Acute Otitis Media Severity of Symptom Scale (AOM-SOS) Development and Validation Nader Shaikh, MD Alejandro Hoberman, MD Jack Paradise, MD Howard Rockette, PhD* General Academic Pediatrics Childrens Hospital of Pittsburgh *Graduate School of Public Health

Why measure symptoms? Symptoms are important Bring children to medical attention AOM treated to improve symptoms Need for symptom measurement in AOM trials Current research limited due to lack of validated symptom measurement strategy Use of surrogate outcomes (bacteriologic eradication) problematic

Potential uses Comparison of treatment modalities Natural history of symptoms in AOM Relationship between bacteriology and symptoms Relationship between otoscopy and symptoms

Conceptual model

Scale Development List of 28 symptoms Reduction using triangulation Literature review Expert opinion Parent interview (n=33) Which of 28 symptoms present How much symptom affects child

Validation study # 1 Objective Establish the reliability, validity and responsiveness of SOS by comparing it with otoscopy Methods Cohort of children 6-24 mo with/without AOM (n = 327) 2003 and 2004 respiratory seasons Followed for one season (~3 visits/child, 949 visits) At each visit - Examined by validated otoscopist - SOS completed

Internal Reliability Definition Are items in scale measuring the same concept? Methods Correlation of items with each other Assessed by Cronbachs α Cronbachs α >0.7 indicates good reliability Results α = 0.83 Excellent inter-item correlation given short scale and heterogeneous population

Content Validity Definition Does each item measure what it is supposed to? Are items associated with AOM (or URI)? Methods Examined association between items and otoscopic diagnosis adjusting for URI

Content validity AOM vs. No AOM AOM vs. OME OME vs. Normal Ear painp <.001 p =.14 Tuggingp <.001 p =.02 Irritability/cryingp <.001 p =.049 Difficulty sleepingp <.001 p =.09 Eating lessp <.001p <.004p =.08 Less playfulp <.001p =.01p =.04 *All p values adjusted for URI

Construct Validity Otoscopic diagnosis AOM N = 211 OME N = 154 NORMAL N = 584 Mean AOM-SOS score Standard Deviation AOM vs. Normal p <.001 AOM vs. OME p <.001 OME vs. Normalp <.03 Does the scale measure what it is supposed to?

Responsiveness Definition Can the scale detect change? Methods Examined changes in score in children seen twice in 3-week period Responsiveness measured by standardized response mean (SRM) SRM > 0.5 good responsiveness

Responsiveness – Change in score within 3-week period UnchangedChanged No AOM N = 24 AOM N = 38 No AOM AOM N = 23 AOM No AOM N = 108 MeanStdMeanStdMeanStdMeanStd Change P value.57.08<.001 SRM

Study # 2 – Further Validation Needed to further evaluate: Day-to-day responsiveness Construct validity Design Cohort study 3 mo to 3 yr with AOM treated with antibiotics Otoscopic exam on days 1 and 5 SOS administered days 1 through 5 (q 12 hrs) Reference measures also administered 56 children enrolled

Construct validity Correlation of SOS with reference measures on day 1 Reference MeasuresAOM-SOSp value Pain Visual analog scaler =.71<.05 Post operative pain scale r =.83<.05 Functional status IIR ¥ r =.88<.05 Chambers ¥ Stein

Responsiveness – Change in score Standardized response mean (day 1 to 5) = 0.76 AOM-SOS score

Conclusions Developed scale for measurement of AOM symptoms Demonstrated: -Good measurement properties -Correlates with otoscopy -Correlates with validated measures of pain and functional status Anticipated use in NIH funded RCT to evaluate the efficacy of antibiotics versus placebo in young children with AOM

Acknowledgements Consultants Gordon Guyatt, MD – McMaster U. Galen Switzer, PhD – U. of Pittsburgh Study Team Diana Kearney, Study Coordinator Kathleen Colborn, Data Manager Lisa Zoffel, CRNP Stephanie Konieczka, RN