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.
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.
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).
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.
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.
Accepted for publication September 6, 2014.
The authors have no conflicts of interest to disclose.
Address for correspondence: Nader Shaikh, MD, MPH, Division of General Academic Pediatrics, University of Pittsburgh School of Medicine, Children’s Hospital of Pittsburgh of UPMC, One Children’s Hospital Drive, 4401 Penn Avenue, Pittsburgh, PA 15224. E-mail: email@example.com.