title: An electronic diary is shown to be more reliable than a paper diary: results from a randomized crossover study in patients with persistent asthma.
abstract: OBJECTIVE
  Test-retest reliability of an asthma paper diary versus an electronic diary (e-diary) with an integrated peak flow meter was investigated. The equivalence of the two modes was also evaluated.
  
  
  METHODS
  Prospective, randomized crossover study design in adolescents (12-17 years) and adults (≥18 years). Key inclusion criteria were persistent asthma, Asthma Control Test (ACT) scores ≥16, use of inhaled corticosteroid with or without long-acting beta-agonist for ≥12 weeks, nocturnal awakenings <2 times in the past week, and activity limitations <1 per week. Participants were randomized to either paper then e-diary or e-diary then paper, to be completed for 14 days each.
  
  
  RESULTS
  Forty-seven participants completed all study visits. Weekly percentage of symptom-free days (SFDs) and rescue-free days (RFDs) were calculated. Intraclass correlation coefficients (ICCs) of Week 1 mean SFD and RFD (test) and Week 2 mean SFD and RFD (retest), respectively, were estimated in three groups defined as stable: (i) minimal changes in asthma symptoms, as measured by the global patient reported symptom change question, (ii) less than 15% change (absolute value) in 1 second FEV(1) at adjacent study visits, and (iii) changes in ACT scores less than three points for each mode. SFD demonstrated acceptable ICC (≥0.70) using all three definitions of asthma stability for both modes.
  
  
  CONCLUSIONS
  Acceptable reproducibility of the percentage of RFD (ICC = 0.78) was only observed for the e-diary using the FEV(1) stability criterion. The ICCs for SFD and RFD were acceptable, 0.84 and 0.70, respectively, suggesting better reliability for the e-diary.
authors.affiliation: Outcomes Research, United BioSource Corporation, Bethesda, MD, USA.
authors.forename: Andrea M
authors.initials: AM
authors.lastname: Ireland
authors.forename: Ingela
authors.initials: I
authors.lastname: Wiklund
authors.forename: Ray
authors.initials: R
authors.lastname: Hsieh
authors.forename: Peter
authors.initials: P
authors.lastname: Dale
authors.forename: Erin
authors.initials: E
authors.lastname: O'Rourke
mesh_terms: D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000627:therapeutic use*; D000318:Adrenergic beta-Agonists / Q000008:administration & dosage / Q000627:therapeutic use*; D000328:Adult; D001249:Asthma / Q000188:drug therapy* / Q000503:physiopathology*; D002648:Child; D018592:Cross-Over Studies; D003625:Data Collection / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D015203:Reproducibility of Results; D057566:Self Report; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: D000305:Adrenal Cortex Hormones; D000318:Adrenergic beta-Agonists