Responsiveness and minimal clinically important difference for the EQ-5D in chronic rhinosinusitis

BACKGROUND The 5-dimensional EuroQol questionnaire (EQ-5D) is validated to measure general health-related quality of life (QOL). Our objective was to determine the responsiveness and minimal clinically important difference (MCID) of the EQ-5D health utility value (EQ-5D HUV) and visual analog scale (EQ-5D VAS) in chronic rhinosinusitis (CRS). METHODS 203 adults undergoing medical management for CRS were prospectively recruited. General health-related QOL (using EQ-5D HUV and EQ-5D VAS) and CRS-specific QOL (using the 22-item Sinonasal Outcome Test [SNOT-22]) were measured at enrollment and a subsequent follow-up time point 2-12 months later. At follow-up, participants also rated change in general health as Much worse, A little worse, About the same, A little better or Much better compared to enrollment. The EQ-5D HUV and EQ-5D VAS MCIDs were calculated using distribution-based, anchor-based, and receiver operator characteristic (ROC) curve-based methods. RESULTS Change in SNOT-22 score was correlated with EQ-5D HUV and EQ-5D VAS change. Using the different methods of calculating MCID, we find the EQ-5D HUV MCID to be 0.04 and EQ-5D VAS MCID to be 8.0. The calculated EQ-5D MCIDs had approximately a sensitivity of 40-50% and specificity of 80% in detecting patients experiencing noticeable improvement in general health. CONCLUSIONS The EQ-5D responds well to changing CRS symptomatology. We propose MCIDs for EQ-5D HUV of 0.04 and EQ-5D VAS of 8 in CRS patients, which although specific, are not sensitive for detecting patients experiencing improvement in general health.