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. 2022 Sep 20;12(9):e059898. doi: 10.1136/bmjopen-2021-059898

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© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

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Selection of trend and cohort study samples, 2014. ^aDenotes exclusions that are not mutually exclusive. Individual patients/hospitalisations may be represented within multiple exclusion categories. NIS, national inpatient sample.