Evaluation of the psychometric properties of the endoscopic endonasal sinus and skull base surgery questionnaire (EES-Q) in a prospective cohort study

Objectives: The patients' perspective on health has become increasingly important when assessing treatment outcomes. Recently, the Endoscopic Endonasal Sinus and Skull Base Surgery Questionnaire (EES-Q) was developed to determine the impact of endoscopic endonasal surgery on health-related quality of life (HRQoL). The aim of this study was to evaluate the test-retest reliability, construct validity and responsiveness of the EES-Q. Design: Prospective cohort study. Setting: University Medical Center Groningen, tertiary referral hospital, the Netherlands. Participants: One hundred patients who underwent endoscopic endonasal surgery because of sinus or anterior skull base pathology. Main outcome measures: Test-retest reliability, construct validity and responsiveness. Results: The EES-Q domains exhibited good test-retest reliability (ICC > 0.90). Construct validity was corroborated by significant positive and negative correlations between the EES-Q and the Sino-Nasal Outcome Test-22 (SNOT-22) and postoperative health status (P < 0.01) respectively. The correlation between the social EES-Q domain and the ability to move and perform usual activities (EuroQol-5D-3L [EQ-5D-3L]) was significant positive (P < 0.01). In patients with paranasal sinus pathology, the EES-Q was responsive to clinical change (Cohen's d = 0.6). Conclusion: The EES-Q is a reliable and acceptable responsive disease-specific HRQoL instrument. The expected construct validity of the EES-Q is supported by the results in this study. Inconveniences in social functioning had the greatest negative impact on postoperative health status rating. This reflects the importance of a multidimensional HRQoL assessment after EES. The results indicate that the EES-Q is a promising disease-specific tool for the HRQoL assessment after endoscopic endonasal sinus or anterior skull base surgery.