ACKNOWLEDGMENTS

HTI
Author affiliations: Population Policy and Practice Department, UCL Great Ormond Street Institute of Child Health, University College London, London, United Kingdom (Daniel Tompsett, Ania Zylbersztejn, Pia Hardelid, Bianca De Stavola).A Medical Research Council (MRC) Methodology Grant (number MR/R025215/1) supported D.T. and B.D., and a Wellcome Trust Seed Award in Science (number 207673/Z/17/Z) supported A.Z. and P.H.The Hospital Treatment Insights database (HTI) is maintained by IQVIA (We would like to thank Hassy Dattani and Tanith Hjelmbjerg for their help with accessing the Hospital Treatment Insights database. This work uses data provided by patients and collected by the National Health Service as part of their care and support.Conflict of interest: none declared.