Parkerson G R, Michener J L, Yarnall K S, Hammond W E
Department of Community and Family Medicine, Duke University Medical Center, Durham, NC 27710, USA.
J Clin Epidemiol. 1997 Dec;50(12):1385-94. doi: 10.1016/s0895-4356(97)00217-5.
The Duke Case-Mix System (DUMIX), which combines age, gender, patient-reported perceived and physical health status, and provider-reported or auditor-reported severity of illness to classify patients by their risk of high future utilization, explained 17.1% of the variance in future clinic charges and 16.6% of the variance in return visits. When a random half of 413 ambulatory adults were classified into four risk classes by predictive regression coefficients from the other half, there was a stepwise increase in actual future utilization by risk class. The most accurate classification was for Class 4 (highest risk) patients, with a sensitivity of 40.8%, specificity of 82.1%, and likelihood ratio of 2.3. These 23.7% of patients accounted for 44.2% of charges for all patients. When predictive coefficients from this population were used to classify a different group of 206 ambulatory adults, past utilization also increased in stepwise order by case-mix class.
