Modification of the acute otitis media symptom severity scale.

OBJECTIVE

To modify a parent-reported scale we developed to follow symptoms of young children with acute otitis media (AOM-SOS) with the aim of improving its psychometric properties.

STUDY DESIGN

We modified version 4.0 of the scale by increasing the number of response options from 3 to 6. We compared the distribution of scores, internal reliability, construct validity, and responsiveness of versions 4.0 and 5.0 in children diagnosed with acute otitis media (AOM) in 2 studies. For Version 5.0, we also estimated the minimal important difference (MID) and assessed its construct validity.

RESULTS

291 and 70 children were enrolled in the studies evaluating version 4.0 and 5.0, respectively. Version 5.0 had fewer items at the ceiling and better psychometric properties (responsiveness, internal reliability, and test-retest reliability). Changes in the score for Version 5.0 corresponded to changes in clinical status. Factor analysis supported a one-factor solution. Children whose parents reported only a small degree of improvement on the diary (compared to the day before) had a mean decrease in AOM-SOS score of approximately 20%. This value can be used as the MID for this version of the scale.

CONCLUSIONS

Modification of the AOM-SOS improved its psychometric properties. Data presented here support the use of Version 5.0 of the AOM-SOS as a measure of change in symptom burden in clinical trials of children with acute otitis media.