The National Patient-Centered Clinical Research Network (PCORnet) was created to support research using clinical data collected through electronic health records. The PCORnet Antibiotic Study is one of two inaugural observational studies funded by PCORI to use the PCORnet data. The overall Aims of the project are to examine the relationship between antibiotic use before the age of 2 years and growth patterns across childhood. In this study, we characterize demographics, weight class, infections, and antibiotic use in the cohort.


Children were included in the cohort if they had at least one same-day height and weight measured in each of three age periods: 1) before 12 months, 2) 12 to 30 months, and 3) after 24 months. The initial assessment of this cohort included a distributed descriptive statistical query that ran at each institution on local versions of the PCORnet Common Data Model. The queries returned aggregate data that were combined centrally.


In 37 participating health care systems, 681,739 children met the cohort inclusion criteria. Among participants, 53% were male, 53% were white, 25% were Black, and 17% were Hispanic. Before the age of 2, 42%, 10%, and 6% received a diagnosis of suppurative otitis media, pharyngitis, and pneumonia, respectively. During this age period, 55% of children in the cohort received at least one antibiotic prescription for any indication, with 21% of children receiving one antibiotic course and 14% of children receiving 4 or more courses. One-third of children received a broad spectrum antibiotic, and 41% received a narrow spectrum antibiotic. Of 362,034 children with weight measures between ages 4 and 6 years, 28% had overweight or obesity. Of 58,341 with measures between ages 9 and 11 years, 36% had overweight or obesity.


The PCORnet Antibiotics study is a large observational study that will provide extensive data in a diverse population to examine the relationship between antibiotic use and growth patterns in children.