Ambulatory Care-Sensitive Hospital Admissions: Health System Prevention Quality Indicator or Population Health? - Abstract
Background: Admission rates for ambulatory care-sensitive conditions (ACSCs) are often used by health systems as a measure of access to effective primary and preventive care. However, there is debate about whether ACSC admissions primarily reflect other social determinants of population health and are largely insensitive to ambulatory care quality. Methods: This study analyzes adult ACSC admissions of Cook County, Illinois residents to 173 Illinois hospitals from 2016-2018. Agency for Healthcare Research and Quality Prevention Quality Indicators (PQIs) were calculated to compute ACSC hospitalization rates per 1000 residents across four census data-defined zip code poverty level areas (>20%, 10-19.99%, 5-9.99% and <5% poor households). ACSC hospitalization rates were compared to rates for all other (non-ACSC) medical and surgical conditions. Results: There were 1,384,880 medical and surgical admissions of Cook County residents age 20 and older from 2016 -2018, including 13.3% classified as ACSC admissions. Residents of the highest poverty level zip code area had ACSC rates 70% higher than the most affluent zip code area. In the poorest versus most affluent areas, non-ACSC medical admissions had a 102% higher rate and admission rate among severely ill patients (Charlson Score>3) was doubled. By comparison, non-ACSC surgical admission rates had only a 6% difference across poverty level zip code areas. Conclusions: These findings indicate that ACSC admission rates mirror non-ACSC medical, but not surgical, causes of admissions. Using the ACSC admission rate to measure access to primary care may obscure how general prevalence of chronic illness drives hospital use among low-income populations.