The Johns Hopkins Adjusted Clinical Groups® System offers multiple perspectives for characterizing and assessing variations in morbidity burden across two or more patient populations. A key strength of the ACG® System rests in its’ ability to capture the inter-relationships between co-occurring morbidities that are the hallmark of chronically ill populations that pose the greatest demands for health care resources. The clinical and statistical algorithms by which the tens of billions of potential disease combinations are distilled down to this fixed number of health status categories are the essence of the ACG System. By using the System, you can harness the power of the ambulatory and inpatient diagnostic information already captured within your organization’s databases.
Case-Mix Classification is a central feature of the ACG System, permitting comparisons between service populations that may differ significantly in terms of their overall health (morbidity burden). Comparative analyses have been used in a number of ways, including to fairly allocate health care resources, to assess provider performance, and to set insurance and reimbursement rates.
Aggregated Diagnosis Groups™(ADGs®)
ACG actuarial cells are based on building blocks called Aggregated Diagnosis Groups (ADGs). Each ADG is a grouping of diagnosis codes that are similar in terms of severity and likelihood of persistence of the health condition over time. All diagnostic codes are assigned to one of the 32 ADG clusters. Since individuals can have more than one diagnosis, they may have more than one ADG. Individual diseases or conditions are placed into a single ADG based on five clinical dimensions:
- Duration of the condition (acute, recurrent, or chronic): How long will healthcare resources be required for the management of this condition?
- Severity of the condition (e.g., minor and stable versus major and unstable): How intensely must healthcare resources be applied to manage the condition?
- Diagnostic certainty (symptoms versus documented disease): Will a diagnostic evaluation be needed or will services for treatment be the primary focus?
- Etiology of the condition (infectious, injury, or other): What types of healthcare services will likely be used?
- Specialty care involvement (e.g., medical, surgical, obstetric, hematology): To what degree will specialty care services be required?
How do ACGs Work?
Adjusted Clinical Groups are a person-focused method of categorizing patients’ illnesses. Over time, each person develops numerous conditions. Based on the pattern of these morbidities, the ACG approach assigns each individual to a single ACG category. Thus, an ACG captures the specific clustering of morbidities experienced by a person over a given period of time, such as a year. Because most management applications for population-based case-mix adjustment systems require that patients be grouped into single, mutually exclusive categories, the ACG methodology uses a branching algorithm to place people into one of 102 discrete categories based on their assigned ADGs, their age and their sex. Individuals within a given ACG experience a similar pattern of morbidity and resource consumption over the course of a given year. A patient/enrollee is assigned to a single ACG based on the diagnoses assigned by all clinicians seeing them during all contacts, regardless of setting. Thus ACGs are truly person-oriented and are not based on visits or episodes. ACGs dramatically outperform age and sex adjustment, the traditional risk-adjustment mechanism used within the health insurance industry.
