Does initial length of stay impact 30-day readmission risk in pediatric asthma patients?

Accountable care puts pressure on hospitals to manage care episodes. Initial length of stay (ILOS) and readmission risk are important elements of a care episode and measures of care quality. Understanding the association between these two measures can guide hospital efforts in managing care episodes. This study was designed to explore the association between ILOS and readmission risk in a cohort of pediatric asthma patients.

The sample cohort (n = 4965) consisted of all asthma patients discharged from Children's Hospitals and Clinics of Minnesota (CHC MN) from January 2008 through August 2012. Asthma discharges included cases with a principal diagnosis of asthma or certain respiratory cases with asthma listed as a secondary diagnosis. Multiple logistic regression was used to test associations, adjusting for covariates.

Adjusting for covariates, we found no significant association between ILOS and readmission (OR: 1.04 [95% CI: 0.98-1.10]). Analyzing ILOS categorically by length of stay, one-day stays did not have a significantly higher readmission risk (OR:1.27 [95% CI: 0.87-1.85]) than two-day stays, which had the lowest observed readmission risk. Risk increased as ILOS exceeded two days but was not significantly different by day. We found no association when comparing the difference in actual versus expected ILOS and readmission risk (shorter than expected OR: 1.13 [95% CI: 0.74-1.71]; longer than expected OR: 0.97 [95% CI: 0.69-1.38]).

Attempts to prolong ILOS would dramatically increase costs with little impact on readmissions. For example, increasing one-day visits to two-day visits would increase hospital patient days 38% (1870 d) in this cohort while decreasing total readmissions by 3.8% [95% CI: 3.6-4.0%]. Understanding the mechanisms that impact readmissions is essential in evaluating cost-effective approaches to improving patient outcomes and lowering the cost of care.