Premature Birth, Diagnosed

This diagnosis concept set includes diagnosis codes for children born before full term. The concept set was developed to assess other characteristics of a study cohort. It was used for exploratory analyses but it was not included as a covariate for the published analyses. It was then reused without modification for a subsequent study. The code list was generated using string searching of SNOMED concepts that mentioned terms related to prematurity. The concept set includes codes for children born before 40 weeks, but can be refined if prematurity is defined using an earlier gestational age in the study. It can also be used in combination with the pn_gestational_age variable in the PEDSnet person table, as a patient could have gestational age recorded at birth without a diagnosis code, though this variable is likely more available for patients born in hospital or admitted to the hospital as a neonate.