Factors influencing infant visits to emergency departments.

OBJECTIVES: To follow the 1995 birth cohort of infants, born in the State of Missouri, through their first birthday to: 1) examine their rates of visits to emergency departments (EDs), 2) identify predictors of any ED visit, 3) examine rates of nonurgent ED visits, and 4) identify predictors of nonurgent visits. METHODS: This was a retrospective population cohort study. Using deterministic linkage procedures, 2 databases at the Missouri Department of Health (DOH; (the patient abstract database and the birth registry database) were linked by DOH personnel. International Classification of Diseases, Ninth Revision-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 rates and predictors of both total and nonurgent ED visits. RESULTS: There were 935 total ED visits and 153 nonurgent ED visits per 1000 infant years. The average number of visits was.94, with 59% of infants having 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 were 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 nonurgent use. The highest rate of ED use, 1.8 per person year, was seen in white, rural infants on Medicaid, and the lowest rate (.4 per person year) was seen in urban white infants not on Medicaid. The highest rates of nonurgent use,.3 per person year, were among urban and rural Medicaid infants of both races and among black infants on commercial insurance. The lowest nonurgent rate,.04 per person year, was seen in white urban infants on commercial insurance. 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 large variations in ED usage. Increased ED use by Medicaid patients may reflect continuing difficulties in accessing primary care.

Data linkage methods used in maternally-linked birth and infant death surveillance data sets from the United States (Georgia, Missouri, Utah and Washington State), Israel, Norway, Scotland and Western Australia.

In this paper we describe the methods used to link birth and infant mortality and morbidity surveillance data sets into sibships using deterministic or multistage probabilistic linkage methods. We describe nine linked data sets: four in the United States (Georgia, Missouri, Utah and Washington State), and four elsewhere (Scotland, Norway, Israel and Western Australia). Norway and Israel use deterministic methods to link births and deaths into sibships. The deterministic linkage is usually dependent on the availability of national identification numbers. In both countries they assign these numbers at birth. Deterministic linkage is usually highly successful, and the major problem is the validation of linkages. In the United States, Western Australia and UK linkage is multistage and probabilistic. This approach is usually dependent on the calculation linkage weights from sociodemographic variables. The success rates of probabilistic methods are above 80%. Maternally-linked perinatal data open new vistas for epidemiological research. Recurrence of poor perinatal outcomes is more appropriately studied using longitudinally-linked data sets. In addition, the emergence of risk factors and the recurrence of risk factors can be studied.

Factors associated with repetition of low birthweight: Missouri longitudinal study.

The tendency to repeat low birthweight (LBW < 2500 g) was studied in 182,285 linked first and second birth Missouri livebirths for 1978-90, of which 10,701 had first birth LBW. We examined the likelihood of LBW repetition by first birth birthweight, preterm delivery, and small-for-gestational-age (SGA) status by race, and the odd ratios (ORs) of repeat LBW for risk factors such as smoking, in comparison with ORs of second birth LBW among women with normal-weight first births. We found a strong tendency to repeat LBW (21%), especially following more extreme LBW first births. Adjusted ORs for repeat LBW were 10.1 for births that were preterm and SGA; 7.9 for preterm non-SGA; and 6.3 for SGA term births. Significant ORs of LBW repetition were found for smoking (1.52 and 1.85 for smoking in second pregnancy only and both pregnancies, respectively), short interpregnancy interval (1.33), and advanced maternal age (1.17), but the ORs were generally lower than those for women with normal-weight first births. Low pre-pregnancy weight was a significant risk factor for LBW repetition.

Maternal smoking during pregnancy: no association with congenital malformations in Missouri 1980-83.

Using a multisource birth defects registry developed by the Missouri Center for Health Statistics for the years 1980-83, we examined the relation between maternal smoking during pregnancy and the occurrence of congenital malformations. There were 288,067 live singleton births in this data set of which 10,223 had one or more congenital malformations. When adjusted for potential confounders the odds ratio for congenital malformations in the infants of women who smoked during pregnancy was not increased (odds ratio = 0.98, 95% confidence interval = 0.94 - 1.03). We examined the relation between smoking and groups of malformations using the International Classification of Diseases, 9th Revision, as well as analyzing for certain specific malformations within each group and found no increased risk for infants of smokers.

Neonatal mortality in Missouri home births, 1978-84.

A study was conducted of 4,054 Missouri home births occurring from 1978 through 1984. Of the 3,645 births whose planning status was identified, 3,067 (84 per cent) were planned to be at home. Neonatal mortality was elevated for both planned (17 observed deaths vs 8.59 expected deaths) and unplanned home births (45 observed vs 33.19 expected) compared with physician-attended hospital births. Nearly all of the mortality excess for planned home births occurred in association with lesser trained attendants (12 observed vs 4.42 expected), while for unplanned home births the excess was entirely among infants weighing 1500 grams or more (19 observed vs 3.50 expected). For planned home births attended by physicians, certified nurse-midwives, or Missouri Midwife Association recognized midwives, there was little difference between observed and expected deaths (5 observed vs 3.92 expected). There also was little difference in deaths for unplanned home births weighing less than 1500 grams (26 observed vs 29.69 expected) compared with hospital births. The study provides evidence of the importance of having skilled attendants present at planned home births.