International comparison of equity gradients in hospitalizations for ambulatory care sensitive conditions

Hospitalizations for Ambulatory Care Sensitive Conditions (ACSCs) are thought to be avoidable with effective preventive care and early disease management, usually delivered in community-based ambulatory care settings. These hospitalizations are both costly and sensitive to the socioeconomic situation of patients. Understanding whether different health systems mitigate the sensitivity of ACSCs to socioeconomic gradients may direct attention to equity-improving approaches to ambulatory health care. This study sought to identify differences in the gradient of Ambulatory Care Sensitive Conditions (ACSC) relative to socioeconomic status across nine countries, namely Australia, Canada, England, Finland, France, New Zealand, Spain, Switzerland, and the United States (US). The nine countries participating in the International Collaborative on Costs, Outcomes, and Needs in Care (ICCONIC) calculated age—and sex-specific ACSC hospitalization rates between January 1, 2019, and December 31, 2019, based on data from national data sources on hospitalization and sociodemographic information at small-area levels. We used a common definition of ACSC indicators developed through a literature review of indicators routinely used in healthcare performance monitoring. We employed linear regression models to assess inequalities in ACSC association with area-level socioeconomic deprivation and income using the Slope Index of Inequality and the Relative Index of Inequality. A persistent pattern higher ACSC hospitalization rates for individuals in most disadvantaged areas remained irrespective of the socioeconomic status measure used. There was, however, considerable variation in relative equity gradients in ACSC hospitalizations between countries. Using the nine condition ACSC definition, the greatest inequalities were observed in England (RII = 0.26), and the least inequalities in ACSC hospitalizations were observed in Spain (RII = 0.68) in the 18 + cohort. A consistent equity gradient in ACSC hospitalizations was observed across high-income countries included in this study. Addressing these inequities with targeted policies can reduce the cost of care while improving access to high quality care.