MODELING CASE-MIX ADJUSTMENT OF STROKE REHABILITATION OUTCOMES

Case mix adjustment models for long-term stroke rehabilitation outcome s should be developed (1) to facilitate equitable comparisons of outco mes across treatment settings, thereby reducing disincentives for trea ting complex cases, (2) to improve triage into the most appropriate le vel of rehabilitative care after discharge from acute care, and (3) to confirm that case mix factors are equated in treatment effectiveness studies and by random assignment across conditions in clinical trials. Case mix adjustment is necessary for valid quality improvement proces ses. A conceptual model of case mix adjustment of long-term rehabilita tion outcomes is presented that (1) is diagnosis-specific, (2) include s demographic variables as important case mix factors, (3) encompasses triage into rehabilitation as well as treatment processes as aspects of quality of rehabilitative care, (4) contains outcomes measuring fun ctional status as well as mortality and morbidity, and (5) keys timing of outcomes to onset of conditions requiring rehabilitation rather th an discharge from rehabilitation. The number of potential interactions among case mix indicators requires a sophisticated analytic framework . Random factors in the model illustrate that case mix adjustment neve r be perfect. Nevertheless, it is essential. A brief review of the str oke literature on prediction of long-term outcomes suggests that addit ional work needed to specify relevant case mix indicators.