Background. Admissions to hospitals for childhood asthma seem to be in
creasing, even though admissions for other childhood conditions are de
creasing. We studied admissions and readmissions for childhood asthma
in Ontario in an attempt to uncover factors relating to the admission
patterns. Methods. Using the hospital discharge data from the Canadian
Institute for Health Information, 28 646 children with diagnoses of a
sthma were identified from April 1, 1989, to March 31, 1992. Results.
The admission rates for asthma among children in Ontario showed a 14.8
% decrease from 1987 to 1992. This decline was observed primarily in 5
- to 17-year-olds. Younger children had a fourfold risk of hospital ad
mission for asthma. In the 4 years studied, 10 427 children (36.4%) we
re readmitted at least once, representing 22 114 readmissions, 16 196
(73.2%) of which were for asthma. The 6-month probabilities of readmis
sion for asthma were 20.0% (0- to 4-year-olds) and 11.7% (5- to 17-yea
r-olds). The estimated relative risks (RRs) indicated that younger chi
ldren had a significantly higher risk of readmission for asthma (RR, 1
.38; 95% confidence interval, 1.30 to 1.46) or asthma-related causes (
RR, 5.02; 95% confidence interval, 4.16 to 6.05). Conclusions. The obs
erved increasing trend in admissions for asthma among children in the
1970s and 1980s leveled off in the early 1990s. The declining admissio
n rates were largely caused by the lower admission rates among school-
aged children from 5 to 17 years. The relatively high admission and re
admission rates of preschool children are still a concern. Further res
earch is necessary to examine factors that influence admissions for as
thma among young children.