Length of stay and surgeries

Length of stay (LOS) was calculated as the number of days between the date of admission to hospital and the date of discharge. For hospital stays, where the date of admission and discharge occurred on the same day, the LOS was considered to be 0.5 days. Admissions associated with birth only (ie, obstetric stays immediately after birth with no additional procedures) were excluded.

Surgeries were coded according to the coding systems used in the national health systems. Italy and Spain used the ICD, Ninth Revision, Clinical Modification, England and Wales used the Office of Population Censuses and Surveys Classification of Interventions and Procedures and Finland and Denmark used national adaptions of NCSP (NOMESCO Classification of Surgical Procedures). Information on surgeries for the Northern Netherlands was incomplete and not analysed. Two paediatricians independently determined if a code was for a surgical procedure and a consensus between the two clinicians was reached over the final list of surgery codes. Online supplemental appendix table 1 summarises the broad decisions made over which procedures were considered surgeries.

archdischild-2023-326557supp001.pdf