A Case-Mix System for Adults with Developmental Disabilities

Abstract

Effective management of publicly funded services matches the provision of needed services with cost-efficient payment methods. Payment systems that recognize differences in care needs (eg, case-mix systems) allow for greater proportions of available funds to be directed to providers supporting individuals with more needs. We describe a new way to allocate funds spent on adults with intellectual disabilities (ID) as part of a system-wide Medicaid payment reform initiative in Arkansas. Analyses were based on population-level data for persons living at home, collected using the interRAI ID assessment system, which were linked to paid service claims. We used automatic interactions detection to sort individuals into unique groups and provide a standardized relative measure of the cost of the services provided to each group. The final case-mix system has 33 distinct final groups and explains 26% of the variance in costs, which is similar to other systems in health and social services sectors. The results indicate that this system could be the foundation for a future case-mix approach to reimbursement and stand the test of “fairness” when examined by stakeholders, including parents, advocates, providers, and political entities.

A Case-Mix System for Children and Youth With Developmental Disabilities

“…This is a problematic practice because children and youth are significantly different to adult service users, for example, with respect to types of difficulty and relevant contextual factors. Notably, while we have previously developed a case-mix system for adults with developmental disabilities using the interRAI ID assessment tool, 16 the present study used an assessment instrument specifically for children and youth, the ChYMH-DD, to develop a case-mix model for this younger population with IDD living in private homes. The ChYRI case-mix classification system explains 30% of the variance in per diem costs for a particular set of community-based and home services.…”

“… 6 , 9 For example, our case-mix model for adults with DD explained 26% of the variance in costs. 16 Specific to the child and youth population facing special health care challenges, a study conducted by Phillips 22 used the interRAI Pediatric Home Care Assessment to develop a resource utilization system, namely, the Pediatric Home Care/Expenditure Classification Model (P/ECM). This model explained 41% of the variance in costs; however, children with IDD only accounted for a portion of the whole sample (ie, the sample population also included children and youth with medical, psychological, and developmental health conditions).…”

“…A number of different initial splits were tested and analyzed in the development of the present case-mix system, similarly to our previous work. 16 Finally, we calculated the CMIs by norming the mean cost for all observations in a particular group to a relative value (ie, by dividing by the mean cost for a selected, numerous group). The resulting classification system was dubbed “Child and Youth Resource Index” (ChYRI).…”

“…The present study describes the development efforts of a case-mix system for this younger target population, which uses the same approach we employed to develop the classification system for adults. 16 …”

The interRAI Suite of Mental Health Assessment Instruments: An Integrated System for the Continuum of Care

“…Case-mix systems have considerable value for informing a variety of health care decisions, including funding methodologies (306). These systems tend to have two main components: a) a classification system, based on clinical characteristics, to group service users into categories with similar levels of resource use; and b) a weighting system (case-mix indexes or CMIs) assigns ratiolevel numeric values to these groups that can, among other functions, be applied to funding formulas in payment systems.…”