PCORnet Antibiotics and Childhood Growth Study: Process for Cohort Creation and Cohort Description

Abstract

Objectives: The National Patient-Centered Clinical Research Network (PCORnet) supports observational and clinical research using health care data. The PCORnet Antibiotics and Childhood Growth Study is one of PCORnet's inaugural observational studies. We sought to describe the processes used to integrate and analyze data from children across 35 participating institutions, the cohort characteristics, and prevalence of antibiotic use.

Methods: We included children in the cohort if they had at least one same-day height and weight measured in each of 3 age periods: 1) before 12 months, 2) 12 to 30 months, and 3) after 24 months. We distributed statistical queries that each institution ran on its local version of the PCORnet Common Data Model, with aggregate data returned for analysis. We defined overweight or obesity as age- and sex-specific body mass index ≥85th percentile, obesity ≥95th percentile, and severe obesity ≥120% of the 95th percentile.

Results: A total of 681,739 children met the cohort inclusion criteria, and participants were racially/ethnically diverse (24.9% black, 17.5% Hispanic). Before 24 months of age, 55.2% of children received at least one antibiotic prescription; 21.3% received a single antibiotic prescription; 14.3% received 4 or more; and 33.3% received a broad-spectrum antibiotic. Overweight and obesity prevalence was 27.6% at age 4 to <6 years (n = 362,044) and 36.2% at 9 to <11 years (n = 58,344).

Conclusions: The PCORnet Antibiotics and Childhood Growth Study is a large national longitudinal observational study in a diverse population that will examine the relationship between early antibiotic use and subsequent growth patterns in children.

Keywords: antibiotics; body mass index; childhood growth; childhood obesity; electronic health records; research infrastructure.

Figure 1.

PCORnet Antibiotics Study, Prescribing Rate and Breakdown of Antibiotic Spectrum by Network Partner This figure presents the percent of children who receive an antibiotic prescription before 24 months of age overall for the cohort and by Network Partner for those contributing at least 5,000 children to the cohort (A) and the percent of children receiving any narrow and broad spectrum antibiotic before 24 months of age overall and by Network Partner (B). The denominator for A includes all children in the cohort; for B, it includes all children who received at least one antibiotic prescription before 24 months of age. Among the 23 Network Partners presented, 16 had antibiotic prescribing rates of greater than 50% and had higher narrow spectrum antibiotic prescribing rates than broad.

Figure 2.

PCORnet Antibiotics Study, Cohort Weight Class The study calculated age- and sex-specific BMI (BMI z-score) for children at each age period. World Health Organization (WHO) growth standards for children were utilized before 24 months of age: underweight if BMI z-score was <2.3^rd percentile, normal weight if 2.3^rd to <97.7^th percentile, and overweight/obesity if ≥97.7^th percentile (A). The Centers for Disease Control and Prevention (CDC) NHANES 2000 growth charts for children were utilized for children from 2 to 10.9 years: underweight if BMI z-score <5^th percentile, normal weight 5^th to <85^th, overweight 85^th to <95^th percentile, obesity ≥95^th percentile, and severe obesity ≥120% of the 95^th percentile (B). Rates of overweight, obesity, and severe obesity were higher for old children.