Accuracy of trained rural ophthalmologists versus non-medical image graders in the diagnosis of diabetic retinopathy in rural China

Background/aims To determine the diagnostic accuracy of trained rural ophthalmologists and non-medical image graders in the assessment of diabetic retinopathy (DR) in rural China. Methods Consecutive patients with diabetes mellitus were examined from January 2014 to December 2015 at 10 county-level facilities in rural Southern China. Trained rural ophthalmologists performed a complete eye examination, recording diagnoses using the UK National Diabetic Eye Screening Programme (NDESP) classification system. Two field, mydriatic, 45 degrees digital photographs were made by nurses using NDESP protocols and graded by trained graders with no medical background using the NDESP system. A fellowship-trained retina specialist graded all images in masked fashion and served as reference standard. Results Altogether, 375 participants (mean age 6010 years, 48% men) were examined and 1277 imageswere graded. Grader sensitivity (0.82-0.94 (median 0.88)) and specificity (0.91-0.99 (median 0.98)), reached or exceeded NDESP standards (sensitivity 80%, specificity 95%) in all domains except specificity detecting any DR. Rural ophthalmologists' sensitivity was 0.65-0.95 (median 0.66) and specificity 0.59-0.95 (median 0.91). There was strong agreement between graders and the reference standard (kappa=0.84-0.87, p<0.001) and weaktomoderate agreement between rural doctors and the reference (kappa=0.48-0.64, p<0.001). Conclusion This is the first study of diagnostic accuracy in DR grading among non-medical graders or ophthalmologists in low-income and middle-income countries. Non-medical graders can achieve high levels of accuracy, whereas accuracy of trained rural ophthalmologists is not optimal.