title: Symptoms and markers of symptom severity in asthma--content validity of the asthma symptom diary.
abstract: OBJECTIVE
  The American Thoracic Society/European Respiratory Society (ATS/ERS) Task Force acknowledged the multi-faceted nature of asthma in its recent definition of asthma control as a summary term capturing symptoms, reliever use, frequency/severity of exacerbations, lung function, and future risk and the Global Initiative for Asthma (GINA) defines the clinical manifestations (well established markers of asthma severity) of asthma to include symptoms, sleep disturbances, limitations of daily activity, impairment of lung function, and use of rescue medications. The objectives of this qualitative work were to identify symptoms and markers of symptom severity relevant to patients with moderate to severe asthma and to evaluate the content validity of the asthma symptom diary (ASD).
  
  
  METHODS
  A qualitative interview study was conducted using a purposive sample of symptomatic adult and adolescent (≥12 years) subjects with asthma. Concept elicitation (CE) interviews (n = 50) were conducted to identify core asthma symptoms and symptom-related clinical markers, followed by cognitive interviews (n = 24) to ensure patient comprehension of the items, instructions and response options. CE interviews were coded using ATLAS.ti for content analysis.
  
  
  RESULTS
  The study sample had a diverse range of symptom severity, level of symptom control, sociodemographic and socioeconomic status. The most frequently reported symptoms in adults were chest tightness (n = 33/34; 97.1%), wheezing (n = 31; 91.2%), coughing (n = 30; 88.2%), and shortness of breath (n = 25; 73.5%); in adolescents they were wheezing (n = 14/16; 87.5%), coughing (n = 13; 81.3%), and chest tightness (n = 11; 68.8%). Adults identified chest tightness followed by shortness of breath as their most severe symptoms; while adolescents reported coughing and chest tightness as their most severe symptoms. Sleep awakenings and limitations in day-to-day activities were frequent symptom-related clinical markers. Day-to-day variability and differences between daytime and nighttime symptom experiences reported by subjects resulted in the need for the ASD to be administered twice daily. Cognitive interviews indicated that subjects found the revised ASD items clear and easy to understand.
  
  
  CONCLUSIONS
  This study supports the content validity of the revised ASD, showing it to be consistent with patient experiences and ready for further psychometric testing.
authors: Global Health Economics, Amgen Inc., One Amgen Center Drive MS 28-3-A, Thousand Oaks, CA, 91320, USA. gglobe@amgen.com.
authors: Gary
authors: G
authors: Globe
authors: Health Research Associates, Inc., 6505 216th St SW, Mountlake Terrace, WA, 98043, USA. martin@hrainc.net.
authors: Mona
authors: M
authors: Martin
authors: Department of Allergy, Kaiser Permanente Medical Center, 4647 Zion Ave, San Diego, CA, 92120, USA. michael.x.schatz@kp.org.
authors: Michael
authors: M
authors: Schatz
authors: Evidera, Metro Building, 6th Floor, 1 Butterwick, London, W6 8DL, UK. ingela.wiklund@evidera.com.
authors: Ingela
authors: I
authors: Wiklund
authors: Global Health Economics, Amgen Inc., One Amgen Center Drive MS 28-3-A, Thousand Oaks, CA, 91320, USA. joseph.lin@gilead.com.|Currently with Gilead Sciences, Inc., Foster City, CA, USA. joseph.lin@gilead.com.
authors: Joseph
authors: J
authors: Lin
authors: Evidera, Metro Building, 6th Floor, 1 Butterwick, London, W6 8DL, UK. robyn.vonmalzahn@evidera.com.
authors: Robyn
authors: R
authors: von Maltzahn
authors: Evidera, 7101 Wisconsin Ave, Suite 600, Bethesda, MD, 20814, USA. maria.mattera@evidera.com.
authors: Maria S
authors: MS
authors: Mattera
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000150:complications / Q000503:physiopathology*; D002637:Chest Pain / Q000209:etiology; D015897:Comorbidity; D003371:Cough / Q000209:etiology; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D011594:Psychometrics; D036301:Qualitative Research; D011788:Quality of Life / Q000523:psychology*; D012720:Severity of Illness Index; D012893:Sleep Wake Disorders / Q000209:etiology