Materials and Methods
Statement – This systematic review of the literature was
conducted in the department of the pediatric intensive care at the Emma
Children’s Hospital in Amsterdam. The conduct and reporting of this
review adhere to the Preferred Reporting Items for Systematic Reviews
and Meta-Analyses (PRISMA)-statement23.
Search – After several scoping searches, three bibliographic
databases (PubMed, Embase.com and Clarivate Analytics/Web of Science
Core Collection) were searched for relevant literature from inception to
September 30th, 2022. Searches were devised in collaboration with a
medical information specialist (KAZ). Search terms (including synonyms),
closely related words and keywords were used as index terms or free-text
words, which were “pediatric intensive care unit” and
“inequalities”. The searches contained no date or language
restrictions that would limit results. The references of the included
full-text studies and relevant systematic reviews were searched for
additional relevant literature. Duplicate articles were excluded using
the R-package “ASYSD” an automated deduplication
tool24, followed by manual deduplication in Endnote
(X20.0.3) by the medical information specialist (KAZ). The full search
strategy used for each database is detailed in appendix A in the
supplementary material. Studies were included if they met the following
criteria: patients under the age of 18 years old (excluding premature
infants), admission to the PICU with a primary diagnosis based on a
respiratory disease, results available on outcome (defined by mortality,
PICU LOS and resource use at the PICU (e.g. support of a ventilator))
and studies reviewing health care disparities by socioeconomic factors,
insurance status, ethnicity, environmental factors or gender. Exposure
to environmental tobacco smoke (ETS) and bad nutritional status can be
seen as an indirect effect of economic recession and poverty, therefore
we decided to search for articles with smoking and diet as risk factors
as well. In addition, studies were excluded if they were of the
following publication types: editorials, letters, legal cases or
interviews.
Selection process – Two reviewers (TH and BK) independently
screened all potentially relevant titles and abstracts for eligibility
using the Rayyan software25. If necessary, the full
text article was checked for the eligibility criteria. Differences in
judgement were resolved through a consensus procedure.
Data assessment – The full text of the selected articles was
obtained for further review. Two reviewers (TH and BK) independently
evaluated the methodological quality of the full text papers using the
critical appraisal skills programme (CASP)
checklist26.