Use of the Stroke Recovery of Activities of Daily Living and Mobility (RAM) Index for prediction of outcome

Susan K Brenneman, University of Pennsylvania


This study examined the predictive utility of the Stroke Recovery of Activities of Daily Living and Mobility (RAM) Index. The Stroke RAM Index is a prognostic index that establishes the likelihood of a stroke survivor achieving a specific stage of recovery based on a set of clinical characteristics known at rehabilitation admission. The outcome predicted by the Stroke RAM Index is modified functional independence (Mod-FI), which specifies a minimum level of performance of activities of daily living and mobility. Database case records of 991 stroke patients discharged in 1998 were obtained from 8 acute inpatient rehabilitation facilities. The Stroke RAM Index was used to calculate the probability of achieving Mod-FI for each patient. Actual achievement or non-achievement of Mod-FI for each patient at discharge was determined. Logistic regression was performed with Mod-FI as outcome and the Stroke RAM Index variables as the set of predictors. To assess predictive utility, the area under the ROC curve, R2 statistic, and sensitivity and specificity were calculated. The results show that the Stroke RAM Index predicts as well for the 1998 sample as for the original 1990 model-building sample. The area under the ROC curve was .85 for the 1998 dataset and .86 for the 1990 dataset. Values of sensitivity, specificity for a cutpoint of probability .50 were similar to the values obtained for the 1990 dataset. Re-estimation of the model parameters resulted in different parameter estimates for some of the variables, but no improvement in predictive utility over the Stroke RAM Index. The stage of Mod-FI was achieved by 29% of the patients. Of the patients who achieved Mod-FI, 96% were discharged to the community, as opposed to 77% of those who did not achieve it. These findings suggest that the Stroke RAM Index has utility as a prognostic tool for the prediction of a specific level of function (Mod-FI). The use of the Stroke RAM Index for estimation of prognosis for stroke patients would provide a means to make equitable comparisons of outcomes across treatment settings, improve triage into the most appropriate level of care, and to confirm equating of factors in treatment effectiveness studies.

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Recommended Citation

Brenneman, Susan K, "Use of the Stroke Recovery of Activities of Daily Living and Mobility (RAM) Index for prediction of outcome" (2000). Dissertations available from ProQuest. AAI9976403.