Table 4

Assessment of study quality (categorising babies by gestational age) using modified QUIPS tool (for in-depth analysis, see online supplementary tables S1 and S2)

Type of study (comparator groups)StudyCriteria of modified QUIPS tool
Study participation (population, exclusion criteria, comparison of baseline characteristics between comparator groups)Study attrition (prospective or retrospective, data source, completeness of data on demographic/confounding factors, proportion of babies outcome analysis carried out on)Prognostic factor measurement (definition of birth location, explanation of facilities available at different level units)Outcome measurement (definition)Study confounding (adjustment for confounding factors, which variables used)
Inutero versus exutero transfer to NICULamont et al28xxxx
Truffert et al31xxxx
Hauspy et al32xxxx
Lee et al33xx
Boland et al13xx
Level of unit of birth (NICU vs non-NICU)Holmgren and Högberg34xx
Johansson et al29x
Level of unit of care (NICU vs non-NICU)Field et al30xxxxx
Jonas and Lumley35xx
  • denotes adequate quality, and x indicates inadequate quality.

  • NICU, neonatal intensive care unit; QUIPS, QUality In Prognostic Studies.