Grass pollen exposure is associated with higher readmission rates for pediatric asthma

Pediatric asthma hospital readmission is a burden on the individual and costly for Australian hospitals. Grass pollen's role, a known trigger for asthma admissions, is unexamined in readmissions. We examined the association between grass pollen and pediatric asthma readmission.

The Victorian Admitted Episodes Dataset was used to identify all primary admissions with a principal diagnosis of asthma in children aged 2-18 years between 1997 and 2009. Readmissions were defined as subsequent admissions within 28 days of index admission discharge. Generalized additive models were used to assess associations between readmission, grass pollen season, and daily grass pollen counts, lagged and cumulative. Models were further stratified by sex and age group.

Mean daily readmission was higher during grass pollen season than other times of the year, incidence rate ratio (IRR) 1.44 (95% CI, 1.03, 2.02) and for children aged 2-5 years, IRR 1.99 (1.26, 3.14). Same day grass pollen was nonlinearly associated with daily readmission for the 13-18 age group between 110 and 256 grains/m³ , p < .01. Lag 2 grass pollen was nonlinearly associated with daily readmissions overall (p = .03), boys (p = .01), and younger age groups 2-5 (p = .02) and 6-12 (p < .001).

Grass pollen exposure was associated with higher readmission rates for pediatric asthma. Treatment plans prior to discharge could be implemented to reduce the likelihood of readmission by younger children during the pollen season.