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Accuracy of trained rural ophthalmologists versus non-medical image graders in the diagnosis of diabetic retinopathy in rural China
  1. Martha McKenna1,2,
  2. Tingting Chen1,3,
  3. Helen McAneney2,4,
  4. Miguel Angel Vázquez Membrillo1,5,
  5. Ling Jin1,
  6. Wei Xiao1,
  7. Tunde Peto2,
  8. Mingguang He1,6,
  9. Ruth Hogg2,
  10. Nathan Congdon1,2,7
  1. 1 State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
  2. 2 Centre for Public Health, Queen’s University Belfast, Belfast, UK
  3. 3 Ophthalmology Department, First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
  4. 4 Northern Ireland Methodology Hub, Centre for Public Health, Queen’s University Belfast, Belfast, UK
  5. 5 Retina and Vitreous Department, Instituto Mexicano de Oftalmologia, Queretaro, Mexico
  6. 6 Centre for Eye Research Australia, University of Melbourne, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
  7. 7 Orbis International, New York City, New York , USA
  1. Correspondence to Dr Nathan Congdon, State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong 510060, China; ncongdon1{at}gmail.com

Abstract

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° 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 60±10 years, 48% men) were examined and 1277 images were 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 weak to moderate 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.

  • telemedicine
  • epidemiology
  • retina
  • vision

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Footnotes

  • MM and TC are joint first authors.

  • Contributors NC designed the study, obtained funding for the study, initiated the collaborative project, designed data collection tools and monitored data collection for the whole study, wrote the statistical analysis plan and drafted and revised the paper. He is guarantor. MM and HM designed the study, wrote the statistical analysis plan, cleaned and analysed the data and drafted and revised the paper. TC designed the study, initiated the collaborative project, designed data collection tools and monitored data collection, wrote the statistical analysis plan and drafted and revised the paper. MAVM provided the data and revised the paper. LJ wrote the statistical analysis plan, cleaned and analysed the data and drafted and revised the paper. WX provide the data and revised the paper. MH obtained funding for the study, initiated the collaborative project and revised the paper. RH designed the study, wrote the statistical analysis plan and revised the paper. All authors had full access to data and can take responsibility for the accuracy of the data analysis.

  • Funding World Diabetes Foundation, Orbis International. Professor Congdon is supported by the Chinese government’s Thousand Man Plan and by the Ulverscroft Foundation.

  • Disclaimer The funding sources did not have any role in the design or conduct of this research.

  • Competing interests None declared.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement There are no unpublished data available from this study.

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