Development of Symptom-Based Measures of Acute Otitis Media Severity

Abstract

To the Editors: Shaikh et al1,2 have recently published studies of a parent-reported outcome instrument for clinical trials of AOM (AOM-SOS). Health status outcome measures for AOM are designed to assess key quality-of-life issues such as pain and suffering. Treatments should be evaluated on their effectiveness to relieve symptoms rapidly. A complete discussion of the need to evaluate both traditional medical model outcomes and health status outcomes can be found in the excellent review by Kaplan.3 A gold standard (traditional medical model) outcome measure for AOM clinical trials is pre- and posttreatment culture of the middle ear fluids, obtained by tympanocentesis. Culture data remain a key measure of antibiotic effectiveness in eliminating pathogens from middle ear fluids. Because there was no gold standard for the evaluation of AOM symptoms, we began preliminary work on “ETG-4” (Ear Treatment Group-four symptoms), a paper-and-pencil measure of AOM symptoms, completed by the parent/guardian. Our first study using this scale measured the difference in symptom scores from enrollment to day 3 to 5 in a clinical trial of adjuvant therapy in the treatment of AOM.4 We assessed 4 items: ear ache/tugging, irritability, poor feeding, and fever. These items had been reported in previous studies to be commonly associated with AOM.5 Our results indicated that these items proved an excellent measure of change over time, but we did not show differences in symptom scores between bacterial, bacterial/viral, or no pathogen groups. Subsequently we added sleep disturbance, making the symptom score “ETG-5,” tested it against items abstracted from a preexisting symptom scale (OM-3) and found excellent correlation. ETG-5 was found to be the most responsive measure of change in clinical symptoms when compared against 3 other scales.6 ETG-5 also proved successful in differentiating clinical outcomes in children with nonsevere AOM randomized to watchful waiting versus immediate antibiotic therapy.7 More recently,8 we used ETG-5 to evaluate the clinical status of children with unilateral versus bilateral AOM. No symptom score differences were found. The AOM-SOS items (ear pain, ear tugging, irritability, difficulty sleeping, eating less, less playful, fever) developed by Shaikh et al share similar items as ETG-5 (ear ache/tugging, irritability, sleep disturbance, poor feeding, and fever). We believe that AOM-SOS and ETG-5 have the potential to become important tools in clinical trials, especially when used to compare treatments in randomized studies, where a sensitive instrument is needed. On the other hand, in clinical settings, an analogue (AOM-faces) scale, as published by Friedman et al 2006,6 has more utility for clinical decision making in office practice than a paper-and-pencil questionnaire such as ETG-5. (For an electronic version of AOM-faces, please send your request to Dr. McCormick). In our clinical trial, the AOM-faces scale, when combined with a rating of tympanic membrane characteristics (otoscopic scale, 8 grades), was even more responsive to change than ETG-5.6 It might be interesting to combine ETG-5 or AOM-SOS with otoscopic scale, 8 grades to obtain an even better measure because the combination would use data from both the clinician and the parent (signs and symptoms). We hope further work will clarify this issue. David P. McCormick, MD Tasnee Chonmaitree, MD Department of Pediatrics University of Texas Medical Branch at Galveston Galveston, TX