DUKE CASE-MIX SYSTEM (DUMIX) FOR AMBULATORY HEALTH-CARE

The Duke Case Mix System (DUMIX), which combines age, gender, patient- reported perceived and physical health status, and provider-reported o r auditor-reported severity of illness to classify patients by their r isk of high future utilization, explained 17.1% of the variance in fut ure clinic charges and 16.6% of the variance in return visits. When a random half of 413 ambulatory adults were classified into four risk cl asses by predictive regression coefficients from the other half, there was a stepwise increase in actual future utilization by risk class. T he most accurate classification was for Class 4 (highest risk) patient s, with a sensitivity of 40.8%, specificity of 82.1%, and likelihood r atio of 2.3. These 23.7% of patients accounted for 44.2% of charges fo r all patients. When predictive coefficients from this population were used to classify a different group of 206 ambulatory adults, past uti lization also increased in stepwise order by case-mix class. (C) 1997 Elsevier Science Inc.