Validation of an outcomes instrument for tonsil and adenoid disease

Objective: To design and validate a disease-specific health status instrume nt-the Tonsil and Adenoid Health Status Instrument-for use in children with tonsil and adenoid disease. Design: Prospective psychometric and clinimetric instrument validation in 3 stages. Settings: A tertiary academic pediatric specialty hospital and a tertiary a cademic hospital, in 2 different cities. Patients/Other Participants: Children with tonsil and adenoid disease prese nting for evaluation and treatment(n=224). Intervention/Method: Prospective instrument validation. Stage 1 consisted o f initial item testing, reduction, and subscale construction; stage 2, reli ability and validity testing, factor analysis, and final item reduction; an d stage 3, responsiveness analysis. Main Outcome Measures: Test-retest and internal consistency reliability; co ntent, construct, and criterion validity; orthogonal principal components f actor analysis; and response sensitivity analysis. Results: Factor analysis and item analysis confirmed 6 distinct subscales m easuring different constructs (aspects) of disease-specific health status t hat are affected by tonsil and adenoid disease: eating and swallowing, airw ay and breathing, infections, health care utilization, cost of care, and be havior. For each subscale, the Tonsil and Adenoid Health Status Instrument demonstrated excellent test-retest reliability (r=0.72-0.88) and internal c onsistency reliability (Cronbach alpha=.73-.87). Content validity was ensur ed during the design process. Construct validity was demonstrated by means of convergent and divergent validity with a global quality-of-life instrume nt (the Child Health Questionnaire, version PF28). Criterion validity was a lso satisfactory. Finally, the instrument was appropriately sensitive, with high standardized response means and effect sizes. Conclusions: The Tonsil and Adenoid Health Status Instrument is a valid, re liable, and sensitive instrument with 6 distinct subscales. This instrument has significant utility for outcomes research in children with tonsil and adenoid disease.