Measuring Medical Complexity During Inpatient Rehabilitation After Traumatic Brain Injury

Abstract

Ryser DK, Egger MJ, Horn SD, Handrahan D, Gandhi P, Bigler ED. Measuring medical complexity during inpatient rehabilitation after traumatic brain injury. Arch Phys Med Rehabil 2005;86:1108–17. Objective To compare the performance of 3 severity of illness (SOI) indices—the Comprehensive Severity Index (CSI), All Patient Refined Diagnosis Related Groups Severity of Illness, case-mix group (CMG)—and 5 well-known neurologic parameters, as measures of medical complexity. Design Retrospective chart review. Setting Inpatient rehabilitation center within a level I trauma center. Participants Consecutive traumatic brain injury (TBI) admissions (N=212). Intervention Acute inpatient TBI rehabilitation. CSI and neurologic parameters were scored by chart extraction. SOI was based on diagnosis codes by using 3M PC Grouper software, version 15. Main Outcome Measures Adjusted R 2 was used to predict rehabilitation charges as a proxy of medical complexity. Results The highest adjusted R 2 values for single variables predicting charges were: CMG .349, CSI .293, duration of posttraumatic amnesia .260. Adjusted R 2 values for the CMG combined with the CSI, 5 neurologic parameters, and SOI to predict charges were .446, .431, and .365, respectively. Conclusions The CMG was the best single predictor of rehabilitation charges for TBI. Predictive ability was better when the CMG was combined with the CSI or a combination of the 5 neurologic parameters. A severity index based on objective clinical findings rather than diagnostic codes may have distinct advantages for rehabilitation outcome studies and reimbursement methodology.