Translation and validation of the Tonsillectomy Outcome Inventory 14 into Danish.

INTRODUCTION: No Danish validated patient-reported outcome measure (PROM) exises for assessing throat-related quality of life in patients with recurrent acute tonsillitis (RT) and chronic tonsillitis (CT). We aimed to translate and linguistically validate the Tonsillectomy Outcome Inventory 14 (TOI-14) into Danish and describe scores in RT and CT patients before and after tonsillectomy as well as in healthy controls. METHODS: We followed the guideline for PROM translation and cultural adaption set out by the Quality of Life Special Interest Group - Translation and Cultural Adaptation group formed by ISPOR. We included RT and CT patients undergoing elective tonsillectomy, who answered the questionnaire pre- and post-operatively (six-month follow-up) as well as healthy controls who answered the questionnaire once. RESULTS: A Danish version of the TOI-14 was developed according to the guideline. A total of 49 RT patients, 34 CT patients and 67 controls were included in the final analysis. Preoperatively, RT and CT patients had markedly higher TOI-14 scores than controls (mean total scores: RT: 45.6; CT: 21.7; controls: 8.9, both p less-than 0.001). Post-operatively, scores fell to levels similar to those of controls (RT: 10.2, p = 0.51; CT: 4.7, p = 0.05). CONCLUSION: We translated, culturally adapted and linguistically validated the Danish version of the TOI-14, finding scores in RT patients, CT patients and controls similar to those recorded by previous studies in German, English and Finnish. FUNDING: The Lundbeck Foundation, grant #R185-2014-2482. TRIAL REGISTRATION: Central Denmark Region #1-16-02-723-20.