title: Asthma outcomes: symptoms.
abstract: BACKGROUND
  Respiratory symptoms are commonly used to assess the impact of patient-centered interventions.
  
  
  OBJECTIVE
  At the request of National Institutes of Health (NIH) institutes and other federal agencies, an expert group was convened to propose which measurements of asthma symptoms should be used as a standardized measure in future clinical research studies.
  
  
  METHODS
  Asthma symptom instruments were classified as daily diaries (prospectively recording symptoms between research visits) or retrospective questionnaires (completed at research visits). We conducted a systematic search in PubMed and a search for articles that cited key studies describing development of instruments. We classified outcome instruments as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an NIH-organized workshop in March 2010 and finalized in September 2011.
  
  
  RESULTS
  Four instruments (3 daily diaries, 1 for adults and 2 for children; and 1 retrospective questionnaire for adults) were identified. Minimal clinically important differences have not been established for these instruments, and validation studies were only conducted in a limited number of patient populations. Validity of existing instruments may not be generalizable across racial-ethnic or other subgroups.
  
  
  CONCLUSIONS
  An evaluation of symptoms should be a core asthma outcome measure in clinical research. However, available instruments have limitations that preclude selection of a core instrument. The working group participants propose validation studies in diverse populations, comparisons of diaries versus retrospective questionnaires, and evaluations of symptom assessment alone versus composite scores of asthma control.
authors.affiliation: University of Illinois at Chicago, Chicago, IL, USA.
authors.forename: Jerry A
authors.initials: JA
authors.lastname: Krishnan
authors.forename: Robert F
authors.initials: RF
authors.lastname: Lemanske
authors.forename: Glorisa J
authors.initials: GJ
authors.lastname: Canino
authors.forename: Kurtis S
authors.initials: KS
authors.lastname: Elward
authors.forename: Meyer
authors.initials: M
authors.lastname: Kattan
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Matsui
authors.forename: Herman
authors.initials: H
authors.lastname: Mitchell
authors.forename: E Rand
authors.initials: ER
authors.lastname: Sutherland
authors.forename: Michael
authors.initials: M
authors.lastname: Minnicozzi
mesh_terms: D000328:Adult; D001249:Asthma / Q000503:physiopathology* / Q000517:prevention & control / Q000628:therapy; D017028:Caregivers; D002648:Child; D002675:Child, Preschool; D006801:Humans; D008499:Medical Records; D017063:Outcome Assessment, Health Care / Q000592:standards*; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D016896:Treatment Outcome