RESUMO
INTRODUCTION: Uveitis is the inflammation of the middle layer of the eye, the uvea, and is a major cause of blindness. None of the instruments used in clinical practice are, in themselves, sufficient to evaluate the course of uveitis. Therefore, it is necessary to develop instruments enabling standardized measurement of inflammatory activity. We developed a composite disease activity index for patients with uveitis known as UVEDAI, which considers the overall activity of the eye. The objective of this study was to validate the composite index of ocular inflammation, UVEDAI. METHODS: A multicenter cross-sectional study involving eight Spanish tertiary hospitals. Sixty-two patients aged ≥ 18 years with acute uveitis were recruited. Participants gave informed consent before participating in the study. A full ophthalmological examination was performed by two ophthalmologists to determine inflammatory activity: one used the UVEDAI score and the other used clinical judgment. The ophthalmologists did not share their findings with each other to avoid introducing bias into the analysis. Construct validity was established by means of factor analysis. The criterion validity of the index was determined using an ordinal multivariate regression model, in which the dependent variable was the degree of uveal inflammation (mild, moderate, or high/severe). Cut-off points were determined for the UVEDAI and for the receiver operating characteristic (ROC) curves. RESULTS: Sixty-two patients were included. Total variance with the three components accounted for 80.32% of the construct validity. Each of the three components identified one type of eye involvement. The discriminatory capacity of UVEDAI was 0.867 (95% CI 0.778; 0.955 p < 0.001) for mild versus moderate-high and 0.946 (95% CI 0.879; 1.000 p < 0.001) for high versus mild-moderate. CONCLUSIONS: The variables included in UVEDAI enable ocular inflammatory activity to be described with a high degree of accuracy. The index may be used to evaluate and classify this activity with considerable discriminatory power.