Objective: To evaluate interobserver agreement between investigator and Reading Center classification of retinal vein occlusion. Design: The Standard Care versus COrticosteroid in REtinal Vein Occlusion (SCORE) Study includes 2 multicenter phase 3 randomized clinical trials evaluating the efficacy and safety of intravitreal triamcinolone: one involves participants with central retinal vein occlusion (CRVO) and one for participants with branch retinal vein occlusion (BRVO). Eyes with hemiretinal vein occlusion (HRVO) were classified as BRVO. Participants: A total of 682 SCORE Study participants, including 271 with CRVO and 411 with BRVO. Methods: Participants were enrolled in each trial on the basis of investigator classification of retinal vein occlusion. Definitions of CRVO, BRVO, and HRVO based on clinical findings were specified in the study protocol. At baseline, 7-field color stereoscopic fundus photographs of the study eye of each participant were forwarded to the University of Wisconsin Fundus Photograph Reading Center (Reading Center) for evaluation. Main Outcome Measures: Percent agreement and kappa statistics comparing investigator and Reading Center classification of retinal vein occlusion type. Results: With HRVO categorized as BRVO (consistent with the SCORE Study design), there was 98.0% agreement between investigator and Reading Center classification (641/654 eyes; kappa = 0.96; 95% confidence interval, 0.94-0.98). Disagreements were fairly evenly divided between classification of an eye as CRVO by the investigator and as BRVO by the Reading Center (7/13 disagreements) and vice versa (6 disagreements). When all 3 disease categories (CRVO, BRVO, and HRVO) were compared, there was 92.2% agreement (603/654; unweighted kappa = 0.86; 95% confidence interval, 0.83-0.90). Most disagreements (38/51, or 74.5%) were between BRVO and HRVO, with 9 between CRVO and BRVO, and 4 between HRVO and CRVO. In univariate analyses, baseline factors significantly associated with disagreement include larger area of capillary loss and black race; black race was the only significant factor in a multivariate analysis. Conclusions: Investigator and Reading Center agreement was excellent in the SCORE Study; disease classification would have been altered in only 13 eyes (2.0%) had Reading Center eligibility been required. Interobserver agreement was least for classification between BRVO and HRVO. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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