Concordance in diagnosis of diabetic retinopathy by fundus photography between retina specialists and a standardized reading center. Mexico City Diabetes Study Retinopathy Group.

Proper detection and adequate laser therapy of diabetic retinopathy (DR) using guidelines established by landmark studies is important to prevent blindness. We analyzed the agreement between diagnostic classification of DR as determined by certified retina specialists compared with standardized readings of fundus photographs performed by the Fundus Photograph Reading Center (FPRC) of the University of Wisconsin. Color fundus stereophotographs of seven standard fields of each eye of 15 diabetics were sent to FPRC and to 11 retina specialists practicing in Mexico City and representing the major health care institutions. These centers are sites for training programs in ophthalmology. In addition, leading specialists in private practice were invited to participate. Their diagnostic criteria were surveyed. Information was collected using a specially designed form on which the investigator entered his/her diagnostic classification using his/her clinical judgment. Mean overall percent agreement was 74%. Kappa statistic, which corrects for chance agreement, was between 0.29-0.87 with a mean of 0.53. Weighted kappa measuring level of disagreement was between 0.34-0.90, mean 0.57. Data were analyzed separately for macular edema and for this end point the weighted kappa statistic was 0.68. Based on conventional interpretation of the kappa statistic, these mean values are in the range of fair agreement. However, since there is a significant discrepancy in the concordance level observed, there is a need for promoting further applications of internationally accepted diagnostic criteria to assure optimal therapy.