A taxonomy of hospitals participating in Medicare accountable care organizations

Medicare was an early innovator of accountable care organizations (ACOs), establishing the Medicare Shared Savings Program (MSSP) and Pioneer programs in 2012-2013. Existing research has documented that ACOs bring together an array of health providers with hospitals serving as important participants.

Hospitals vary markedly in their service structure and organizational capabilities, and thus, one would expect hospital ACO participants to vary in these regards. Our research identifies hospital subgroups that share certain capabilities and competencies. Such research, in conjunction with existing ACO research, provides deeper understanding of the structure and operation of these organizations. Given that Medicare was an initiator of the ACO concept, our findings provide a baseline to track the evolution of ACO hospitals over time.

Hierarchical clustering methods are used in separate analyses of MSSP and Pioneer ACO hospitals. Hospitals participating in ACOs with 2012-2013 start dates are identified through multiple sources. Study data come from the Centers for Medicare and Medicaid Services, American Hospital Association, and Health Information and Management Systems Society.

Five-cluster solutions were developed separately for the MSSP and Pioneer hospital samples. Both the MSSP and Pioneer taxonomies had several clusters with high levels of health information technology capabilities. Also distinct clusters with strong physician linkages were present. We examined Pioneer ACO hospitals that subsequently left the program and found that they commonly had low levels of ambulatory care services or health information technology.

Distinct subgroups of hospitals exist in both the MSSP and Pioneer programs, suggesting that individual hospitals serve different roles within an ACO. Health information technology and physician linkages appear to be particularly important features in ACO hospitals.

ACOs need to consider not only geographic and service mix when selecting hospital participants but also their vertical integration features and management competencies.