High health care costs among adults with intellectual and developmental disabilities: a population-based study.

OBJECTIVE: While it is generally accepted that adults with intellectual and developmental disabilities (IDDs) use health services to a greater extent than the general population, there is remarkably little research that focuses on the costs associated with their health care. Using population-based data from adults with IDD in Ontario, this study aimed to estimate overall health care costs, classify individuals into high and non-high cost categories and describe differences in the demographics, clinical profiles and health care use patterns between these groups.

DESIGN: A retrospective cohort study based in Ontario, Canada, was conducted with the use of linked administrative health data.

METHODS: A costing algorithm developed for the general population in Ontario was applied to estimate health care costs of adults with IDD under age 65 for 2009 and 2010. Individuals were categorised into two groups according to whether their total annual health care costs were among the highest decile in the general population. These groups were compared on demographic and clinical variables, and relative mean costs for six types of health care services in the two groups were computed. In addition, we computed the proportion of individuals who remained in the high cost group over 2 years.

RESULTS: Among adults with IDD, 36% had annual health care expenditures greater than $2610 CAD (top decile of all Ontario adults under 65). These individuals were more likely to be female, to be in the oldest age groups, to live in group homes and to be receiving disability income support than individuals whose expenditures were below the high cost threshold. In addition, they had higher rates of all the physical and mental health conditions studied. Greatest health care expenses were due to hospitalisations, especially psychiatric hospitalisations, continuing care/rehabilitation costs and medication costs. The majority of individuals whose health care costs placed them in the high cost category in 2009 remained in that category a year later.

DISCUSSION: Adults with IDD are nearly 4 times as likely to incur high annual health care costs than those without IDD. Individuals with IDD and high health care costs have unique health and demographic profiles compared with adults with IDD whose annual health care costs are below the high cost threshold. Attending to their health care needs earlier in their health care trajectory may be an opportunity to improve health and reduce overall health care costs. It is important that we explore how to best meet their needs. Models proposed to meet the needs of adults with high health care costs in the general population may not apply to this unique group.