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Why measure symptoms?

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 Children’s Hospital of Pittsburgh *Graduate School of Public Health. Why measure symptoms?.

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Why measure symptoms?

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  1. Acute Otitis Media Severity of Symptom Scale (AOM-SOS) Development and ValidationNader Shaikh, MDAlejandro Hoberman, MDJack Paradise, MDHoward Rockette, PhD*General Academic PediatricsChildren’s Hospital of Pittsburgh*Graduate School of Public Health

  2. 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

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

  4. Conceptual model

  5. 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

  6. 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

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

  8. 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

  9. Content validity *All p values adjusted for URI

  10. Construct Validity Does the scale measure what it is supposed to? AOM vs. Normal p < .001 AOM vs. OME p < .001 OME vs. Normal p < .03

  11. 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

  12. Responsiveness – Change in score within 3-week period

  13. 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

  14. Construct validity † Chambers ¥ Stein

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

  16. 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

  17. 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

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