title: Determination of the minimal important difference for the acute otitis media severity of symptom scale.
abstract: BACKGROUND
  We previously developed and validated the acute otitis media severity of symptom (AOM-SOS) scale for rating symptoms of AOM in young children. In this report, we sought to estimate the minimal important difference (MID) for change in AOM-SOS scores.
  
  
  METHODS
  In a group of children 6-24 months of age with AOM enrolled in a recently reported placebo-controlled clinical trial of antibiotic efficacy, we compared changes in AOM-SOS scores with parental assessments of change over a 24-hour period. Mean absolute and mean relative change in scores in children reportedly exhibiting only a small degree of improvement were considered in arriving at an estimated MID. We then compared the proportions of children in the antibiotic and placebo groups, respectively, whose AOM-SOS scores changed more than the estimated MID at various time points after enrollment.
  
  
  RESULTS
  Data were available for 277 children. Children whose parents reported only a small degree of improvement 24 hours after enrollment had a mean decrease in AOM-SOS score of 3.8, or 55%, from baseline. We found the relative decrease more telling than the absolute decrease. The proportions of children in the antibiotic and placebo groups, respectively, whose AOM-SOS scores had decreased <55% on Day 7 were 12.3 and 23.8% (P=0.02), and during Days 4-7 were 28 and 40% (P=0.046).
  
  
  CONCLUSIONS
  We estimated the MID for change in AOM-SOS scores in young children and described use of the MID as an added metric in interpreting results from a clinical trial of antibiotic efficacy.
authors.affiliation: From the *Division of General Academic Pediatrics, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine; and †Department of Biostatistics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA.
authors.forename: Nader
authors.initials: N
authors.lastname: Shaikh
authors.forename: Howard E
authors.initials: HE
authors.lastname: Rockette
authors.forename: Alejandro
authors.initials: A
authors.lastname: Hoberman
authors.forename: Marcia
authors.initials: M
authors.lastname: Kurs-Lasky
authors.forename: Jack L
authors.initials: JL
authors.lastname: Paradise
mesh_terms: D000208:Acute Disease; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010033:Otitis Media / Q000175:diagnosis* / Q000188:drug therapy; D010290:Parents; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
chemical_list: D000900:Anti-Bacterial Agents