Determining preventable acute care spending among high-cost patients in a single-payer public health care system

Background Research has shown that a small proportion of patients account for the majority of health care spending. The objective of this analysis was to determine the amount and proportion of preventable acute care spending among high-cost patients. Methods We examined a population-based sample of all adult high-cost patients using linked administrative health care data housed at ICES in Toronto, Ontario. High-cost patients were defined as those in and above the 90th percentile of the cost distribution. Preventable acute care (emergency department visits and hospitalisations) was defined using validated algorithms. We estimated costs of preventable and non-preventable acute care for high- and non-high-cost patients by category of visit/ condition. We replicated our analysis for persistent high-cost patients and high-cost patients under 65 years and those 65 years and older. Results We found that 10% of all acute care spending among high-cost patients was considered preventable; this figure was higher for non-high-cost patients (25%). The proportion of preventable acute care spending was higher for persistent highcost patients (14%) and those 65 years and older (12%). Among ED visits, the largest portion of preventable care spending was for primary care treatable conditions; for hospitalisations, the highest proportions of preventable care spending were for COPD, bacterial pneumonia and urinary tract infections. Conclusions Although high-cost patients account for a substantial proportion of health care costs, there seems to be limited scope to prevent acute care spending among this patient population. Nonetheless, care coordination and improved access to primary care, and disease prevention may prevent some acute care.