Objectives. To follow the 1995 birth cohort of infants, born in the State o
f Missouri, through their first birthday to: 1) examine their rates of visi
ts to emergency departments (EDs), 2) identify predictors of any ED visit,
3) examine rates of nonurgent ED visits, and 4) identify predictors of nonu
Methods. This was a retrospective population cohort study. Using determinis
tic linkage procedures, 2 databases at the Missouri Department of Health (D
OH; (the patient abstract database and the birth registry database) were li
nked by DOH personnel. International Classification of Diseases, Ninth Revi
sion-Clinical Modification codes for ED visits were classified as emergent,
urgent, or nonurgent by 2 researchers. Eight newborn characteristics were
chosen for analysis. Negative binomial regression was used to examine the r
ates and predictors of both total and nonurgent ED visits.
Results. There were 935 total ED visits and 153 nonurgent ED visits per 100
0 infant years. The average number of visits was .94, with 59% of infants h
aving no visits, 21% having 1 ED visit, and 20% having 2 or more visits.
Factors associated with increases in both total and nonurgent ED visits wer
e Medicaid, self-pay, black race, rural region, presence of birth defects,
and a nursery stay of >2 days. Significant interactions were found between
Medicaid and race and Medicaid and rural regions on rates of ED use and non
The highest rate of ED use, 1.8 per person year, was seen in white, rural i
nfants on Medicaid, and the lowest rate (.4 per person year) was seen in ur
ban white infants not on Medicaid. The highest rates of nonurgent use, .3 p
er person year, were among urban and rural Medicaid infants of both races a
nd among black infants on commercial insurance. The lowest nonurgent rate,
.04 per person year, was seen in white urban infants on commercial insuranc
Conclusion. Infants in the State of Missouri have high rates of ED visits.
Nonurgent visits are only a small portion of ED visits and cannot explain l
arge variations in ED usage. Increased ED use by Medicaid patients may refl
ect continuing difficulties in accessing primary care.