Comparison of two disease-specific instruments assessing health-related quality of life in patients with chronic otitis media

Purpose Evaluating the current health state in chronic otitis media (COM), audiologic results are complemented by subjective outcomes, such as health-related quality of life (HRQoL). Two disease-specific instruments assessing HRQoL in COM in German-speaking patients exist, i.e., the chronic otitis media outcome test (COMOT-15) and the Zurich chronic middle ear inventory (ZCMEI-21). Since the psychometric properties of these questionnaires in a concurrent application are unknown, the aim of this study was to compare the COMOT-15 and the ZCMEI-21. Methods HRQoL was assessed in adult COM patients using the COMOT-15 and the ZCMEI-21. Psychometric properties were determined, including response distribution, concurrent validity, internal consistency, correlation to hearing and gender differences. Results In 173 patients (mean age 51.5 years), both questionnaires showed normally distributed scores without strong floor and ceiling effects. The total scores and subscores of both questionnaires exhibited satisfactory internal consistency (Cronbach's alpha 0.7-0.9) with the exception of the COMOT-15 hearing subscore (alpha = 0.94) and the ZCMEI-21 medical resource subscore (alpha = 0.66). Fair correlations between the air conduction pure-tone average and the total scores were found (COMOT-15: r = 0.36, p < 0.0001; ZCMEI-21: r = 0.34, p < 0.0001). Conclusion In the first study comparing the COMOT-15 and the ZCMEI-21, both questionnaires exhibited satisfactory psychometric properties with several subtle differences. The COMOT-15 has a strong focus on hearing with a probably redundant content of the hearing subscore and may be suited for hearing-focused research questions. The ZCMEI-21 provides a comprehensive assessment of the COM symptom complex and may therefore also be used in research settings, where ear discharge, vertigo or pain should be covered.