors.lastname: Allen-Ramey
mesh_terms: D000293:Adolescent; D000328:Adult; D018927:Anti-Asthmatic Agents / Q000627:therapeutic use*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology; D016009:Chi-Square Distribution; D018450:Disease Progression; D011307:Drug Prescriptions; D017723:Drug Utilization Review; D005260:Female; D019538:Health Care Surveys; D006295:Health Resources / Q000706:statistics & numerical data; D006304:Health Status; D006305:Health Status Indicators; D006801:Humans; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010593:Pharmaceutical Services / Q000706:statistics & numerical data; D012307:Risk Factors; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D018927:Anti-Asthmatic Agents
keywords: ACT; Asthma; Asthma Control Test; Asthma control; Asthma exacerbations; Asthma follow-up; BMI; Body mass index; CI; Confidence interval; ED; Emergency department; Maintenance of asthma control; SABA; Short-acting β-agonist