P4A219: The Impact of Complex Chronic Conditions on Length of Stay and Healthcare Cost in Adults Admitted to Pediatric Hospitals

Background: The proportion of adults discharged from pediatric hospitals has increased over the past two decades. Adults admitted to children’s hospitals have longer length of stay (LOS), higher cost per encounter, and more complex chronic disease on average than children. However, it is uncertain whether the longer LOS and higher cost are due solely to the increased complexity or if age itself has an effect. Our study sought to explore and quantify the independent association of age with LOS and cost per encounter for patients admitted to children’s hospitals.

Methods: This study included all observation and inpatient encounters from January 1, 2021 – December 31, 2022 for patients over 1 year of age at 47 pediatric hospitals in the Pediatric Health Information System, except those related to pregnancy and healthy newborns. Age, gender, race/ethnicity, insurance type, organ system type and total number of complex chronic conditions (CCCs), intensive care services, LOS, and total cost were recorded for each encounter. Bivariable and multivariable regression was performed using the logarithm of LOS and total cost, with mean ratios (MR) and 95% confidence intervals (CI) reported. Stratified analysis is summarized by median LOS and cost (with interquartile ranges) for each combination of age group (1-17 years, 18-20 years, 21-25 years, and > 25 years) and number of CCCs.

Results: We included 1,215,736 patients, including 77637 (6.4%) adults 18 years or older. Although LOS increased with the number of CCCs, there was no independent association with age group when stratified (Table 1). When stratified, there remained a significant and independent association of both age group and number of CCCs with total cost per encounter (Table 1). After adjustment, there was no overall difference in LOS (p = 0.328) between age groups, with adults 18-20 years having 5% longer LOS (95% CI 5-6%), adults 21-25 years 1% longer LOS (95% CI 0-2%), and adults >25 years having 2% longer LOS (95% CI 0-4%) than children 1-17 years. There was an increasing association (p < 0.001) between age and total cost per encounter, with adults 18-20 years having 13% higher total cost (95% CI 12-15%), adults 21-25 years 25% higher total cost (95% CI 22-29%), and adults >25 years having 72% higher total cost (95% CI 66-79%) than children 1-17 years.

Conclusion: This study shows that while adult patients admitted to children’s hospitals do not have longer LOS when adjusted for other patient factors, there is an independent association between age group and total cost per encounter. This study is limited by the nature of administrative data. Further studies may investigate the contributors to specific patient population costs and whether this age-associated cost is affected by whether a patient is admitted to a children’s or adult hospital.