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International variations and trends in the treatment for retinopathy of prematurity
  1. Brian A Darlow1,
  2. Kei Lui2,
  3. Satoshi Kusuda3,
  4. Brian Reichman4,
  5. Stellan Håkansson5,
  6. Dirk Bassler6,
  7. Neena Modi7,
  8. Shoo K Lee8,9,
  9. Liisa Lehtonen10,
  10. Maximo Vento11,
  11. Tetsuya Isayama8,
  12. Gunnar Sjörs12,
  13. Kjell K Helenius10,
  14. Mark Adams6,
  15. Franca Rusconi13,14,
  16. Naho Morisaki15,
  17. Prakesh S Shah8,9
  18. on behalf of the International Network for Evaluating Outcomes of Neonates
  1. 1Australia and New Zealand Neonatal Network, Department of Paediatrics, University of Otago, Christchurch, New Zealand
  2. 2Australian and New Zealand Neonatal Network, Royal Hospital for Women, National Perinatal Epidemiology and Statistic Unit, University of New South Wales, Randwick, Australia
  3. 3Neonatal Research Network Japan, Maternal and Perinatal Center, Tokyo Women's Medical University, Kawadacho, Shinjuku, Tokyo, Japan
  4. 4Israel Neonatal Network, Gertner Institute for Epidemiology and Health Policy Research, Sheba Medical Centre, Tel Hashomer, Israel
  5. 5Swedish Neonatal Quality Register, Department of Pediatrics/Neonatal Services, Umeå University Hospital, Umeå, Sweden
  6. 6Swiss Neonatal Network, Department of Neonatology, University Hospital Zurich, University of Zurich, Frauenklinikstrasse, Zurich, Switzerland
  7. 7UK Neonatal Collaborative, Neonatal Data Analysis Unit, Section of Neonatal Medicine, Department of Medicine, Imperial College London, Chelsea and Westminster Hospital campus, London, UK
  8. 8Department of Paediatrics, Mount Sinai Hospital and University of Toronto, Toronto, Ontario, Canada
  9. 9Canadian Neonatal Network, Maternal-Infant Care Research Centre, Mount Sinai Hospital, Toronto, Ontario, Canada
  10. 10Department of Pediatrics, Turku University Hospital and University of Turku, Turku, Finland
  11. 11Spanish Neonatal Network, Health Research Institute La Fe, Avenida Fernando Abril Martorell, Valencia, Spain
  12. 12Swedish Neonatal Quality Register, Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden
  13. 13TIN Toscane Online, Unit of Epidemiology, Meyer Children's University Hospital, Viale Pieraccini, Florence, Italy
  14. 14Regional Health Agency, Via Pietro Dazzi, Florence, Italy
  15. 15Neonatal Research Network Japan, Department of Social Medicine, National Center for Child Health and Development, Okura, Setagaya, Tokyo, Japan
  1. Correspondence to Professor Brian A Darlow, Department of Paediatrics, University of Otago, PO Box 4345, Christchurch 8140, New Zealand; brian.darlow{at}


Objective To compare the rates of retinopathy of prematurity (ROP) and treatment of ROP by laser or intravitreal anti-vascular endothelial growth factor among preterm neonates from high-income countries participating in the International Network for Evaluating Outcomes (iNeo) of neonates.

Methods A retrospective cohort study was conducted on extremely preterm infants weighing <1500 g at 240 to 276 weeks' gestation who were admitted to neonatal units in Australia/New Zealand, Canada, Finland, Israel, Japan, Spain, Sweden, Switzerland, Tuscany (Italy) and the UK between 2007 and 2013. Pairwise comparisons of ROP treatment in survivors between countries were evaluated by Poisson and multivariable logistic regression analyses after adjustment for confounders. A composite outcome of death or ROP treatment was compared between countries using logistic regression and standardised ratios.

Results Of 48 087 infants included in the analysis, 81.8% survived to 32 weeks postmenstrual age, and 95% of survivors were screened for ROP. Rates of any ROP ranged from 25.2% to 91.0% in Switzerland and Japan, respectively, among those examined. The overall rate of those receiving treatment was 24.9%, which varied from 4.3% to 30.4%. Adjusted risk ratios for ROP treatment were lower for Switzerland in all pairwise comparisons, whereas Japan displayed significantly higher ratios. Comparisons of the composite outcome between countries revealed similar, but less marked differences.

Conclusions Rates of any ROP and ROP treatment varied significantly between iNeo members, while an overall decline in ROP treatment was observed during the study period. It is unclear whether these variations represent differences in care practices, diagnosis and/or treatment thresholds.

  • Child health (paediatrics)
  • Epidemiology
  • Retina

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  • Correction notice This article has been corrected since it was published Online First. The definition of "FinMBR" has been corrected and affiliation number 10 has been updated.

  • Collaborators Group Information: Investigators of the International Network for Evaluating Outcomes (iNeo) of Neonates are provided in the online only supplementary material.

  • Contributors BAD conceptualised and designed the study, contributed to the interpretation of data, drafted the initial manuscript and approved the final manuscript as submitted. KL, SK, BR, SH, DB, NM, SKL, LL, MV, TI, GS, KKH, FR, NM, PSS and MA contributed to the concept, design and interpretation of data, critically reviewed and revised the draft manuscript for intellectual content and approved the final submitted version of the article. All authors agree to be accountable for all aspects of the work presented, including the accuracy and integrity of the findings reported. PSS had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

  • Funding Funding for iNeo has been provided by a Canadian Institutes of Health Research Chair in Reproductive and Child Health Services and Policy Research (APR-126340) held by PSS. The Canadian Neonatal Network is funded by financial support from the Canadian Institutes of Health Research (FRN87518) and individual participating centres. The Australian and New Zealand Neonatal Network is predominantly funded by membership contributions from participating centres. The Israel Neonatal Network very low birth weight infant database is partially funded by the Israel Center for Disease Control and the Ministry of Health. TIN Toscane online Network is funded by the Tuscany Region. The Neonatal Research Network of Japan is partly funded by a Health Labour Sciences Research Grant from the Ministry of Health, Labour and Welfare of Japan. SEN1500 is supported by funds from the Spanish Neonatal Society. The Swedish Neonatal Quality Register is funded by the Swedish Government (Ministry of Health and Social Affairs) and the body of regional healthcare providers (County Councils). SwissNeoNet is partially funded by participating units in the form of membership fees. The UK Neonatal Collaborative receives no core funding.

  • Disclaimer The funding bodies played no role in the design and conduct of the study; collection, management, analysis and interpretation of the data; preparation, review or approval of the manuscript; and decision to submit the manuscript for publication.

  • Competing interests None declared.

  • Ethics approval Mount Sinai Hospital.

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

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